Albert Einstein also predicted the existence of something called gravitational waves. He did this in his theory of general relativity in 1916, and the study still continues today.
What is a gravitational wave? Gravitational waves are ripples in the curvature of space-time itself, which propagate as waves away from the source of gravity. These sources are large bodies of mass, like a neutron star or a black hole.
We have seen indirect evidence of gravitational waves, but we still have not directly observed gravitational waves. In March 2014 however, an image produced by the Harvard-Smithsonian Center for Astrophysics appears to show evidence of the waves existence around the time of the big bang! Some further analysis is required before this conclusion can be made however.
Gravitational waves can be very useful in astrophysics. They can be used to make observations and measurements of very large objects, like black holes. The nice thing about gravitational waves is they appear to be unaltered by matter in the path of propagation. This means there is much less noise in detected signals, compared to traditional methods of measurement.
Ok. Thanks for the link! It’s really interesting. I hope we find out what matter and dark energy are in the future.
Although they sound similar, black holes and dark matter are different. A black hole is formed when a very big star at the end of its life shrinks down to an extremely dense object with a very strong gravitational pull. That pull is so strong that even light can’t escape. So black holes have a high concentration of gravity in one spot. Dark matter is material that is spread out across the universe. It has gravity but is unlike anything we’ve seen before. This link has more information on dark matter: https://spaceplace.nasa.gov/dark-matter/en/
Do black holes have something to do with “dark matter”? Just a side thought.
Wow! That is awesome! Thanks Mrs. Aurora. I’m excited to check out the astronomycast website.
Yes indeed! Black holes spin. Remember that black holes started out as a stars. Our star (the sun) and all other stars rotate. However, they rotate at different rates.
Not only do black holes rotate, but objects also rotate around them. Object spiral around black holes as they fall to their destruction. Also, it is still possible for objects to orbit black holes.
We do indeed detect black holes by their effect on matter that both falls into them and by the matter circling around them.
Yes you can learn more here: https://en.wikipedia.org/wiki/Rotating_black_hole
Also, have you listened to any of the Astronomy Cast shows? http://www.astronomycast.com/
Wait, black holes SPIN??? I though they just sat in space waiting for something to fall into it. Can you find a black hole if something is spinning around it, and is that why things being pulled towards it spiral in? Thanks, Sasha
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Reminds me of that crazy cat circle toy… XD