Sep 23, 2021 02:40 AM
(This post was last modified: Sep 23, 2021 02:42 AM by C C.)
Scientists are searching for clusters of spacetime-eating bubbles in the cosmos
https://www.vice.com/en/article/m7ey7b/s...the-cosmos
INTRO: Cosmology deals with some of the trippiest ideas in science, but the notion of vacuum bubbles that can potentially create and destroy universes is pretty mind-boggling even for this field. Yet, these hypothetical bubbles of nothing in spacetime are a major topic of research and scientists are honing in on possible avenues to observationally confirm their existence.
The bizarre bubbles are manifestations of a concept in quantum field theory known as false vacuum decay. Consider a vacuum that is in a stable state, but that still contains slightly more energy than a “true” vacuum that occupies the minimum energy state in the universe. This “false” vacuum could be somehow kicked into the true vacuum state of minimum energy, and this transition—or decay—would cause a bubble of true vacuum to form (or nucleate) and expand out into space, consuming everything around it.
Some models suggest that our universe was born as a true vacuum bubble that exists within a multiverse containing many similar bubbles, while others posit that we currently inhabit a false vacuum that might one day be destroyed by the advance of a true vacuum bubble.
Now, scientists led by Dalila Pîrvu, a doctoral student at the Perimeter Institute for Theoretical Physics, have shed light on the formation and interactions of these hypothetical bubbles by running a new type of decay simulation that includes variables that other models omit.
The results reveal that bubbles might form in clusters, as opposed to popping up at random positions in spacetime, a finding that could help scientists figure out how to look for real observational signatures to confirm the existence of these bubbles. The team’s research is also “the first time biasing has been investigated in the context of bubble formation in vacuum decay,” according to the study, which was recently posted on the preprint server arXiv... (MORE)
Astronomers have discovered a giant, empty cavity lurking in space
https://www.sciencealert.com/astronomers...y-in-space
INTRO: It may not appear so to us, but the space between the stars isn't completely empty. Tenuous and not-so-tenuous clouds of gas and dust drift in the darkness.
A region of space some 700 light-years away is a fascinating exception. There, among the constellations of Perseus and Taurus, astronomers have found a large, spherical void over 500 light-years in diameter. Around its perimeter are the Perseus and Taurus molecular clouds – dense clouds of cold gas and dust where stars form.
It's called the Per-Tau Shell, and it seems to be the product of at least one giant supernova explosion millions of years ago. It's likely that this phenomenon compressed and triggered star formation in the two molecular clouds.
"Hundreds of stars are forming or exist already at the surface of this giant bubble," said theoretical astrophysicist Shmuel Bialy of the Harvard-Smithsonian Center for Astrophysics (CfA). "We have two theories – either one supernova went off at the core of this bubble and pushed gas outward forming what we now call the 'Perseus-Taurus Supershell', or a series of supernovae occurring over millions of years created it over time."
Mapping things in space is a tricky prospect. In two dimensions, it's pretty straightforward, but the third dimension – depth – takes a little more work. We have a number of ways of doing so, but there are gaps in our knowledge, and many uncertainties remain.
To explore the Perseus and Taurus molecular clouds, the researchers used data from Gaia, the European Space Agency's satellite observatory, which has been working since 2013 to map the Milky Way galaxy in three dimensions with the most detail and highest precision achievable. It's one of the most powerful tools we have for helping us understand the architecture – and therefore the history – of our home galaxy... (MORE)
https://www.vice.com/en/article/m7ey7b/s...the-cosmos
INTRO: Cosmology deals with some of the trippiest ideas in science, but the notion of vacuum bubbles that can potentially create and destroy universes is pretty mind-boggling even for this field. Yet, these hypothetical bubbles of nothing in spacetime are a major topic of research and scientists are honing in on possible avenues to observationally confirm their existence.
The bizarre bubbles are manifestations of a concept in quantum field theory known as false vacuum decay. Consider a vacuum that is in a stable state, but that still contains slightly more energy than a “true” vacuum that occupies the minimum energy state in the universe. This “false” vacuum could be somehow kicked into the true vacuum state of minimum energy, and this transition—or decay—would cause a bubble of true vacuum to form (or nucleate) and expand out into space, consuming everything around it.
Some models suggest that our universe was born as a true vacuum bubble that exists within a multiverse containing many similar bubbles, while others posit that we currently inhabit a false vacuum that might one day be destroyed by the advance of a true vacuum bubble.
Now, scientists led by Dalila Pîrvu, a doctoral student at the Perimeter Institute for Theoretical Physics, have shed light on the formation and interactions of these hypothetical bubbles by running a new type of decay simulation that includes variables that other models omit.
The results reveal that bubbles might form in clusters, as opposed to popping up at random positions in spacetime, a finding that could help scientists figure out how to look for real observational signatures to confirm the existence of these bubbles. The team’s research is also “the first time biasing has been investigated in the context of bubble formation in vacuum decay,” according to the study, which was recently posted on the preprint server arXiv... (MORE)
Astronomers have discovered a giant, empty cavity lurking in space
https://www.sciencealert.com/astronomers...y-in-space
INTRO: It may not appear so to us, but the space between the stars isn't completely empty. Tenuous and not-so-tenuous clouds of gas and dust drift in the darkness.
A region of space some 700 light-years away is a fascinating exception. There, among the constellations of Perseus and Taurus, astronomers have found a large, spherical void over 500 light-years in diameter. Around its perimeter are the Perseus and Taurus molecular clouds – dense clouds of cold gas and dust where stars form.
It's called the Per-Tau Shell, and it seems to be the product of at least one giant supernova explosion millions of years ago. It's likely that this phenomenon compressed and triggered star formation in the two molecular clouds.
"Hundreds of stars are forming or exist already at the surface of this giant bubble," said theoretical astrophysicist Shmuel Bialy of the Harvard-Smithsonian Center for Astrophysics (CfA). "We have two theories – either one supernova went off at the core of this bubble and pushed gas outward forming what we now call the 'Perseus-Taurus Supershell', or a series of supernovae occurring over millions of years created it over time."
Mapping things in space is a tricky prospect. In two dimensions, it's pretty straightforward, but the third dimension – depth – takes a little more work. We have a number of ways of doing so, but there are gaps in our knowledge, and many uncertainties remain.
To explore the Perseus and Taurus molecular clouds, the researchers used data from Gaia, the European Space Agency's satellite observatory, which has been working since 2013 to map the Milky Way galaxy in three dimensions with the most detail and highest precision achievable. It's one of the most powerful tools we have for helping us understand the architecture – and therefore the history – of our home galaxy... (MORE)