Jun 28, 2023 05:39 PM
(This post was last modified: Jun 29, 2023 01:26 PM by C C.)
An enormous gravity ‘hum’ moves through the universe
https://www.quantamagazine.org/an-enormo...-20230628/
INTRO: Astronomers have found an extra-low hum rumbling through the universe.
The discovery [...] shows that extra-large ripples in space-time are constantly squashing and changing the shape of space. These gravitational waves are cousins to the echoes from black hole collisions first picked up by the Laser Interferometer Gravitational-Wave Observatory (LIGO) experiment in 2015. But whereas LIGO’s waves might vibrate a few hundred times a second, it might take years or decades for a single one of these gravitational waves to pass by at the speed of light.
The finding has opened a wholly new window on the universe, one that promises to reveal previously hidden phenomena such as the cosmic whirling of black holes that have the mass of billions of suns, or possibly even more exotic (and still hypothetical) celestial specters.
“It’s beautiful,” said Chiara Caprini, a theoretical physicist at the University of Geneva and CERN in Switzerland who was not directly involved in the work. “A new era in the observation of the universe has opened up.”
The results come from studies that stretch back more than a decade by four teams based in the U.S., Europe, Australia and China. Today, in a coordinated data release, the teams present evidence for a background “hum” of gravitational waves that were detected by tracking changes in the impossibly regular beats of objects called pulsars... (MORE - details)
We might have accidentally killed the only life we ever found on Mars nearly 50 years ago
https://bigthink.com/hard-science/accide...life-mars/
KEY POINTS: Life may have been discovered on Mars almost 50 years ago, but it could have been unintentionally destroyed. This theory arises from the ambiguous results of life detection experiments conducted by NASA's Viking landers in the mid-1970s.
The Viking landers identified small amounts of chlorinated organics, initially believed to be contamination from Earth. However, subsequent missions have verified the presence of native organic compounds on Mars, although in a chlorinated form.
Life on Mars could have adapted to the arid environment by existing within salt rocks and absorbing water directly from the atmosphere. The Viking experiments, which involved adding water to soil samples, might have overwhelmed these potential microbes, leading to their demise... (MORE - details)
Could the expanding Universe truly be a mirage?
https://bigthink.com/starts-with-a-bang/...se-mirage/
KEY POINTS: In a new paper just accepted for publication in the journal Classical & Quantum Gravity, theoretical physicist Lucas Lombriser showed that one can reformulate the Universe to not be expanding, after all. Instead, you can rescale your coordinates so that all of the fundamental constants within your Universe change in a specific fashion over time, mimicking cosmic expansion in an actually non-expanding Universe.
But could this approach actually apply to our real Universe, or is it a mere mathematical trick that the observations we already have rule out? The smart money is on the latter option... (MORE - details)
https://www.quantamagazine.org/an-enormo...-20230628/
INTRO: Astronomers have found an extra-low hum rumbling through the universe.
The discovery [...] shows that extra-large ripples in space-time are constantly squashing and changing the shape of space. These gravitational waves are cousins to the echoes from black hole collisions first picked up by the Laser Interferometer Gravitational-Wave Observatory (LIGO) experiment in 2015. But whereas LIGO’s waves might vibrate a few hundred times a second, it might take years or decades for a single one of these gravitational waves to pass by at the speed of light.
The finding has opened a wholly new window on the universe, one that promises to reveal previously hidden phenomena such as the cosmic whirling of black holes that have the mass of billions of suns, or possibly even more exotic (and still hypothetical) celestial specters.
“It’s beautiful,” said Chiara Caprini, a theoretical physicist at the University of Geneva and CERN in Switzerland who was not directly involved in the work. “A new era in the observation of the universe has opened up.”
The results come from studies that stretch back more than a decade by four teams based in the U.S., Europe, Australia and China. Today, in a coordinated data release, the teams present evidence for a background “hum” of gravitational waves that were detected by tracking changes in the impossibly regular beats of objects called pulsars... (MORE - details)
We might have accidentally killed the only life we ever found on Mars nearly 50 years ago
https://bigthink.com/hard-science/accide...life-mars/
KEY POINTS: Life may have been discovered on Mars almost 50 years ago, but it could have been unintentionally destroyed. This theory arises from the ambiguous results of life detection experiments conducted by NASA's Viking landers in the mid-1970s.
The Viking landers identified small amounts of chlorinated organics, initially believed to be contamination from Earth. However, subsequent missions have verified the presence of native organic compounds on Mars, although in a chlorinated form.
Life on Mars could have adapted to the arid environment by existing within salt rocks and absorbing water directly from the atmosphere. The Viking experiments, which involved adding water to soil samples, might have overwhelmed these potential microbes, leading to their demise... (MORE - details)
Could the expanding Universe truly be a mirage?
https://bigthink.com/starts-with-a-bang/...se-mirage/
KEY POINTS: In a new paper just accepted for publication in the journal Classical & Quantum Gravity, theoretical physicist Lucas Lombriser showed that one can reformulate the Universe to not be expanding, after all. Instead, you can rescale your coordinates so that all of the fundamental constants within your Universe change in a specific fashion over time, mimicking cosmic expansion in an actually non-expanding Universe.
But could this approach actually apply to our real Universe, or is it a mere mathematical trick that the observations we already have rule out? The smart money is on the latter option... (MORE - details)