<![CDATA[Scivillage.com Casual Discussion Science Forum - Astrophysics, Cosmology & Astronomy]]>

<![CDATA[Scivillage.com Casual Discussion Science Forum - Astrophysics, Cosmology & Astronomy]]> https://www.scivillage.com/ Sun, 27 Sep 2026 17:15:25 +0000 MyBB <![CDATA[Cosmic lockdown: how the environment can isolate quantum fields]]> https://www.scivillage.com/thread-21427.html Fri, 25 Sep 2026 16:39:28 +0000 C C]]> https://www.scivillage.com/thread-21427.html https://jnews.sissamedialab.it/en/cosmic...tum-fields

PRESS RELEASE: The vacuum is not always so empty. "When we talk about a vacuum in cosmology, we do not mean completely devoid of energy," explains David Wands, Professor at the Institute of Cosmology & Gravitation at the University of Portsmouth. "A vacuum is rather a state in which a field sits at a minimum of its energy. The true vacuum is the lowest possible minimum, but there can also be local minima, which we call false vacua."

We can picture this as a landscape made up of valleys of different depths: the true vacuum is the deepest one, while the others are false vacua. Something sitting in one of these depressions can remain "trapped" there even if, somewhere else, a lower-energy state exists.

This is exactly what can happen to quantum fields, fundamental physical objects that permeate the Universe. A classical field is something that has a value at every position in space, like a magnetic field, whose strength changes from point to point. Quantum fields behave in a similar way, and their excitations appear as particles.

In a new study published in JCAP, Robson Christie, Jaewoo Joo, Greg Kaplanek, Vincent Vennin and David Wands used a simplified model to investigate what determines which vacuum a field may end up in within an expanding Universe.

The case of the Higgs field. To understand why this question matters, the authors themselves point to the case of the Higgs field. Its vacuum value contributes to giving mass to the particles of the Standard Model — the theory that describes the known elementary particles and three of the four fundamental forces — and helps determine the structure of low-energy physics.

According to some calculations based on the Standard Model, it is possible that the Higgs field does not sit in the lowest possible energy state, but in a false vacuum, while at very large field values a second, deeper minimum may exist.

The study is not directly about the Higgs field, but uses it as a concrete example of what can happen when a field becomes trapped in a local minimum even though a lower-energy state is available.

“In principle, a transition to that deeper minimum would take the Universe into a radically different state, in which the structure of matter and the forces that govern it would be altered,” explains Robson Christie, a researcher at the School of Mathematics and Physics at the University of Portsmouth and first author of the study.

Such a transition can be made possible by a quantum phenomenon. Let us return to the picture of vacua as valleys separated by mountains. In classical physics, a system sitting at the bottom of the shallower valley can reach the deeper one only if it has enough energy to climb over the mountain between them. In quantum mechanics, by contrast, the state of the system can extend beyond the barrier, leaving a small probability that it will appear on the other side: this is quantum tunnelling.

No field is ever truly isolated. In their work, Christie and colleagues built a simplified model to understand how the environment affects the evolution of a field. Many calculations of tunnelling treat the field as completely isolated.

“We know, however, that perfect isolation is an idealisation,” explains Greg Kaplanek, a researcher at Syracuse University, New York. In reality, fields continuously interact with other fields and with what surrounds them — in other words, with their environment. “Think, for example, of quantum computers: we go to enormous lengths to protect the quantum information stored in these machines from the environment, because even weak interactions with it can quickly alter the quantum state. Something similar happens in cosmology: a field is never really alone.”

Interactions with the environment produce a phenomenon known as decoherence. A quantum system can exist in a superposition of different possibilities: using the analogy of a coin, it is not simply heads or tails, but a quantum state that includes both possibilities at once. Interaction with the environment makes it increasingly difficult to keep this superposition, causing the system to behave more and more like an ordinary classical system.

In the authors’ model, the environment is represented by other fields interacting with the main field. The latter can also initially be in a quantum superposition involving both vacua. One of the surprises of the study, however, is that the environment does not appear to play a decisive role in the initial choice of vacuum.

Light fields and heavy fields. What matters more is whether the field is “light” or “heavy” relative to the Hubble scale, that is, relative to the rate at which the Universe is expanding.

“A field that is heavy compared with the Hubble scale can quickly adjust to the changes as the Universe expands,” Christie explains, “and in this case it is highly likely to move towards the true vacuum, the deepest energy minimum.”

Something different happens for lighter fields. “If the expansion is too rapid compared with the dynamics of the field, the system cannot keep up with the changes,” Christie continues. “In this case there can remain a significant probability that the field will also end up in the false vacuum.”

In other words, the initial choice between the true and false vacuum is influenced mainly by the relationship between the field’s own dynamics and the rate of cosmic expansion.

Cosmic lockdown. So let us imagine a light field that has ended up in a false vacuum. What happens next?

In a perfectly isolated quantum system, tunnelling towards the other minimum would still be possible. But in the authors’ model, interaction with the environment produces decoherence and destroys the quantum properties needed to maintain a coherent superposition between the two vacua.

“The interesting thing is that it is not primarily the environment that decides where the field will end up,” explains Kaplanek. “Once the field has localised in one of the two minima, however, decoherence tends to keep it there. Tunnelling towards the other vacuum is strongly suppressed.”

This is the phenomenon the authors call “cosmic lockdown”: a kind of lock that stabilises the field in the vacuum it has reached. The authors interpret it as a manifestation of the quantum Zeno effect: under certain conditions, a quantum system that is continuously monitored can have much more difficulty moving from one state to another.

Of course, no one is literally observing the field in the model. “You do not need a conscious observer,” Kaplanek explains. “The environment continuously gathers information about the state of the system. This process destroys the coherence between the two possible vacua and makes tunnelling from one to the other much more difficult.”

Good news for our Universe? The work remains a simplified model and does not show that our current Higgs vacuum is protected by cosmic lockdown. The result does, however, suggest an interesting principle: interactions with the environment can make a false vacuum more stable by suppressing tunnelling towards another state.

“If a mechanism of this kind were relevant in more realistic cosmological situations, then it could help stabilise a field that is already sitting in a false vacuum,” Wands concludes. “But understanding how far this can be applied to the Higgs field will require more realistic models.”

If our Higgs field really is sitting in a false vacuum, then cosmic lockdown points to at least one reassuring possibility: interaction with its surroundings could help make a transition to a radically different state even more difficult.]]> https://jnews.sissamedialab.it/en/cosmic...tum-fields

PRESS RELEASE: The vacuum is not always so empty. "When we talk about a vacuum in cosmology, we do not mean completely devoid of energy," explains David Wands, Professor at the Institute of Cosmology & Gravitation at the University of Portsmouth. "A vacuum is rather a state in which a field sits at a minimum of its energy. The true vacuum is the lowest possible minimum, but there can also be local minima, which we call false vacua."

We can picture this as a landscape made up of valleys of different depths: the true vacuum is the deepest one, while the others are false vacua. Something sitting in one of these depressions can remain "trapped" there even if, somewhere else, a lower-energy state exists.

This is exactly what can happen to quantum fields, fundamental physical objects that permeate the Universe. A classical field is something that has a value at every position in space, like a magnetic field, whose strength changes from point to point. Quantum fields behave in a similar way, and their excitations appear as particles.

In a new study published in JCAP, Robson Christie, Jaewoo Joo, Greg Kaplanek, Vincent Vennin and David Wands used a simplified model to investigate what determines which vacuum a field may end up in within an expanding Universe.

The case of the Higgs field. To understand why this question matters, the authors themselves point to the case of the Higgs field. Its vacuum value contributes to giving mass to the particles of the Standard Model — the theory that describes the known elementary particles and three of the four fundamental forces — and helps determine the structure of low-energy physics.

According to some calculations based on the Standard Model, it is possible that the Higgs field does not sit in the lowest possible energy state, but in a false vacuum, while at very large field values a second, deeper minimum may exist.

The study is not directly about the Higgs field, but uses it as a concrete example of what can happen when a field becomes trapped in a local minimum even though a lower-energy state is available.

“In principle, a transition to that deeper minimum would take the Universe into a radically different state, in which the structure of matter and the forces that govern it would be altered,” explains Robson Christie, a researcher at the School of Mathematics and Physics at the University of Portsmouth and first author of the study.

Such a transition can be made possible by a quantum phenomenon. Let us return to the picture of vacua as valleys separated by mountains. In classical physics, a system sitting at the bottom of the shallower valley can reach the deeper one only if it has enough energy to climb over the mountain between them. In quantum mechanics, by contrast, the state of the system can extend beyond the barrier, leaving a small probability that it will appear on the other side: this is quantum tunnelling.

No field is ever truly isolated. In their work, Christie and colleagues built a simplified model to understand how the environment affects the evolution of a field. Many calculations of tunnelling treat the field as completely isolated.

“We know, however, that perfect isolation is an idealisation,” explains Greg Kaplanek, a researcher at Syracuse University, New York. In reality, fields continuously interact with other fields and with what surrounds them — in other words, with their environment. “Think, for example, of quantum computers: we go to enormous lengths to protect the quantum information stored in these machines from the environment, because even weak interactions with it can quickly alter the quantum state. Something similar happens in cosmology: a field is never really alone.”

Interactions with the environment produce a phenomenon known as decoherence. A quantum system can exist in a superposition of different possibilities: using the analogy of a coin, it is not simply heads or tails, but a quantum state that includes both possibilities at once. Interaction with the environment makes it increasingly difficult to keep this superposition, causing the system to behave more and more like an ordinary classical system.

In the authors’ model, the environment is represented by other fields interacting with the main field. The latter can also initially be in a quantum superposition involving both vacua. One of the surprises of the study, however, is that the environment does not appear to play a decisive role in the initial choice of vacuum.

Light fields and heavy fields. What matters more is whether the field is “light” or “heavy” relative to the Hubble scale, that is, relative to the rate at which the Universe is expanding.

“A field that is heavy compared with the Hubble scale can quickly adjust to the changes as the Universe expands,” Christie explains, “and in this case it is highly likely to move towards the true vacuum, the deepest energy minimum.”

Something different happens for lighter fields. “If the expansion is too rapid compared with the dynamics of the field, the system cannot keep up with the changes,” Christie continues. “In this case there can remain a significant probability that the field will also end up in the false vacuum.”

In other words, the initial choice between the true and false vacuum is influenced mainly by the relationship between the field’s own dynamics and the rate of cosmic expansion.

Cosmic lockdown. So let us imagine a light field that has ended up in a false vacuum. What happens next?

In a perfectly isolated quantum system, tunnelling towards the other minimum would still be possible. But in the authors’ model, interaction with the environment produces decoherence and destroys the quantum properties needed to maintain a coherent superposition between the two vacua.

“The interesting thing is that it is not primarily the environment that decides where the field will end up,” explains Kaplanek. “Once the field has localised in one of the two minima, however, decoherence tends to keep it there. Tunnelling towards the other vacuum is strongly suppressed.”

This is the phenomenon the authors call “cosmic lockdown”: a kind of lock that stabilises the field in the vacuum it has reached. The authors interpret it as a manifestation of the quantum Zeno effect: under certain conditions, a quantum system that is continuously monitored can have much more difficulty moving from one state to another.

Of course, no one is literally observing the field in the model. “You do not need a conscious observer,” Kaplanek explains. “The environment continuously gathers information about the state of the system. This process destroys the coherence between the two possible vacua and makes tunnelling from one to the other much more difficult.”

Good news for our Universe? The work remains a simplified model and does not show that our current Higgs vacuum is protected by cosmic lockdown. The result does, however, suggest an interesting principle: interactions with the environment can make a false vacuum more stable by suppressing tunnelling towards another state.

“If a mechanism of this kind were relevant in more realistic cosmological situations, then it could help stabilise a field that is already sitting in a false vacuum,” Wands concludes. “But understanding how far this can be applied to the Higgs field will require more realistic models.”

If our Higgs field really is sitting in a false vacuum, then cosmic lockdown points to at least one reassuring possibility: interaction with its surroundings could help make a transition to a radically different state even more difficult.]]> <![CDATA[The Axis Of Evil]]> https://www.scivillage.com/thread-21411.html Wed, 23 Sep 2026 18:49:07 +0000 Magical Realist]]> https://www.scivillage.com/thread-21411.html <![CDATA[68% of physicists don’t think that time started at the big bang (cosmology)]]> https://www.scivillage.com/thread-21362.html Thu, 17 Sep 2026 18:06:11 +0000 C C]]> https://www.scivillage.com/thread-21362.html https://www.popsci.com/science/physicist...ng-survey/

EXCERPT: After reviewing answers from over 1,600 physicists, the questionnaire’s authors published their key takeaways earlier this year in Physics Magazine. The results? Physicists are very divided on explanations for some of the universe’s fundamental operations.

The most dramatic relates to the big-bang theory (technically known as the Lambda Cold Dark Matter theory). About 68 percent of respondents said they don’t think the famous moment necessarily marks the beginning of time. Some of this has to do with how the big bang is presented in popular culture—contrary to many depictions, the theory specifically explains how the universe expanded from a single extremely hot, dense prior state of existence. This means it technically may have very little to do with the beginning of time.

The only other majority opinion pertains to the immediate moments following the big bang. Only 51 percent of physicists agreed that the immediate moments following the big bang involved an incomprehensibly fast period of expansion commonly known as inflation.

Subjects got far more contentious from there, although some of it was understandable. Given how much remains to still learn about dark matter, 17 percent of survey takers think the mysterious material is composed of an undiscovered particle or particles. Around 12 percent argued it could be explained by tweaking the theory of gravity. At best, barely 21 percent of physicists hypothesized it may be some combination of these and other answers.

Quantum physics continues the chaos. Nearly 19 percent of scientists think string theory is likely the best way to integrate gravity into quantum physics, while only 12 percent offered loop quantum gravity as an alternative. Meanwhile, 18 percent lean towards the suspicion that gravity can’t be integrated in any way.

If the survey presents one clear takeaway, it’s that these diverse theories are in no way an indictment of the present-day state of physics. These aren’t amateurs—they’re researchers who base their arguments on volumes’ worth of data, calculations, and scientific testing... (MORE - missing details)]]> https://www.popsci.com/science/physicist...ng-survey/

EXCERPT: After reviewing answers from over 1,600 physicists, the questionnaire’s authors published their key takeaways earlier this year in Physics Magazine. The results? Physicists are very divided on explanations for some of the universe’s fundamental operations.

The most dramatic relates to the big-bang theory (technically known as the Lambda Cold Dark Matter theory). About 68 percent of respondents said they don’t think the famous moment necessarily marks the beginning of time. Some of this has to do with how the big bang is presented in popular culture—contrary to many depictions, the theory specifically explains how the universe expanded from a single extremely hot, dense prior state of existence. This means it technically may have very little to do with the beginning of time.

The only other majority opinion pertains to the immediate moments following the big bang. Only 51 percent of physicists agreed that the immediate moments following the big bang involved an incomprehensibly fast period of expansion commonly known as inflation.

Subjects got far more contentious from there, although some of it was understandable. Given how much remains to still learn about dark matter, 17 percent of survey takers think the mysterious material is composed of an undiscovered particle or particles. Around 12 percent argued it could be explained by tweaking the theory of gravity. At best, barely 21 percent of physicists hypothesized it may be some combination of these and other answers.

Quantum physics continues the chaos. Nearly 19 percent of scientists think string theory is likely the best way to integrate gravity into quantum physics, while only 12 percent offered loop quantum gravity as an alternative. Meanwhile, 18 percent lean towards the suspicion that gravity can’t be integrated in any way.

If the survey presents one clear takeaway, it’s that these diverse theories are in no way an indictment of the present-day state of physics. These aren’t amateurs—they’re researchers who base their arguments on volumes’ worth of data, calculations, and scientific testing... (MORE - missing details)]]> <![CDATA[Sun may have swallowed a super-Earth planet & could still be hiding the evidence?]]> https://www.scivillage.com/thread-21323.html Sun, 13 Sep 2026 17:02:20 +0000 C C]]> https://www.scivillage.com/thread-21323.html https://www.space.com/astronomy/sun/the-...e-evidence

EXCERPTS: Yildiz and colleagues theorize that the sun's act of planetary infanticide may help to explain differences between observations of the sun and what is predicted by models of stellar evolution. This includes the depth of the sun's convection zone and the so-called sound-speed structure just below the convection zone. It could also explain why the surface of the sun is depleted of the element lithium.

"By modelling the sun's evolution and comparing the results with precise observations of its interior, we find that the ingestion of a super-Earth could help explain long-standing differences between standard solar models and observations, including subtle changes in the sun's internal structure and its depleted lithium abundance," Yildiz said. "We were interested in whether these problems might have a common origin in the early chemical history of the sun."

The researcher explained that young stars like the sun during its infancy are surrounded by vast flattened clouds of gas and dust called protoplanetary discs, where substantial amounts of material can move between the disc and the star.

"Since planets are made of material that is chemically different from the gas in the disc, we wondered whether the early engulfment of a planet could have left a chemical signature inside the young sun," Yildiz said.

[...] Their results found the best fit for the sun's current characteristics was the cannibalism of a planet between five and ten times the mass of the Earth, a type of planet called a super-Earth. This could explain the strange, unpredicted characteristics of the sun.

[....] "The earlier work proposed that a super-Earth could have formed and migrated into the young sun. Our paper asks whether the sun itself could still carry observable evidence that such an engulfment actually happened, and we believe it could," Yildiz concluded. "The next step is to see if these fingerprints can be independently detected... (MORE - missing details)]]> https://www.space.com/astronomy/sun/the-...e-evidence

EXCERPTS: Yildiz and colleagues theorize that the sun's act of planetary infanticide may help to explain differences between observations of the sun and what is predicted by models of stellar evolution. This includes the depth of the sun's convection zone and the so-called sound-speed structure just below the convection zone. It could also explain why the surface of the sun is depleted of the element lithium.

"By modelling the sun's evolution and comparing the results with precise observations of its interior, we find that the ingestion of a super-Earth could help explain long-standing differences between standard solar models and observations, including subtle changes in the sun's internal structure and its depleted lithium abundance," Yildiz said. "We were interested in whether these problems might have a common origin in the early chemical history of the sun."

The researcher explained that young stars like the sun during its infancy are surrounded by vast flattened clouds of gas and dust called protoplanetary discs, where substantial amounts of material can move between the disc and the star.

"Since planets are made of material that is chemically different from the gas in the disc, we wondered whether the early engulfment of a planet could have left a chemical signature inside the young sun," Yildiz said.

[...] Their results found the best fit for the sun's current characteristics was the cannibalism of a planet between five and ten times the mass of the Earth, a type of planet called a super-Earth. This could explain the strange, unpredicted characteristics of the sun.

[....] "The earlier work proposed that a super-Earth could have formed and migrated into the young sun. Our paper asks whether the sun itself could still carry observable evidence that such an engulfment actually happened, and we believe it could," Yildiz concluded. "The next step is to see if these fingerprints can be independently detected... (MORE - missing details)]]> <![CDATA[Did Venus eat its own moon?]]> https://www.scivillage.com/thread-21304.html Thu, 10 Sep 2026 21:42:08 +0000 C C]]> https://www.scivillage.com/thread-21304.html https://www.space.com/astronomy/venus/di...s-own-moon

EXCERPTS: One question that scientists have puzzled over for years is whether Venus always lacked a moon, or if the hottest planet in the solar system once had a natural satellite and somehow lost it. Now, a team of researchers may have arrived at an answer, determining the fate that would have befallen a hypothetical moon orbiting Venus.

"I have always had a fascination with moon formation and evolution in the solar system, and particularly with Venus since my research is centered around its evolution and potential for past habitability," team leader Stephen R. Kane of the University of California, Riverside told Space.com. "Venus is Earth's twin, and both are nearly identical in size, mass, and composition. However, Earth has a large moon, and Venus has no moon at all, not even a small captured satellite.

"Venus undoubtedly experienced large impacts, just as Earth has, and so has had as much, if not more, opportunity to form a moon similar to what we see in our own skies."

Kane and colleagues constructed a simulation to test their ideas of what could have become of the Venusian moon.

"The work involved going back to fundamental physics and creating the simulation from the ground up, which I validated by ensuring I could reproduce the evolution of the Earth-moon system," Kane said. "The moment I realized that our model provided a complete explanation for Venus not having a moon was an exciting one!"

[...] But are there any circumstances under which a Venusian moon could have survived?

"Survival came down to two main things: Venus had to be spinning fast when the moon formed, with a day shorter than about 12 hours, and the moon couldn't be too massive, up to roughly the mass of our own moon," team leader Stephen R. Kane of the University of California, Riverside told Space.com. "In that narrow window, the moon migrates outward and stabilizes, much as Earth's did. Outside that range, the moon is unfortunately doomed to be consumed by Venus.

"So a surviving moon would have had to be modest in size, orbiting a rapidly spinning early Venus, which are conditions that don't match what we think early Venus was actually like."

We may never conclusively know if Venus has indeed destroyed its own moon, as Kane thinks that collecting direct evidence from astronomical observations will be very difficult. (MORE - missing details)]]> https://www.space.com/astronomy/venus/di...s-own-moon

EXCERPTS: One question that scientists have puzzled over for years is whether Venus always lacked a moon, or if the hottest planet in the solar system once had a natural satellite and somehow lost it. Now, a team of researchers may have arrived at an answer, determining the fate that would have befallen a hypothetical moon orbiting Venus.

"I have always had a fascination with moon formation and evolution in the solar system, and particularly with Venus since my research is centered around its evolution and potential for past habitability," team leader Stephen R. Kane of the University of California, Riverside told Space.com. "Venus is Earth's twin, and both are nearly identical in size, mass, and composition. However, Earth has a large moon, and Venus has no moon at all, not even a small captured satellite.

"Venus undoubtedly experienced large impacts, just as Earth has, and so has had as much, if not more, opportunity to form a moon similar to what we see in our own skies."

Kane and colleagues constructed a simulation to test their ideas of what could have become of the Venusian moon.

"The work involved going back to fundamental physics and creating the simulation from the ground up, which I validated by ensuring I could reproduce the evolution of the Earth-moon system," Kane said. "The moment I realized that our model provided a complete explanation for Venus not having a moon was an exciting one!"

[...] But are there any circumstances under which a Venusian moon could have survived?

"Survival came down to two main things: Venus had to be spinning fast when the moon formed, with a day shorter than about 12 hours, and the moon couldn't be too massive, up to roughly the mass of our own moon," team leader Stephen R. Kane of the University of California, Riverside told Space.com. "In that narrow window, the moon migrates outward and stabilizes, much as Earth's did. Outside that range, the moon is unfortunately doomed to be consumed by Venus.

"So a surviving moon would have had to be modest in size, orbiting a rapidly spinning early Venus, which are conditions that don't match what we think early Venus was actually like."

We may never conclusively know if Venus has indeed destroyed its own moon, as Kane thinks that collecting direct evidence from astronomical observations will be very difficult. (MORE - missing details)]]> <![CDATA[The universe is fine-tuned for technology, not just life (cosmological philosophy)]]> https://www.scivillage.com/thread-21282.html Tue, 08 Sep 2026 15:23:28 +0000 C C]]> https://www.scivillage.com/thread-21282.html The universe is fine-tuned for technology, not just life
https://iai.tv/articles/the-universe-is-..._auid=2020

INTRO: The universe seems to be fine-tuned for life. Were nature’s constants even slightly different, life wouldn’t exist. To explain this, scientists reach for bizarre ideas, like an infinite multiverse. But physicist and technologist Jeff Shainline thinks we’ve been missing a crucial clue. The universe isn’t just fine-tuned for life, but also for the creation of technology - humanity itself is just one step in this longer evolutionary process. He uses this observation to build a new case for an overlooked explanation of fine-tuning: Lee Smolin’s proposal that universes reproduce through black holes and, like organisms, evolve across cosmic generations towards fecundity. Life and technology, Shainline argues, are not the point of the universe, but parts of its reproductive strategy. (MORE - details)]]> The universe is fine-tuned for technology, not just life
https://iai.tv/articles/the-universe-is-..._auid=2020

INTRO: The universe seems to be fine-tuned for life. Were nature’s constants even slightly different, life wouldn’t exist. To explain this, scientists reach for bizarre ideas, like an infinite multiverse. But physicist and technologist Jeff Shainline thinks we’ve been missing a crucial clue. The universe isn’t just fine-tuned for life, but also for the creation of technology - humanity itself is just one step in this longer evolutionary process. He uses this observation to build a new case for an overlooked explanation of fine-tuning: Lee Smolin’s proposal that universes reproduce through black holes and, like organisms, evolve across cosmic generations towards fecundity. Life and technology, Shainline argues, are not the point of the universe, but parts of its reproductive strategy. (MORE - details)]]> <![CDATA[Saturn's decagon + Mars could hold the secrets to the origin of life]]> https://www.scivillage.com/thread-21261.html Fri, 04 Sep 2026 16:55:02 +0000 C C]]> https://www.scivillage.com/thread-21261.html Mars could hold the secrets to the origin of life
https://iai.tv/articles/mars-could-hold-..._auid=2020

INTRO: After a Nature paper provided possible indications of past life on Mars, neuroscientist and philosopher Erik Hoel makes the case that Mars could act as a planetary museum for life’s origins. For example, Mars has no plate tectonics to bury the possible signs of life captured by NASA, no foundations laid over it, no footsteps trampling it… and so the so-called “leopard spots” suggesting mineral leftovers of long-dead microbes are effectively untouched and frozen in time. Hoel argues we must go to Mars to investigate; not only as a scientific pursuit, but as an existential one. (MORE - detaisl)

Mysterious decagon unexpectedly appeared around Saturn’s south pole.
https://www.smithsonianmag.com/smart-new...180989449/

EXCERPTS: In a study published in Science Advances, researchers describe the discovery of a decagon—a ten-sided polygon—wrapped around Saturn’s south pole. It appears to be a huge, evolving atmospheric wave within one of the planet’s jet streams. Scientists don’t know what caused its sudden appearance, and they’re not sure how long it might stick around.

“The discovery of the wave really did come as a surprise, as neither earlier images of Saturn taken by the Hubble Space Telescope nor those captured by the Cassini spacecraft whilst orbiting the planet between 2004 and 2017 had shown it,” Agustín Sánchez-Lavega, lead author of the study and a planetary scientist at the University of the Basque Country in Spain, tells Science Alert’s Michelle Starr.

[...] While the decagon seems to be a relatively new structure, Saturn’s experience with polygons goes back much further. More than 40 years ago, the two Voyager spacecraft discovered another regular-sided feature on the planet: a hexagonal jet stream around its north pole that’s still around today. The study demonstrates that “the ‘unique’ hexagon is not as extraordinary as we thought,” Sánchez-Lavega tells the Associated Press’ Marcia Dunn.

Still, there are several differences between the two shapes. ... As is often the case with scientific mysteries, the answer lies in collecting additional data and conducting further analysis. (MORE - missing details)

https://youtu.be/8P5gI9JERDs

https://www.youtube-nocookie.com/embed/8P5gI9JERDs]]> Mars could hold the secrets to the origin of life
https://iai.tv/articles/mars-could-hold-..._auid=2020

INTRO: After a Nature paper provided possible indications of past life on Mars, neuroscientist and philosopher Erik Hoel makes the case that Mars could act as a planetary museum for life’s origins. For example, Mars has no plate tectonics to bury the possible signs of life captured by NASA, no foundations laid over it, no footsteps trampling it… and so the so-called “leopard spots” suggesting mineral leftovers of long-dead microbes are effectively untouched and frozen in time. Hoel argues we must go to Mars to investigate; not only as a scientific pursuit, but as an existential one. (MORE - detaisl)

https://www.youtube-nocookie.com/embed/8P5gI9JERDs]]> <![CDATA[Comets may have transported water to a young planetary system]]> https://www.scivillage.com/thread-21243.html Wed, 02 Sep 2026 16:50:30 +0000 C C]]> https://www.scivillage.com/thread-21243.html https://www.nature.com/articles/s41467-026-76880-y

PRESS RELEASE: Astronomers at Lund University in Sweden have found evidence of exocomets – comets in other solar systems – orbiting a young star similar to our Sun. The observations point to a possible mechanism for how water might be transported from the cold outer regions of the planetary system to regions where planets form.

The PDS 70 planetary system is just over five million years old and lies around 370 light-years from Earth. The system has at least two gas giants and orbits a star that is slightly cooler than the Sun. Water vapour was detected near the star as early as 2023. Researchers in Lund have now shown that variations in sodium gas in front of the star may be a sign of comets passing through the inner parts of the system.

“Our study suggests that comets may be responsible for transporting water to the inner parts of the planetary system, where planets can form, in the same way as in the early Solar System,” says Aline Novais, an astronomy researcher at Lund University.

The researchers have analysed observations from 2018 and detected sodium gas moving at several kilometres per second relative to the star. The gas appears and disappears over the course of several nights – a pattern consistent with what one would expect when comets pass in front of a star. When a comet approaches its star, it heats up and the ice on its surface turns directly into gas – a process known as sublimation. The gas can then leave a measurable imprint in the star’s light.

“This is the first time we have seen evidence of exocomets orbiting a star that is relatively cool, much like our Sun. Furthermore, this system is the youngest in which exocomet activity has been proposed,” says Aline Novais.

The researchers have also simulated the comets’ orbits. The results show that objects far out in the planetary system can be affected by the gravitational pull of the gas giants and flung towards the star. This is particularly interesting because comets form in the cold outer regions of the planetary system, where water may exist as ice. If they are then channelled inwards, they can transport water and other volatile substances to the region where planets form.

“It is reminiscent of a possible process in the early Solar System, in which comets may have helped to deliver water to the young Earth,” says Alexandra Stockwell Murphy, an astronomer at Lund University.

Where the Earth’s water originally came from remains an open question. Water-rich asteroids and comets are two possible sources. PDS 70 gives researchers the opportunity to study a similar process whilst a planetary system is still in its early stages of development.

“And when the Extremely Large Telescope, which is currently being built in Chile, becomes operational in the coming years, we will be able to find out whether there are any further planets in the system and thus gain an even clearer picture of how water and other building blocks of planets are transported,” concludes Jens Hoeijmakers, an astronomy researcher at Lund University.

PAPER: http://dx.doi.org/10.1038/s41467-026-76880-y]]> https://www.nature.com/articles/s41467-026-76880-y

PRESS RELEASE: Astronomers at Lund University in Sweden have found evidence of exocomets – comets in other solar systems – orbiting a young star similar to our Sun. The observations point to a possible mechanism for how water might be transported from the cold outer regions of the planetary system to regions where planets form.

The PDS 70 planetary system is just over five million years old and lies around 370 light-years from Earth. The system has at least two gas giants and orbits a star that is slightly cooler than the Sun. Water vapour was detected near the star as early as 2023. Researchers in Lund have now shown that variations in sodium gas in front of the star may be a sign of comets passing through the inner parts of the system.

“Our study suggests that comets may be responsible for transporting water to the inner parts of the planetary system, where planets can form, in the same way as in the early Solar System,” says Aline Novais, an astronomy researcher at Lund University.

The researchers have analysed observations from 2018 and detected sodium gas moving at several kilometres per second relative to the star. The gas appears and disappears over the course of several nights – a pattern consistent with what one would expect when comets pass in front of a star. When a comet approaches its star, it heats up and the ice on its surface turns directly into gas – a process known as sublimation. The gas can then leave a measurable imprint in the star’s light.

“This is the first time we have seen evidence of exocomets orbiting a star that is relatively cool, much like our Sun. Furthermore, this system is the youngest in which exocomet activity has been proposed,” says Aline Novais.

The researchers have also simulated the comets’ orbits. The results show that objects far out in the planetary system can be affected by the gravitational pull of the gas giants and flung towards the star. This is particularly interesting because comets form in the cold outer regions of the planetary system, where water may exist as ice. If they are then channelled inwards, they can transport water and other volatile substances to the region where planets form.

“It is reminiscent of a possible process in the early Solar System, in which comets may have helped to deliver water to the young Earth,” says Alexandra Stockwell Murphy, an astronomer at Lund University.

Where the Earth’s water originally came from remains an open question. Water-rich asteroids and comets are two possible sources. PDS 70 gives researchers the opportunity to study a similar process whilst a planetary system is still in its early stages of development.

“And when the Extremely Large Telescope, which is currently being built in Chile, becomes operational in the coming years, we will be able to find out whether there are any further planets in the system and thus gain an even clearer picture of how water and other building blocks of planets are transported,” concludes Jens Hoeijmakers, an astronomy researcher at Lund University.

PAPER: http://dx.doi.org/10.1038/s41467-026-76880-y]]> <![CDATA[Can someone possibly see the edge of spacetime?]]> https://www.scivillage.com/thread-21223.html Mon, 31 Aug 2026 15:14:11 +0000 C C]]> https://www.scivillage.com/thread-21223.html https://bigthink.com/starts-with-a-bang/...spacetime/

KEY POINTS: In all directions, in all locations, there seems only to be more Universe from our perspective, with the only edge to spacetime set by the limits of how far back in time we can see: all the way back to the Big Bang. But what we understand our Universe to be may not be all there is; our Big Bang could just be one location in space and time where cosmic inflation ended, giving rise to a bubble universe within a sea of inflating space. While we see no evidence for such an edge to the part of the Universe we can observe, it’s possible that someone born right up against such a bubble wall would indeed see an edge. Here’s what that would look like.

EXCERPT: Now, it’s true: we’re not close to one of those edges, and such an edge isn’t contained within our observable Universe. But we can imagine — if this picture is indeed correct — what someone would see if they did come into existence close to one of those edges.

The answer, as frustrating as it would be, is just that: an abrupt edge. We would see isotropy and homogeneity everywhere we looked, until we encountered that edge. And then, wherever that edge occurs in space, there would be absolutely nothing.

No stars. No galaxies. No normal matter. No dark matter. No neutrinos. Not even the leftover glow of the Big Bang, since all of the primordial radiation that originated in that direction would have already passed you by.

All that would be there, beyond the “edge” of the region where the hot Big Bang occurred, would be nothing. You’d simply observe an abrupt end that cuts across one hemisphere of the sky, ellipsoidally shaped from your perspective, with an angular size that corresponded to how close you were to that edge and how much time and expansion had elapsed since the hot Big Bang occurred in your region of space... (MORE - missing details)]]> https://bigthink.com/starts-with-a-bang/...spacetime/

KEY POINTS: In all directions, in all locations, there seems only to be more Universe from our perspective, with the only edge to spacetime set by the limits of how far back in time we can see: all the way back to the Big Bang. But what we understand our Universe to be may not be all there is; our Big Bang could just be one location in space and time where cosmic inflation ended, giving rise to a bubble universe within a sea of inflating space. While we see no evidence for such an edge to the part of the Universe we can observe, it’s possible that someone born right up against such a bubble wall would indeed see an edge. Here’s what that would look like.

EXCERPT: Now, it’s true: we’re not close to one of those edges, and such an edge isn’t contained within our observable Universe. But we can imagine — if this picture is indeed correct — what someone would see if they did come into existence close to one of those edges.

The answer, as frustrating as it would be, is just that: an abrupt edge. We would see isotropy and homogeneity everywhere we looked, until we encountered that edge. And then, wherever that edge occurs in space, there would be absolutely nothing.

No stars. No galaxies. No normal matter. No dark matter. No neutrinos. Not even the leftover glow of the Big Bang, since all of the primordial radiation that originated in that direction would have already passed you by.

All that would be there, beyond the “edge” of the region where the hot Big Bang occurred, would be nothing. You’d simply observe an abrupt end that cuts across one hemisphere of the sky, ellipsoidally shaped from your perspective, with an angular size that corresponded to how close you were to that edge and how much time and expansion had elapsed since the hot Big Bang occurred in your region of space... (MORE - missing details)]]> <![CDATA[Physicists reconstruct the collision that launched a runaway black hole]]> https://www.scivillage.com/thread-21165.html Mon, 24 Aug 2026 17:41:17 +0000 C C]]> https://www.scivillage.com/thread-21165.html https://www.eurekalert.org/news-releases/1141188

EXCERPTS: In September 2022, astronomers noticed a perplexing feature on an image of a galaxy around 7.5 billion light-years from Earth. A thin line stretching over 202,000 light-years pointed directly away from the galaxy’s center. Its leading edge was an unresolved point, with no detectable stars, speeding away at nearly 1,000 kilometers per second.

The scientists who spotted it interpreted the feature as a super-massive black hole plowing through intergalactic space, triggering star formation in its wake. Now researchers from UC Santa Barbara and University of Texas at Austin have published a paper on the violent event that could have shot this behemoth from its host galaxy.

The findings, published in Physical Review Letters, provide the first account of a class of black hole mergers predicted by general relativity, and will help scientists prepare for the next generation of gravitational wave observatories.

Merging black holes produce strong gravitational waves as the massive objects warp spacetime and spiral into each other. If the system is lopsided, these waves can generate enough of a kick to launch the newly formed, larger black hole in an entirely different trajectory, “like the recoil of a fired cannon,” said co-author Tejaswi Venumadhav, an associate professor in UCSB’s Department of Physics.

[...] “The two black holes had to be spinning fast,” explained lead author Tousif Islam, a postdoctoral scholar at UCSB’s Kavli Institute for Theoretical Physics (KITP). “And their spins had to be misaligned.”

[...] Enormous black holes appear to have developed relatively early in the history of the cosmos. But by the time the parents of RBH-1 met more than 7.5 billion years ago, neighboring super-massive black holes would’ve consolidated, leaving a single behemoth at the center of each galaxy. So this pair wouldn’t have encountered each other unless their home galaxies themselves collided... (MORE - missing details, no ads)]]> https://www.eurekalert.org/news-releases/1141188

EXCERPTS: In September 2022, astronomers noticed a perplexing feature on an image of a galaxy around 7.5 billion light-years from Earth. A thin line stretching over 202,000 light-years pointed directly away from the galaxy’s center. Its leading edge was an unresolved point, with no detectable stars, speeding away at nearly 1,000 kilometers per second.

The scientists who spotted it interpreted the feature as a super-massive black hole plowing through intergalactic space, triggering star formation in its wake. Now researchers from UC Santa Barbara and University of Texas at Austin have published a paper on the violent event that could have shot this behemoth from its host galaxy.

The findings, published in Physical Review Letters, provide the first account of a class of black hole mergers predicted by general relativity, and will help scientists prepare for the next generation of gravitational wave observatories.

Merging black holes produce strong gravitational waves as the massive objects warp spacetime and spiral into each other. If the system is lopsided, these waves can generate enough of a kick to launch the newly formed, larger black hole in an entirely different trajectory, “like the recoil of a fired cannon,” said co-author Tejaswi Venumadhav, an associate professor in UCSB’s Department of Physics.

[...] “The two black holes had to be spinning fast,” explained lead author Tousif Islam, a postdoctoral scholar at UCSB’s Kavli Institute for Theoretical Physics (KITP). “And their spins had to be misaligned.”

[...] Enormous black holes appear to have developed relatively early in the history of the cosmos. But by the time the parents of RBH-1 met more than 7.5 billion years ago, neighboring super-massive black holes would’ve consolidated, leaving a single behemoth at the center of each galaxy. So this pair wouldn’t have encountered each other unless their home galaxies themselves collided... (MORE - missing details, no ads)]]> <![CDATA[Does uneven cosmic expansion change our fate?]]> https://www.scivillage.com/thread-21154.html Sat, 22 Aug 2026 17:18:37 +0000 C C]]> https://www.scivillage.com/thread-21154.html https://bigthink.com/starts-with-a-bang/...sion-fate/

KRY POINTS: If you can measure both how fast the Universe is expanding today and how the cosmic expansion rate has changed over time, you can learn what makes up your Universe, and that determines your ultimate fate. Our standard model of cosmology is dominated by dark energy, with matter and radiation of all types being sub-dominant only by the present day, indicating that dark energy dominates our fate: portending a likely heat death. But recently, a series of measurements have pointed to a Universe that isn’t expanding isotropically: the same in all directions. Could that alter our fate? And if so, what are the implications?

EXCERPT: The expanding Universe, the Big Bang, and dark energy’s existence and properties are so thoroughly well-established that these final options seem unlikely; it would take extraordinary evidence to overturn current thought. But that’s why we keep investigating even the flimsiest of clues. After all, the greatest strength of science is that we continuously attempt to disprove and discredit even our most cherished scientific ideas. Only the ones that can survive each and every challenge will persist; the rest are relegated to the dustbin of historical also-rans... (MORE - details)]]> https://bigthink.com/starts-with-a-bang/...sion-fate/

KRY POINTS: If you can measure both how fast the Universe is expanding today and how the cosmic expansion rate has changed over time, you can learn what makes up your Universe, and that determines your ultimate fate. Our standard model of cosmology is dominated by dark energy, with matter and radiation of all types being sub-dominant only by the present day, indicating that dark energy dominates our fate: portending a likely heat death. But recently, a series of measurements have pointed to a Universe that isn’t expanding isotropically: the same in all directions. Could that alter our fate? And if so, what are the implications?

EXCERPT: The expanding Universe, the Big Bang, and dark energy’s existence and properties are so thoroughly well-established that these final options seem unlikely; it would take extraordinary evidence to overturn current thought. But that’s why we keep investigating even the flimsiest of clues. After all, the greatest strength of science is that we continuously attempt to disprove and discredit even our most cherished scientific ideas. Only the ones that can survive each and every challenge will persist; the rest are relegated to the dustbin of historical also-rans... (MORE - details)]]> <![CDATA[Signal that could upend cosmology + What if the whole cosmos developed by evolution?]]> https://www.scivillage.com/thread-21133.html Wed, 19 Aug 2026 17:16:23 +0000 C C]]> https://www.scivillage.com/thread-21133.html Cosmic birefringence: the signal that could upend cosmolog
https://bigthink.com/starts-with-a-bang/...cosmology/

KRY POINTS: We assume there's no preferred frame of reference in the Universe, and that light behaves the same in all directions. What if we're wrong? The foundational principle of cosmology is the Copernican principle: the idea that we occupy no special place in the Universe, either in space, time, or orientation. A few observations can test this: looking for preferred directionality to galaxy rotations, for asymmetries in densities in the sky, for abnormalities in cosmic history, or from the Big Bang’s leftover light, the CMB. If light’s polarization gets inherently rotated, even by a fraction of a degree, it would mean there is a preferred direction to the Universe, and could indicate an exotic ingredient, or even a fundamental flaw, in our cosmic picture. (MORE - details)

What if the entire cosmos developed by evolution, too?
https://www.smithsonianmag.com/science-n...180989338/

EXCERPTS: Historically, scientists have viewed the cosmos as akin to a rock-complex, perhaps even beautiful, but formed through arbitrary events. Evolutionary cosmologists instead argue that universes, like living organisms, grow and reproduce, spinning off new universes with small variations from their progenitors. In doing so, these cosmic offspring are refined across generations into forms that maximize the number of universes yet to be born. Since the Big Bang, our universe, like any developing child, has been unfurling into an optimal shape.

Under this view, the universe is not a rock. It is an egg. [...] Julian Gough assumed someone else must have come up with the idea of an evolving cosmos before he did. A search through the scientific literature confirmed that someone had: Lee Smolin, a founding member of the Perimeter Institute for Theoretical Physics.

Smolin’s work was, in turn, inspired by physicists Bryce DeWitt and John Wheeler, who proposed that singularities inside black holes, the places where matter is crushed into a point of infinite density, might expand to produce new universes that follow different physics from the universes that produced them. Every universe-including our own-would, under this logic, have emerged from a Big Bang within a black hole.

Smolin realized that this hypothetical process would allow universes to reproduce, in a way, by making more black holes. And if those new universes could inherit the physics of their parents with small differences-just as new organisms inherit the genes of their parents with small differences-then universes could also evolve with each generation. Specifically, a form of cosmic natural selection would favor universes that make as many black holes as possible. Less fertile universes could persist, but they would produce far fewer offspring. So over time, an increasingly high proportion of universes would be optimized for black hole production-which would imply that our universe, given the odds, is one of those.

Smolin published his ideas in a 1992 paper titled “Did the Universe Evolve?” as well as a 1997 popular-science book called The Life of the Cosmos. Gough found both and read them excitedly. And yet, it seemed as though virtually nothing had come of Smolin’s ideas since.

[...] cosmic evolution did not make predictions that were easily testable at the time of its origin. But when Gough rediscovered the idea in the mid-2010s, that had changed: The upcoming launch of the James Webb Space Telescope was about to reshape the study of the universe’s first billion years.

[...] On July 8, 2022, four days before Webb released its first data, Gough published his predictions on Substack. Already aware that his amateur background might make him sound unreliable, he feared being publicly wrong. “I was really terrified,” he says. “This could be fantastically humiliating.”

Fortunately for Gough, the results were the opposite. Webb found galaxies forming earlier, faster and in a more orderly manner than standard physics models had anticipated. In November 2022, NASA reported evidence that some galaxies had begun assembling only about 100 million years after the Big Bang, while follow-up observations of a galaxy just 470 million years after the event found an unusually massive black hole-nearly as massive as all the stars surrounding it.

[...] ince making those predictions, Gough has received funding from grant programs [...] Cosmological evolution would need to explain how black holes, which appear to crush everything inside them into an infinitely dense point, could produce universes inside of them that expand outward, like ours. Some recent research does indicate that our own universe might reside in a black hole.

[...] For now, the theory’s strongest appeal may be the reach of the idea behind it. Evolution “is always the best explanation,” Gough says, when asked about Dennett’s framing of evolution as a universal acid. “He’s correct. … Why wouldn’t it apply to universes when it applies to everything else?” (MORE - missing details)]]> <![CDATA[Spherical "Aerobots" may one day swarm the caves of Titan]]> https://www.scivillage.com/thread-21113.html Mon, 17 Aug 2026 16:20:40 +0000 C C]]> https://www.scivillage.com/thread-21113.html Spherical "Aerobots" may one day swarm the caves of Titan — a moon of Saturn that NASA says is one of the most Earthlike in our solar system.
https://www.space.com/technology/nasa-fu...moon-titan

INTRO: Titan is covered in rivers, lakes and seas of hydrocarbons, like methane and ethane, as well as a strange "karst" terrain including underground sinkholes and caves. No rover could easily traverse this surface, but flying vehicles may have more success.

So a new grant, under the early-stage NASA Innovative Advanced Concepts (NIAC) program, aims to create small, flying vehicles that could explore those caves. It's unclear if the aerobots — called SPARK, or Solid-state Propulsion for Autonomous Reconnaissance of Karst — would be ready in time for NASA's Dragonfly mission to Titan, project lead Daniel Drew, an assistant professor at the University of Hawaii at Mānoa, told Space.com.

That's because SPARK is beginning a nine-month Phase 1 grant and would need to at least get through the up-to-two-year Phase 2 before things look "more realistic" for a liftoff, he noted. Dragonfly, meanwhile, is targeted for a 2028 launch but if the mission is delayed, that provides more possibilities for late-mission additions.

"Where does that line up with the current Titan mission timeline, assuming we've missed the window for Dragonfly? I don't know," Drew said of SPARK. But whenever the mission lifts off, Drew said SPARK has a good chance of doing well on Titan with its novel ion (electric) thrusters. (MORE - details)]]> Spherical "Aerobots" may one day swarm the caves of Titan — a moon of Saturn that NASA says is one of the most Earthlike in our solar system.
https://www.space.com/technology/nasa-fu...moon-titan

INTRO: Titan is covered in rivers, lakes and seas of hydrocarbons, like methane and ethane, as well as a strange "karst" terrain including underground sinkholes and caves. No rover could easily traverse this surface, but flying vehicles may have more success.

So a new grant, under the early-stage NASA Innovative Advanced Concepts (NIAC) program, aims to create small, flying vehicles that could explore those caves. It's unclear if the aerobots — called SPARK, or Solid-state Propulsion for Autonomous Reconnaissance of Karst — would be ready in time for NASA's Dragonfly mission to Titan, project lead Daniel Drew, an assistant professor at the University of Hawaii at Mānoa, told Space.com.

That's because SPARK is beginning a nine-month Phase 1 grant and would need to at least get through the up-to-two-year Phase 2 before things look "more realistic" for a liftoff, he noted. Dragonfly, meanwhile, is targeted for a 2028 launch but if the mission is delayed, that provides more possibilities for late-mission additions.

"Where does that line up with the current Titan mission timeline, assuming we've missed the window for Dragonfly? I don't know," Drew said of SPARK. But whenever the mission lifts off, Drew said SPARK has a good chance of doing well on Titan with its novel ion (electric) thrusters. (MORE - details)]]> <![CDATA[Why gravity can’t be an instantaneous force in the cosmos]]> https://www.scivillage.com/thread-21091.html Fri, 14 Aug 2026 16:37:56 +0000 C C]]> https://www.scivillage.com/thread-21091.html https://bigthink.com/starts-with-a-bang/...instantly/

KEY POINTS: When Newton first formulated his theory of gravity, he imagined masses attracting one another, instantaneously, from any great distance across the Universe. But it turns out that no signals, not even gravity, can travel faster than the speed of light: the cosmic speed limit for any and all particles and/or forces. It took an Einsteinian revolution to restore cosmic order to gravity, and recent observations have confirmed that the speed of gravity really is equal to the speed of light. Here’s how we know... (MORE - details)]]> https://bigthink.com/starts-with-a-bang/...instantly/

KEY POINTS: When Newton first formulated his theory of gravity, he imagined masses attracting one another, instantaneously, from any great distance across the Universe. But it turns out that no signals, not even gravity, can travel faster than the speed of light: the cosmic speed limit for any and all particles and/or forces. It took an Einsteinian revolution to restore cosmic order to gravity, and recent observations have confirmed that the speed of gravity really is equal to the speed of light. Here’s how we know... (MORE - details)]]> <![CDATA[European Eclipse]]> https://www.scivillage.com/thread-21085.html Thu, 13 Aug 2026 02:57:16 +0000 Yazata]]> https://www.scivillage.com/thread-21085.html

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