Proxima b still a mystery, but has potential to sustain life
Proxima Centauri b, one of about 3,500 discovered exoplanets, has captured the eyes of scientists because it is the first of its kind close enough to Earth for them to potentially research the surface.
“The only thing that makes this unique is it’s close,” said Andy Hollerman, Ph.D., an astronomy professor at the University of Louisiana at Lafayette. “This is grandma’s house; this is down the road a piece, but it’s not that far.”
Proxima b is 4.2 light years away from Earth. It orbits its star, Proxima Centauri, in the “habitable zone,” which means it is in the right position to maintain liquid water — and possibly life.
This potential life, however, would likely be different from humans, Hollerman said. Proxima Centauri is a red star, which means it burns half as hot as our sun, gives off different types of radiation and produces mostly infrared light. Hollerman said these factors would cause life forms to develop differently from humans.
If life isn’t on the planet, “it might be like Mars, where at one time it had it, but it doesn’t have it now,” Hollerman said.
Proxima b and its star also have a longer lifespan than Earth and the sun because red stars have slower burn rates, Hollerman said. The planet will have more time to develop, he said, and it may lead to a more advanced society there than people could accomplish on Earth.
Scientists are still searching for ways to find definitive proof the planet can sustain life. Hollerman said a probe would be needed to find proof, but the science is still a long way from anything capable of traveling that far.
He also stressed that even though Proxima b is the closest exoplanet discovered, it’s still far, far away and would take thousands of years to reach with current technology.
He said it will probably be about 100 years before the technology exists to send people to the planet.
“Captain Kirk (of “Star Trek”) is about right,” Hollerman said. “That’s about the right era.”
Hollerman said NASA is researching if something could travel 1/10th the speed of light and land on the planet. Scientists are also researching how fast a person could travel and survive; if a person could go 1/10th the speed of light, it would take him or her only 40 years to reach Proxima b.
“Right now, what we know is very fragmentary,” said Dave Hostetter, planetarium curator at the Lafayette Science Museum.
He said scientists know only “fairly confidently” the planet exists, its minimum mass (about 1.3 times Earth’s mass) and how long it takes to revolve around its star (11.2 days).
Proxima b is very close to its star — closer than Mercury is to the sun — which makes it appear extremely dim, Hostetter said. In an exhibition at the planetarium, one can “fly” to Proxima b and see how the planet is so dim it almost appears as a black circle of negative space instead of an object. He said it is on the edge of brightness modern telescopes can detect; no one has imaged the planet, yet.
“Being able to image something like that will press our technology, I think,” Hostetter said.
He said new telescopes in the next 10 years might be able to see it better, but he doesn’t anticipate anything that could detect surface detail in his lifetime.
Hostetter added it could be possible in the future, with better telescopes, to study whether or not Proxima b has an atmosphere. The existence of atmosphere could give scientists a clue as to what the surface temperature is, he said.