Your Neighborhood Astrophysicist is Becoming Discouraged

Lots of astrophysicists these days are becoming discouraged. They are feeling a bit hopeless, thinking of giving up. What are they becoming discouraged about? They are losing their normal sense of optimism because they are not sure they will ever figure out the true identities of dark matter and dark energy. In fact, they are beginning to admit publicly that those names don't really mean anything. According to David Schlegel of Lawrence Berkeley National Laboratory, "The whole name is a placeholder. It’s a placeholder for the description that there’s something funny that was discovered eight years ago now that we don’t understand.” The term "dark" is used only to indicate that it is unknown. Furthermore, scientists are now willing to admit that dark energy and dark matter may not even exist.

There's definitely something screwy going on, however. Dark matter was postulated because galaxies, and galaxy clusters, are spinning much too fast to stay in one piece, unless there's a whole lot of something else there exerting enough gravity to hold these things together. Hence dark matter. Whatever it is, if it even is, "it lies not only outside the visible but also beyond the entire electromagnetic spectrum" (Out There, Richard Panek). And dark energy (the term) was invented to explain why the expansion of the Universe, rather than slowing down as expected due to the influence of all the matter within it, was found to be accelerating. This was discovered by measuring the brightness of a certain class of supernovae...they were farther away, and thus dimmer, than they should have been. Hence dark energy, something that seemed to be countering the effects of gravity.

Hmm, it seems that gravity keeps coming up. There is a third problem that physicists have been trying to solve for decades now, and it also has to do with gravity. Einstein's theories effectively describe how gravity operates with large things like stars and galaxies. Quantum theory effectively describes how gravity works with very small things like electrons and quarks. But when the two, the very big and the very small come together, as in black holes and the beginning of the universe, the two systems of math come up with absurd answers that make no sense. Which bothers physicists very much and which motivates their search for a "theory of everything" that will describe the large and the small in terms of how gravity works.

Now, if you are smart like me, you have noticed that gravity is involved in all three mysteries. That is probably a clue which tells us that there's a problem with our understanding of gravity. The problem apparently is that we do not understand what gravity is. (The word "is" seems to be coming up a bit too often, too. Hmm.)

So, your neighborhood astrophysicist is thinking of giving up on all the dark stuff and pursuing a more promising line of research. I think that would be a shame. I think we should bake them a cake or something, cheer them up. I want to know what gravity is, too.