Lawrence Krauss on "Seeing" the Early Universe
Theoretical physicist and cosmologist Lawrence M. Krauss spoke at CSICon 2016 about scientists' attempt to look back in time to the beginning of our universe.
At a 2016 convention hosted by the Committee for Skeptical Inquiry, theoretical physicist Lawrence M. Krauss spoke about scientists' attempts to look back to when the universe was just fractions of a second old. A few highlights from Krauss' talk are listed below, and his full presentation can be seen at the bottom of this article.
Inflation and the Universe’s “Baby Picture”
The Cosmic Microwave Background radiation (CMB) is the oldest visible light in the universe. According to Inflationary Cosmology, the CMB is essentially the afterglow radiation that was produced when the nascent universe rapidly inflated when it was some 380,000 years old.
“[The universe] went from the size of an atom to the size of a basketball in a billionth of a billionth of a billionth of a billionth of a second,” Krauss said.
Before inflation, the universe was extremely small, hot and dense. It was governed by quantum mechanics, and everything was in flux.
“When Inflation happens, all those quantum fluctuations get frozen in,” Krauss said, noting that there were tiny variations, or “lumps,” in temperature across the CMB that became the spots where galaxies and other matter formed. “[Those fluctuations] later manifest themselves in density, in matter.”
The CMB effectively confirms the Big Bang Theory — the radiation pattern looks exactly like what scientists in the mid-20th century predicted when they first theorized that the universe was once a very small, dense place.
Scientists are now trying to look farther back in time, well beyond the CMB.
“We can never see back earlier than [the CMB], and by ‘see’ I mean look with light,” Krauss said. “We have to use something that interacts much more weakly than light.”
Instead of light, scientists are using gravity to look back on the early universe.
Albert Einstein’s general theory of relativity first predicted the existence of gravitational waves, which, in simplified terms, are ripples in the fabric of spacetime caused by the acceleration of objects.
The theory of inflation predicts that the early universe would have produced certain kinds of gravitational waves. If scientists one day find evidence of these particular gravitational waves, we’d be able to ‘see’ the universe when it was just a fraction of a second old – “essentially at the Big Bang,” Krauss said.
In September 2015, scientists first detected gravitational waves disrupting spacetime. The waves came from the collision of two black holes some 1.3 billion light years away, but they were extremely hard to detect – the spacetime “wobbling” generated by the waves was so subtle that it was thousands of times smaller than the nucleus of an atom.
The video below describes how scientists at the Laser Interferometer Gravitational Wave Observatory (LIGO) first directly detected the waves in 2015.
Eternal Inflation and Multiple Universes
“If we can show that inflation happened, and we can measure the characteristics of inflation, then we know something very interesting,” Krauss said, referring to the idea of eternal inflation.
Eternal inflation suggests that, in extremely simplified terms, inflation caused the universe to expand at different rates in different places, and this gave rise to an infinite number of bubble universes. This process, according to some theorists, could go on forever.
What’s more, the laws of physics could be unique in each bubble universe. Some universes might not even have galaxies at all.
“You’ll never see these universes because they’re expanding away from us faster than light,” Krauss said. “It sounds like it’s metaphysics. But if we could measure the properties of inflation, we might be able to measure grand unification and understand particle physics, and understand those properties and prove that inflation was eternal. And if that’s the case, we will know that there must be other universes out there.”
Although we’ll never be able to see these other universes, scientists would theoretically be able to confirm their existence through indirect experiments.
“It will be like being in 1905 when Einstein first showed that atoms existed in his Ph.D. thesis,” Krauss said. “No one ever thought you’d see an atom. So we’ll turn this metaphysical explanation into physics. And that’s the beauty of science.”
Swipe right to make the connections that could change your career.
Swipe right. Match. Meet over coffee or set up a call.
No, we aren't talking about Tinder. Introducing Shapr, a free app that helps people with synergistic professional goals and skill sets easily meet and collaborate.
It's up to us humans to re-humanize our world. An economy that prioritizes growth and profits over humanity has led to digital platforms that "strip the topsoil" of human behavior, whole industries, and the planet, giving less and less back. And only we can save us.
- It's an all-hands-on-deck moment in the arc of civilization.
- Everyone has a choice: Do you want to try to earn enough money to insulate yourself from the world you're creating— or do you want to make the world a place you don't have to insulate yourself from?
Eight-dimensional octonions may hold the clues to solve fundamental mysteries.
- Physicists discover complex numbers called octonions that work in 8 dimensions.
- The numbers have been found linked to fundamental forces of reality.
- Understanding octonions can lead to a new model of physics.
Upload your mind? Here's a reality check on the Singularity.
- Though computer engineers claim to know what human consciousness is, many neuroscientists say that we're nowhere close to understanding what it is, or its source.
- Scientists are currently trying to upload human minds to silicon chips, or re-create consciousness with algorithms, but this may be hubristic because we still know so little about what it means to be human.
- Is transhumanism a journey forward or an escape from reality?
SMARTER FASTER trademarks owned by The Big Think, Inc. All rights reserved.