The next big breakthrough in cosmology is on the "dark side" says renowned theoretical physicist Stephen Hawking.
"The missing link in cosmology is the nature of dark matter and dark energy," Hawking said Tuesday night at California Institute of Technology, where he lectured on the origin of the universe.
After giving a brief historical background on relativistic physics and cosmology, Hawking discussed the idea of a repeating Big Bang. He noted that in the 1980s, he and physicist Roger Penrose proved the universe could not "bounce" when it contracted, as had been theorized.
"It has been a glorious time to be alive and doing research in theoretical physics," Hawking said. "Our picture of the universe has changed a great deal in the last 50 years and I'm happy if I have made a small contribution. The fact that we human beings, who are ourselves mere collections of fundamental particles of nature, have been able to come this close to an understanding of the laws governing us and our universe is a great triumph."
Dark matter and dark energy are one of scientists greatest mysteries as dark matter can't be seen or felt directly, but scientists presuppose its existence because its gravity can explain what holds spiral galaxies together.
Hawking then went on to cited data from the European Space Agency's Planck space telescope which shows "that normal matter is only 5% of the energy density of the known universe; 27% is dark matter, 68% is dark energy." Physicists believe dark energy could explain why the universe is expanding at an ever-growing rate instead of collapsing under its own gravity.
"There have been searches for dark matter, but so far no results," Hawking said.
Hawking has been battling the debilitating neurological disorder amyotrophic lateral sclerosis, also known as Lou Gehrig's disease, for 50 years.
