Tag Archives: cosmology

Existential Cosmology: Embracing the Possibility of the Universe’s Disappearance

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Billions, perhaps trillions of years from now, long after the sun has swallowed the Earth, cosmologists predict the universe will end. Some people wrestle with whether they are likely to collapse under the weight of the Big Crunch or become an infinitely empty Big Freeze that will continue to expand forever. Some believe that the end of our universe will be determined by a mysterious energy that rips the universe apart.

But there is a more immediate cataclysm that may already be heading towards us at the speed of light. They call it “big sip.”

The slurp in question begins with a quantum fluctuation, causing the bubble to roll through space like a cosmic tsunami, obliterating everything in its path. We should take this possibility seriously, says John Ellis of King's College London. In fact, the question is not so much if this apocalypse will happen, but when. “It could be happening as we speak,” he says.

Theorists like Ellis are actually surprised that such a catastrophe has not yet occurred in the observable universe. But rather than take our precarious existence for granted, they use the obvious fact that we are still here as a tool. The idea is that some weird physics is protecting us.

This kind of existential cosmology also helps physicists filter through the myriad models of the universe, and could tell us how the universe began in the first place. “Maybe you need something to stabilize it. [the universe]And it could be new physics.'' arthu rajanti…

Source: www.newscientist.com

Our universe is so empty that it defies the laws of cosmology.

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Ryan’s will.Klaus Wedfeld/Getty Images

Have you ever felt like you’re stuck in a hole? Newsflash: Yes, you are. Astronomers call it a “local hole,” but that’s quite an understatement. It’s vast, it’s gigantic, it’s gigantic – but the truth is, adjectives are inapplicable when it comes to this expanse of nothingness. It is the largest cosmic cavity known to us, spanning 2 billion light years. Our galaxy happens to be near its center, but the problem with this hole is not that it poses any immediate danger, but rather that it shouldn’t exist.

The question is whether one of our most firmly held beliefs about the universe is true. This assumption, known as the cosmological principle, states that matter in the universe should be uniformly distributed on the largest scale. It is the foundation upon which much of modern cosmology is built. If the void were real, the stone might have collapsed.

Because of this, few people dared to believe that the void could be real. But as evidence has grown in recent years, astronomers have moved from suspicion to reluctant acceptance. They discovered other similarly huge structures. So now the question is being asked with increasing urgency: If we are indeed living in a vacuum, do we need to significantly revise our cosmological model? That may include rethinking the nature of gravity, dark matter, or both.

The idea that the universe has the same properties from beginning to end can be traced back at least to Isaac Newton. He claimed that the motion of stars and planets could be explained…

Source: www.newscientist.com

Cosmology: A Simple Explanation

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The US Department of Energy defines cosmology as the study of the origin and development of the entire universe. It is divided into observational and physical branches, with observational cosmology using telescopes and instruments for direct evidence of the universe’s structure and evolution, while physical cosmology studies the universe’s development and the physics that created it.

The origins of cosmology can be traced back to the 1500s when Copernicus observed the Earth’s revolution around the sun, and later in the 1600s when Newton discovered that objects in space follow the same physical laws as those on Earth. In the early 20th century, Einstein’s theory of relativity provided a model of space-time, leading to modern physical cosmology.

Modern cosmologists believe that dark matter and dark energy make up most of the universe, with dark energy accounting for more than two-thirds, and dark matter for a quarter of the universe. The study of cosmology encompasses various fields such as big bang, formation of large-scale structures, big bang nucleosynthesis, cosmic microwave background, dark matter, and gravitational waves.

Scientists estimate that there are 2 trillion galaxies in the universe, and the earliest light to reach Earth was 13.77 billion years ago. The total energy balance of the universe consists of about 5 percent ordinary matter, 27 percent dark matter, and 68 percent dark energy.

The US Department of Energy’s Office of Science supports cosmology research through its Nuclear Physics and High Energy Physics programs, which focus on the study of particles, dark matter, and dark energy to further understand the universe.

Source: scitechdaily.com