One way of measuring the Universe’s expansion history involves going all the way back to the first light we can see, when the Universe was just 380,000 years old. The other ways don’t go backwards nearly as far, but also have a lesser potential to be contaminated by systematic errors. (European Southern Observatory)

What Astronomers Wish Everyone Knew About Dark Matter And Dark Energy

Among the general public, people compare it to the aether, phlogiston, or epicycles. Yet almost all astronomers are certain: dark matter and dark energy exist. Here’s why.

If you go by what’s often reported in the news, you’d be under the impression that dark matter and dark energy are houses of cards just waiting to be blown down. Theorists are constantly exploring other options; individual galaxies and their satellites arguably favor some modification of gravity to dark matter; there are big controversies over just how fast the Universe is expanding, and the conclusions we’ve drawn from supernova data may need to be altered. Given that we’ve made mistaken assumptions in the past by presuming that the unseen Universe contained substances that simply weren’t there, from the aether to phlogiston, isn’t it a greater leap-of-faith to assume that 95% of the Universe is some invisible, unseen form of energy than it is to assume there’s just a flaw in the law of gravity?

The answer is a resounding, absolute no, according to almost all astronomers, astrophysicists, and cosmologists who study the Universe. Here’s why.