Twenty years ago, NASA’s orbiting Chandra X-ray Observatory beamed back its stunning “First Light” image of Cassiopeia A – but it’s still been checking back in every now and then.
Here’s how the supernova remnant has shifted and flowed in the two decades since go.nasa.gov/30AaeLr
Black holes are some of the most powerful and fascinating phenomena in our Universe, but due to their tendency to swallow up anything nearby, getting up close to them for some detailed analysis isn’t possible right now.
Instead, scientists have put forward a proposal for how we might be able to model these massive, complex objects in the lab — using holograms.
While experiments haven’t yet been carried out, the researchers have put forward a theoretical framework for a black hole hologram that would allow us to test some of the more mysterious and elusive properties of black holes — specifically what happens to the laws of physics beyond its event horizon.
Ummmn o.o!
How are black holes born? Astrophysicists have theories, but we don’t actually know for certain. It could be massive stars quietly imploding with a floompf, or perhaps black holes are born in the explosions of colossal supernovas. New observations now indicate it might indeed be the latter.
In fact, the research suggests that those explosions are so powerful, they can kick the black holes across the galaxy at speeds greater than 70 kilometres per second (43 miles per second).
“This work basically talks about the first observational evidence that you can actually see black holes moving with high velocities in the galaxy and associate it to the kick the black hole system received at birth,” astronomer Pikky Atri of Curtin University and the International Centre for Radio Astronomy Research (ICRAR) told ScienceAlert.
A black hole is a region of spacetime exhibiting gravitational acceleration so strong that nothing can escape, not even light. These cosmic phenomena are said to form when massive stars collapse at the end of their life cycle. Then, they can continue to grow by absorbing mass from their surroundings, engulfing stars in their path and merging with other black holes.
Wow. The Chandra X-ray Observatory just celebrated its 20th anniversary of being launched into space! It roared into orbit on board the Space Shuttle Columbia on July 23, 1999.
Chandra was a revolution in X-ray astronomy. This high-energy form of light can’t penetrate Earth’s atmosphere, so you have to launch telescopes into space to see it. On top of that, you can’t easily focus X-rays, since they tend to pass right through mirrors. Awkward. So Chandra uses a set of nested, curved sheets of finely shaped metal set almost edge-on to the incoming X-rays. The photons hit the sheets at extremely low angle and graze off it like a rock skipping on water. In this way, the light is gently coaxed into moving in a different direction, so it can be focused this way.
Then again, maybe not.
In a previous post, I explained why quantum mechanics predicts that there are countless versions of you running around in what could be an infinite number of parallel universes.
This time, I’m going to introduce a controversial proposal by MIT physicist Max Tegmark, that uses these parallel universes to argue that you might actually be immortal.
I am going home :3.
Everybody wants a wormhole. I mean, who wants to bother traveling the long-and-slow routes throughout the universe, taking tens of thousands of years just to reach yet another boring star? Not when you can pop into the nearest wormhole opening, take a short stroll, and end up in some exotic far-flung corner of the universe.
There’s a small technical difficulty, though: Wormholes, which are bends in space-time so extreme that a shortcut tunnel forms, are catastrophically unstable. As in, as soon as you send a single photon down the hole, it collapses faster than the speed of light.
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Two researchers at Harvard University, Aavishkar A. Patel and Subir Sachdev, have recently presented a new theory of a Planckian metal that could shed light on previously unknown aspects of quantum physics. Their paper, published in Physical Review Letters, introduces a lattice model of fermions that describes a Planckian metal at low temperatures (Tà 0).
Metals contain numerous electrons, which carry electric current. When physicists consider the electrical resistance of metals, they generally perceive it as arising when the flow of current-carrying electrons is interrupted or degraded due to electrons scattering off impurities or off the crystal lattice in the metal.
“This picture, put forth by Drude in 1900, gives an equation for the electrical resistance in terms of how much time electrons spend moving freely between successive collisions,” Patel told Phys.org. “The length of this time interval between collisions, called the ‘relaxation time,’ or ‘electron liftetime,’ is typically long enough in most common metals for the electrons to be defined as distinct, mobile objects to a microscopic observer, and the Drude picture works remarkably well.”