Cosmology today is faced with profound riddles, as I explore in my book Edge of the Universe. Although we know certain facts better than ever, such as the age of the universe, ascertained to be 13.8 billion years old, many deep mysteries remain. Foremost among these is what makes up dark matter, the invisible glue holding galaxies together, and dark energy, what pushes them apart and causes the cosmos to accelerate.
Searches in the Large Hadron Collider (LHC) and deep underground for potential dark matter particles have turned up empty. With the reboot of the LHC this year, perhaps such dark matter particles will be found, in the way that the Higgs particle was discovered several years ago. (More about the LHC is described in my book Collider.)
Dark energy presents an even more perplexing conundrum, as we don’t know of substances in space that counteract gravity and cause acceleration. If dark energy is strong enough it could eventually tear the universe apart in a cosmic catastrophe called the Big Rip. Other theories of cosmic fate imagine cycles of time. The jury is still out on what will be the destiny of the universe.
Yet another enigma concerns the question of what lies beyond the observable universe. Could our universe comprise just one bubble in an endless multiverse? Edge of the Universe explores these cosmic questions and more.