Ask Ethan: If the Universe is expanding, why aren’t we? (Synopsis) [Starts With A Bang]

“The Universe is expanding the way your mind is expanding. It’s not expanding into anything you are just receiving less dense.” -Katie Mack

It’s a point of scientific beauty that we’ve not only been in a position to decide that the Universe is expanding, but that we’ve been able to measure the price of expansion so extremely properly. To greater than 90% uniformity, we’ve determined the expansion price in all directions and going back billions of years, enabling us to determine what’s in the Universe, how that is changed more than time, and what its fate is. It is one particular of the most exceptional achievements of modern science more than the final 100 years.

A plot of the apparent expansion rate (y-axis) vs. distance (x-axis) is consistent with a Universe that expanded faster in the past, but is still expanding today. This is a modern version of, extending thousands of times farther than, Hubble's original work. Image credit: Ned Wright's cosmology tutorial, with data current as of 2015.

A plot of the apparent expansion rate (y-axis) vs. distance (x-axis) is consistent with a Universe that expanded faster in the previous, but is still expanding nowadays. This is a modern version of, extending thousands of occasions farther than, Hubble’s original function. Image credit: Ned Wright’s cosmology tutorial, with information current as of 2015.

But even though the distant galaxies are all expanding away each from us and from one one more, not almost everything in the Universe is expanding. Person galaxy clusters remain bound galaxies do not grow planetary orbits remain continual stars, planets, humans and even atoms stay the exact same size. However, the fabric of the Universe itself nevertheless continues to expand.

The orbits of the planets in the TRAPPIST-1 system are unchanging with the expansion of the Universe, due to the binding force of gravity overcoming any effects of that expansion. Image credit: ESO / M. Gillon et al.

The orbits of the planets in the TRAPPIST-1 method are unchanging with the expansion of the Universe, due to the binding force of gravity overcoming any effects of that expansion. Image credit: ESO / M. Gillon et al.

Why is this the case? Why do not these smaller-scale objects expand along with the fabric of the Universe, although every thing else does? Locate out on this week’s Ask Ethan!

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