Space

source https://chandra.si.edu/blog/node/719

cross-posted from: https://lemmy.world/post/31469771

Scientists find universe's missing matter while watching fast radio bursts shine through 'cosmic fog'

Half of the universe's ordinary matter was missing — until now.

Astronomers have used mysterious but powerful explosions of energy called fast radio bursts (FRBs) to detect the universe's missing "normal" matter for the first time.

This previously missing stuff isn't dark matter, the mysterious substance that accounts for around 85% of the material universe but remains invisible because it doesn't interact with light. Instead, it is ordinary matter made out of atoms (composed of baryons) that does interact with light but has until now just been too dark to see.

It's easy to think about the creation of the Universe like exploding fireworks: Start with a big bang, and then all the galaxies in the Universe fly out in all directions from some central point.

But that analogy isn't correct. Not only does it falsely imply that the expansion of the Universe started from a single spot, which it didn't, but it also suggests that the galaxies are the things that are moving, which isn't entirely accurate.

It's not so much the galaxies that are moving away from each other – it's the space between galaxies, the fabric of the Universe itself, that's ever-expanding as time goes on. In other words, it's not really the galaxies themselves that are moving through the Universe; it's more that the Universe itself is carrying them farther away as it expands.

A common analogy is to imagine sticking some dots on the surface of a balloon. As you blow air into the balloon, it expands. Because the dots are stuck on the surface of the balloon, they get farther apart.

Though they may appear to move, the dots actually stay exactly where you put them, and the distance between them gets bigger simply by virtue of the balloon's expansion. ... The thing we think of as the "center" of the balloon is a point somewhere in its interior, in the air-filled space beneath the surface.

But in this analogy, the Universe is more like the latex surface of the balloon. The balloon's air-filled interior has no counterpart in our Universe, so we can't use that part of the analogy – only the surface matters.

So asking, "Where's the center of the Universe?" is somewhat like asking, "Where's the center of the balloon's surface?" There simply isn't one. You could travel along the surface of the balloon in any direction, for as long as you like, and you'd never once reach a place you could call its center because you'd never actually leave the surface.

In the same way, you could travel in any direction in the Universe and would never find its center because, much like the surface of the balloon, it simply doesn't have one.

Matt from Standup Maths has an interesting project on the go. He has an opportunity to have some compute time on a lunar rover.

Thanks to its newly tilted orbit around the Sun, the European Space Agency-led Solar Orbiter spacecraft is the first to image the Sun’s poles from outside the ecliptic plane. Solar Orbiter’s unique viewing angle will change our understanding of the Sun’s magnetic field, the solar cycle and the workings of space weather.

Read More From ESA.