Top 10 Space Mysteries That Scientists Can't Explain

The multiverse is a fun idea to contemplate, and makes for some imaginative tales. But there may also be truth to the concept! The basic idea is that our universe might be one of many - perhaps even an infinite number. The existence of a multiverse has been proposed not only by philosophers, but also physicists and cosmologists. One suggestion is that it explains how our own universe seems to be fine-tuned for conscious life. In an infinite multiverse, it’s a sure bet that some of them will have the right initial conditions for the evolution of thinking beings. Many scientists are skeptical of the idea however, questioning whether it can ever be proven. Maybe our counterparts in a parallel world know the answer …

There are an estimated 100–400 billion stars in our galaxy, the Milky Way. But one in particular has captured the attention of the scientific community. Known as Tabby’s Star, it’s about 1,470 light-years away in the constellation Cygnus. The star mysteriously dims and brightens over time, and the bizarre light fluctuations have baffled scientists. Several theories have been put forth, but no consensus has been reached. The theories in question range from a cloud of dust orbiting the star to space debris periodically obscuring the light. Some scientists have even speculated that there’s an alien megastructure involved! Maybe in a few years we’ll know the truth. It’s hard to study something so far away.

One of Jupiter’s distinguishing characteristics is undoubtedly its Great Red Spot. While it looks quite small within the context of the entire planet, the spot is actually enormous. The largest storm in the entire solar system, with wind speeds of up to 268 miles per hour, the Great Red Spot is over 10,000 miles wide, larger than the diameter of Earth. Even more fascinating, it’s believed that the storm has been raging for at least three and a half centuries. And yet we know very little about it. We don't really know what caused it, where it draws its incredible energy, or why it’s been going on for so long. Heck, we don’t even know for sure why it’s red!

Dark energy and dark matter make up 95% of the universe. The remaining 5% consists of visible, or baryonic, matter. The only thing is, there should be way more baryonic matter around than there actually is. Studies have found a serious discrepancy in the amount of baryonic matter that existed after the Big Bang and the amount that’s around today in the observable universe. In fact, over half of this matter just seems to be missing! So what the heck happened to the rest of it? Scientists do have theories, believing that some of this matter exists as difficult-to-detect hot strands between galaxy pairs, or outside dark matter haloes. But research continues as measurements improve.

It’s perhaps the biggest question we all want an answer for. Are we alone in the universe? Mind you, extraterrestrial life could be as simple as a single-celled organism. But the odds do seem to favor the idea of intelligent life out there somewhere too. Back in 1961, astronomer Frank Drake and his colleagues presented the Drake Equation, which attempts to estimate the number of communicative alien civilizations in our galaxy. Their original estimates were 1,000 to 100,000,000! Even conservative estimates often land in the thousands. Just imagine how many more could be out there in the wider universe beyond the Milky Way!

There are many things we don’t know about the universe we inhabit. For example, its shape, although scientists think that it’s probably flat. More interestingly, we don’t know its true size. Ever since the Big Bang 13.8 billion years ago, space has been constantly expanding. In fact, space may expand faster than light can traverse it - meaning that we will never observe parts of the universe beyond certain points. What we do know is the size of the observable universe, comprising objects whose light has had time to reach our Solar System. And it’s big: 93 billion light years across. The entire universe may be 250 times bigger than that. Or it may simply stretch into infinity.

We have an idea about how the universe began - with the Big Bang. But how will it end? The answer all depends on the universe’s density. If the universe is dense enough to counter expansion, the universe will contract in a Big Crunch. Some believe that afterwards, a Big Bounce will occur, with a new Big Bang emerging from the singularity. In contrast, the Big Rip theorizes that the universe will continue to expand until tearing itself apart. The leading theory is the Big Freeze, in which continued expansion makes star formation impossible, and the universe exhausts its finite source of energy, cooling to absolute zero.

It’s pretty astounding to think that dark matter and dark energy make up most of the universe, and we don’t really know anything about them. We know that dark matter exists due to certain gravitational effects, and dark energy thanks to the fact that the universe’s expansion is accelerating. But what are they? One theory posits that dark energy is a fundamental energy intrinsic to space itself. Dark matter, on the other hand, may consist of as-yet-undiscovered subatomic particles. But really, these are just our best guesses. Since dark matter doesn’t seem to interact with the electromagnetic field, we have no way of directly observing it!

There’s a strong scientific consensus that our universe began with what we call the Big Bang. 13.8 billion years ago, a singularity - a point of infinite density - expanded, sending forth matter and energy. But that just raises more questions. Where did all that matter and energy come from? Since spacetime was created with the Big Bang, maybe it doesn’t make sense to ask what came before the singularity. But we can ask: why is there something rather than nothing? One possible answer is that the universe is cyclical - moving between Big Bangs and Big Crunches. Even that, though, doesn’t really answer all our questions.

When we ask why there’s something rather than nothing, it can also be a way of asking: why are we here? How are we here? Why were the initial conditions of the universe such that life could arise? How did atoms come together and start thinking about themselves? Life began on Earth about four billion years ago. Some scientists think that asteroids and comets brought the necessities for life to our planet. Believers in panspermia hold that life originated elsewhere, and was brought to Earth via the same means. However, this just defers the question. How does life form? So far scientists have been unable to create new life from scratch … although with time, who knows?