We’ve not only had a good few years in terms of space science discoveries, we’ve had a few good decades really. However, with all the new things that we have learned, there are still many fundamental questions that are still outstanding and that scientists are still having difficulty in answering. Here’s 5 of them:
1. What came before the Big Bang? For most physicists, this question is easy to answer as is meaningless. If time began with the Big Bang, then there simply is no before. It’s similar to asking what is South of the South Pole? Physicists have a model that shows how the universe expanded rapidly just after the Big Bang, then eventually slowed again to a normal rate of expansion. But, if we try to see what happened before that, general relativity falls apart. Some experts are suggesting that perhaps time didn’t start with the Big Bang after all, but somehow emerged at some point after the universe had reached a certain level of complexity. Others believe the Big Bang was simply a transition from an earlier era. Another theory is that the universe is just of many in a multiverse. So, it seems we’re no further forward to answering this question now than we were half a century ago.
2. What is dark matter? Astronomers discovered dark matter nearly a century ago. The problem is in trying to prove it exists. Although it’s said to make up more than a quarter of the total mass and energy in the visible universe, no one can say for certain what it really is. At their best guess, scientists figure dark matter to be made up pf weakly interacting particles that can pass through ordinary matter. But so far, they’re yet to prove they’re there. University of Toronto physicist Roberto Abraham says, “It would be nice to know what the dark matter particle is – or even have some reassurance that it is a particle.” So, nowhere with answering this one yet either I’m afraid.
3. Are we alone? There are several hundred billion stars within our galaxy, some of which no doubt have planets orbiting them. And with experts reckoning that there are at least a trillion galaxies in the universe that we can see, it’s quite likely there is life somewhere else out there. The SETI Institute near San Francisco is dedicated to searching for alien life, but so far has come up with nothing. However, senior astronomer at the institute, Seth Shostak, says it’s too soon to tell if there’s life out there as so far have only aimed our telescope at a few thousand stars, but he estimates we’ll find an alien signal within the next 24 years.
4. What is dark energy? Scientists discovered in the 1990’s, through the use of the Hubble Space Telescope, that the galaxies are in fact accelerating away from one another and the force in which is pushing them away is dark energy. Dark energy is said to account for more than two-thirds of the total energy of the visible universe. But so far, trying to prove what dark energy is made up of has been impossible and so still it remains a bit of a mystery.
5. What’s inside a black hole? A black hole is a region of space that has such a strong pull of gravity in which nothing can escape. They are completely shut off from the rest of the world, and if you were to get inside one to see what was there, how would you ever get out again to be able to share it with anyone? The most we can hope for here is to study the event horizon to search for any clues as to what might be inside, hence why the Event Horizon Telescope was built. This network links various telescopes around the world from Chile, Arizona, California, Spain, Hawaii and Antarctica and will soon begin collecting its first batch of data. But, unfortunately (for the moment at least) we’re still no further forward in answering this one either I’m afraid.
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