Despite their ancient ages, some stars orbiting the Milky Way’s central supermassive black hole appear deceptively youthful. But unlike humans, who might appear rejuvenated from a fresh round of collagen injections, these stars look young for a much darker reason.
The universe is still expanding at an accelerating rate, but it may have slowed down recently compared with a few billion years ago, early results from the most precise measurement of its evolution yet suggested Thursday.
The preliminary findings are far from confirmed, but if they hold up, it would further deepen the mystery of dark energy — and likely mean there is something important missing in our understanding of the cosmos.
These signals of our universe’s changing speeds were spotted by the Dark Energy Spectroscopic Instrument, or DESI, which is perched atop a telescope at the Kitt Peak National Observatory in the U.S. state of Arizona.
Scientists may be one step closer to unlocking one of the great mysteries of the universe after calculating that neutron stars might hold a key to helping us understand elusive dark matter.
If you were to throw a message in a bottle into a black hole, all of the information in it, down to the quantum level, would become completely scrambled. Because in black holes this scrambling happens as quickly and thoroughly as quantum mechanics allows. They are generally considered nature’s ultimate information scramblers.
The new BREAD experiment, which was designed to search the cosmos for mysterious dark matter, has returned its first results.
Stephen Hawking and Jacob Bekenstein calculated the entropy of a black hole in the 1970s, but it took physicists until now to figure out the quantum effects that make the formula work.
By Leah Crane
But when it comes to the origin of the Universe, we don’t know what forces are at play. We actually can’t know, since to know such force (or better, such fields and their interactions) would necessitate knowledge of the initial state of the Universe. And how could we possibly glean information from such a state in some uncontroversial way? In more prosaic terms, it would mean that we could know what the Universe was like as it came into existence. This would require a god’s eye view of the initial state of the Universe, a kind of objective separation between us and the proto-Universe that is about to become the Universe we live in. It would mean we had a complete knowledge of all the physical forces in the Universe, a final theory of everything. But how could we ever know if what we call the theory of everything is a complete description of all that exists? We couldn’t, as this would assume we know all of physical reality, which is an impossibility. There could always be another force of nature, lurking in the shadows of our ignorance.
At the origin of the Universe, the very notion of cause and objectivity get entangled into a single unknowable, since we can’t possibly know the initial state of the Universe. We can, of course, construct models and test them against what we can measure of the Universe. But concordance is not a criterion for certainty. Different models may lead to the same concordance — the Universe we see — but we wouldn’t be able to distinguish between them since they come from an unknowable initial state. The first cause — the cause that must be uncaused and that unleashed all other causes — lies beyond the reach of scientific methodology as we know it. This doesn’t mean that we must invoke supernatural causes to fill the gap of our ignorance. A supernatural cause doesn’t explain in the way that scientific theories do; supernatural divine intervention is based on faith and not on data. It’s a personal choice, not a scientific one. It only helps those who believe.
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