By Jonny Lupsha, Wondrium Staff Writer
Radiation left over from the Big Bang is still visible in old TV static. It’s also all around us and can be detected throughout outer space. A senior scientist at Fermilab explains.
Approximately 380,000 years after the Big Bang, space cooled enough to sustain atoms. Around this time, cosmic microwave background radiation (CMB) became detectable—it just had to wait around long enough for scientists who would be able to detect it. An estimated 14 billion years later, scientists realized that 1% of old television static was CMB.
CMB is all around us here on Earth as well as outer space, where it exists at a chilly temperature of about -455 degrees Fahrenheit. Dr. Don Lincoln, Senior Scientist at Fermi National Accelerator Laboratory, explained the phenomenon in a pair of exclusive interviews with The Great Courses.
A Bath of Radio Waves
“The longest-lived remnant of the Big Bang is amazing,” Dr. Lincoln said. “It is this bath of radio waves in which we live. [With] the Big Bang, of course, the universe was smaller and hotter and it was literally a red hot fireball, but it’s been 14 billion years and the universe has been expanding and cooling and that fireball is no longer red hot.”
Something that hot still radiates radio waves—CMB. Although the universe is still expanding and cooling, Dr. Lincoln said that it’s happening over such a long period of time that it won’t affect CMB in our lifetimes. In fact, it may take millions of years for it to drop a few more degrees.
How was CMB discovered? Dr. Lincoln said that two scientists at Bell Labs—Arno Penzias and Robert Wilson—were interested in looking at radio signals in space; so, they prepared a radio telescope to further their interests in astronomy. To calibrate it, they pointed it at what they believed was an empty point in space and they found a hiss.
Assuming it was a mechanical failure, the scientists inspected the telescope and evicted some pigeons and cleaned their droppings. The hiss remained, so they called scientists at Princeton who had been searching for CMB. The Princeton scientists realized they’d been scooped and Penzias and Wilson won the Nobel Prize for their discovery.
The Present and Future of CMB
If CMB is all around us, one would think it affects us somehow. However, Dr. Lincoln said there’s no cause for concern.
“Indirectly, or historically, it affects us because CMB is significantly connected to the laws of physics when the universe was young,” he said. “If the CMB were radically different, the universe would be radically different and we might not be here, but day to day it doesn’t make any difference at all.”
CMB has been with us for most of the universe’s existence. It originated 14 billion years ago and has cooled to remarkably low temperatures as the universe has continued expanding. Dr. Lincoln explained that it isn’t going anywhere, either.
“If we go back to when humanity first diverged from whatever great ape we diverged from, if we’d had a telescope there and looked out at the CMB, it would be indistinguishable from right now, so it was 100,000 or 200,000 years ago; in that time scale, it’s not changing,” he said. “When the light from the CMB was emitted, CMB was about 3,000 degrees Centigrade, or Kelvin, and is now 2.7 degrees Kelvin.”
“So it’s going, it’s expanding. If we stuck around another couple billion years, it wouldn’t be 2.7 degrees, it would be 2.5 degrees or something like that.”
That’s a very minor or incremental change. Not only has CMB been around for almost the entire history of the universe, but it seems as though it’s here to stay.
Edited by Angela Shoemaker, Wondrium Daily
Dr. Don Lincoln contributed to this article. Dr. Lincoln is a Senior Scientist at Fermi National Accelerator Laboratory (Fermilab). He is also a Guest Professor of High Energy Physics at the University of Notre Dame. He received his PhD in Experimental Particle Physics from Rice University.