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Category: cosmology – Page 450

Will the Great Attractor Destroy Us?

Somewhere, in the deepest reaches of the cosmos, far from the safe confines of our home galaxy, the Milky Way, lies a monster. Slowly, inevitably, it is pulling. Over the course of billions of years, it draws us and everything near us closer to it. The only force that acts over such immense distance scales and through cosmic periods of time is gravity, so whatever it is, it’s massive and unrelenting.

We call it the Great Attractor, and until recently, its true nature has been a complete mystery. Note that it’s still a mystery, just not a complete one.

The Great Attractor was first discovered in the 1970s when astronomers made detailed maps of the Cosmic Microwave Background (the light left over from the early universe), and noticed that it was slightly (and “slightly” here means less than one one-hundredth of a degree Fahrenheit) warmer on one side of the Milky Way than the other — implying that the galaxy was moving through space at the brisk clip of about 370 miles per second (600 km/s).

Even though astronomers could measure the rapid velocity, they couldn’t explain its origin.

Could Dark Energy Be Caused By A Reaction To What’s In The Universe? (Synopsis)

“Another very good test some readers may want to look up… is the Casimir effect, where forces between metal plates in empty space are modified by the presence of virtual particles.” –Gordon Kane

If you ask what the zero-point energy of space itself is, you can sum up all of the quantum fluctuations you can that arise in quantum field theory, and arrive at an absurd answer: 120 orders of magnitude greater than the observed. Yet if you assume that there’s an incredible cancellation and you get exactly zero, that removes the one thing our Universe needs to explain its expansion: dark energy.

Did the LIGO gravitational waves originate from primordial black holes?

Binary black holes recently discovered by the LIGO-Virgo collaboration could be primordial entities that formed just after the Big Bang, report Japanese astrophysicists.

If further data support this observation, it could mark the first confirmed finding of a primordial black hole, guiding theories about the beginnings of the universe.

In February, the LIGO-Virgo collaboration announced the first successful detection of gravitational waves.

Astronomers Find Black Holes Do Not Absorb Dark Matter

There’s the common notion that black holes suck in everything in the nearby vicinity by exerting a strong gravitational influence on the matter, energy, and space surrounding them. But astronomers have found that the dark matter around black holes might be a different story. Somehow dark matter resists ‘assimilation’ into a black hole.

About 23% of the Universe is made up of mysterious dark matter, invisible material only detected through its gravitational influence on its surroundings. In the early Universe clumps of dark matter are thought to have attracted gas, which then coalesced into stars that eventually assembled the galaxies we see today. In their efforts to understand galaxy formation and evolution, astronomers have spent a good deal of time attempting to simulate the build up of dark matter in these objects.

Most of the universe may be trapped inside of ancient black holes

(A computer simulation of a black hole. NASA, ESA, and D. Coe, J. Anderson, and R. van der Marel (STScI))

In case you haven’t heard, there is a very, very big problem with the universe: About 80% of all of the stuff inside it is missing.

Astronomers call this material “dark matter.” They know it’s out there because its huge mass tugs on and shapes galaxies, but no one has ever detected the material itself. Aside from exerting a gravitational pull, dark matter doesn’t seem to interact with stars, planets, dust, atoms, subatomic particles, or any other “normal” matter as we know it. It’s essentially invisible.

Physicists Say They’ve Figured out How Spacecraft Could Make It Through a Wormhole

A new paper asserts that a physical body might be able to pass through a wormhole in spite of the extreme tidal forces that are at play.

A physical object, such as a person or a spacecraft, could theoretically make it through a wormhole in the centre of a black hole, and maybe even access another universe on the other side, physicists have suggested.

In what looks like the logical extension of the plot of Interstellar – where astronauts try to hunt down another universe after the catastrophic effects of climate change destroy Earth – physicists have modelled what would happen to a chair, a scientist, and a spacecraft, if each one ended up inside the spherical wormhole of a black hole.