Gravity

Tag archives for Gravity

The Universe isn’t a static place. Although the laws of nature (physics, chemistry, biology, etc.) don’t appear to change over time, everything in the Universe appears to evolve, and changes over time. One of the simplest ways that this happens is through Hubble expansion. General relativity tells us how the Universe expands, and more specifically,…

Dark Matter: Is it right in front of us?

Last year, I had just finished my Ph.D. studies, and had moved to Madison, WI to teach introductory physics at the University of Wisconsin. I was working on this paper, and when I submitted it, I got a phone call from New Scientist magazine’s space division. Fast-forward two weeks, and I find this article online,…

One of the perks of being a postdoc at a place like the University of Arizona, one of the top places in the US for astronomy, is that we get a number of really interesting visitors. Today we got paid a visit by Tommaso Treu, an astronomer at UC Santa Barbara. He spoke to us…

MOND vs. Dark Matter

The first serious advocate of modifying Newton’s laws instead of postulating unseen (or dark) matter was Moti Milgrom, from whom today a new article appears on the astrophysics preprint archives. In particular, Milgrom asserts the following: MOND predictions imply that baryons alone accurately determine the full field of each and every individual galactic object. These…