The Big Bang still seems like the most reasonable explanation. But many are rethinking what else we know, based on “stubborn problems with dark matter, dark energy, and cosmic expansion”:
We know almost nothing about dark matter and dark energy, which together make up more than 95 percent of the total energy in existence today. We don’t understand how the universe’s protons, electrons, and neutrons could have survived the aftereffects of the Big Bang. In fact, everything we know about the laws of physics tells us that these particles should have been destroyed by antimatter long ago. And in order to make sense of the universe as we observe it, cosmologists have been forced to conclude that space, during its earliest moments, must have undergone a brief and spectacular period of hyperfast expansion — an event known as cosmic inflation. Yet we know next to nothing about this key era of cosmic history.
It’s possible that these puzzles are little more than loose ends, each of which will be resolved as cosmologists continue to investigate our universe. But so far, these problems have proven to be remarkably stubborn and persistent. With the goal of identifying the individual particles that make up dark matter, scientists have designed and built a series of impressive experiments — yet no such particles have appeared. …Dan Hooper, “Is the Big Bang in crisis?” at Astronomy
Our physics color commentator Rob Sheldon offers,
This is a level-headed assessment that the problems of Dark Matter, Dark Energy and the Hubble tension (74 vs 67 km/s-pc) are all pointing to a problem with the “Lambda-CDM” model of the Big Bang, and in particular the first few seconds.
This is precisely where I argue we needed to look. We won’t find DM in our liquid xenon tanks, we won’t find DE in our supernovae calculations, we won’t find inflation in our “baryonic acoustic modulations” because all these things are secondary corrections to a BB model that fundamentally is failing. Time to reset and rebuild that model from the ground up.
I don’t expect the world to be falling over itself to take Hooper’s advice. There’s this thing that Lakatos called a “degenerative research programme” that like the coelacanth, doesn’t know when to go extinct. But it is becoming clear to everyone that: (a) cosmology behaves as a degenerative research programme; and (b) the problem lies in the BB model first put together in the 50’s and 60’s.
As these towering paradigms fall, taking other giants out of the canopy, there’s more sunlight for us, down here in the weeds. It’s going to be a great century for doing science!
See also: The Big Bang: Put simply,the facts are wrong.