Suzanne Stewart
Staff Writer
For more than 60 years, astronomers, scientists and physicists have tried to answer the question – is their intelligent life outside of Earth?
At the Durbin Lions Club meeting last Tuesday, Green Bank Observatory Scientist Emeritus Jay Lockman presented a program on the Search for Extraterrestrial Intelligence – SETI – and the discoveries that have been made in the process.
Lockman, who previously worked for the NRAO in Charlottesville, Virginia, began his career at the Green Bank facility in 1993 with the intention of staying for just one year. Now, 31 years later, he reflects on all the work and accomplishments made during his time there.
“Lately, I’ve been talking about this particular topic because it really interests me,” he said. “That is the Scientific Search for Extraterrestrial Intelligence.”
In doing research through SETI, many questions are asked – is Earth special? Is there intelligent life on other planets? Did there used to be intelligent life on other planets? Where have they gone? Why don’t they communicate?
Those questions drove astrophysicist and astrobiologist Frank Drake to begin the search in 1960. He came to Green Bank and used the Tatel telescope to see if he could pick up radio signals from two nearby stars.
“No one had ever done that with enough sensitivity to have a chance of success,” Lockman said.
“Frank looked, saw nothing, and that got the ball rolling. A year later, at Green Bank, was the first conference on communications with extraterrestrials. There were about a dozen to fifteen people in the lounge there in the residence hall. They spent three or four days talking about the possibilities.
“Green Bank has been the center for SETI studies ever since.”
It was in that same lounge that Drake created the Drake equation which is used to estimate the number of intelligent civilizations in the cosmos. This equation is integral in the search.
So, the question has been asked over and over again – is there anyone out there?
“We know from life on Earth, you need a star to provide the energy,” Lockman said. “You need a planet to live on. You want the planet to be not too hot and not too cold. This is often called the Goldilocks criteria. You want it to have life and to have intelligent life.
“Finally, life that can communicate because it does us no good to have a water world filled with hyper intelligent dolphins,” he continued. “They’re not going to build radio transmitters. We won’t be able to communicate with them.”
Before 1990, humans were only aware of nine planets – now eight (sorry, Pluto) – in the solar system in the Milky Way. But is it possible there are other stars out there like our sun that could be orbited by planets?
There are.
“They started in 1990,” Lockman said. “There was a program – a series of telescopes dedicated to seeing if there were other planets around stars. Somebody likened this to trying to see the light of a firefly against a lighthouse beacon. It’s really tough. But it’s happened.”
Lockman shared an animated video from NASA that shows the progress of planet discoveries between 1990 and 2022. The planets are represented by circles that appear on the screen as they are discovered, and they are accompanied by a musical note.
The notes indicate the length of a year on the planets – high notes are short years; low notes are long years.
As the video starts, there is silence, then a blip and then another. Before long, as the counter raises, the musical notes hit a crescendo and create almost a symphony of sound. By the end of the clip, in 2022, 5,005 exoplanets were on the screen.
From that point, Lockman said it’s time to go back to that checklist to see if any of those planets could have supported life.
It’s easier to study planets that are nearby, so the focus was on Mars and Venus, the two planets closest to Earth. They both revolve around the sun and are within a distance that is “just right” according to the Goldilocks criteria.
So, is there or has there ever been life on Mars or Venus? At this point, that’s still an unanswered question.
It took a billion years or more after Earth was first formed for complex life to appear. That complex life went through many cycles to get us to where we are today.
“I was reading an article the other day about finding rocks that are two million years old that still have living bacteria in them,” Lockman said. “So, life is very stubborn, and it appears as soon as it can.”
Could Mars support life?
“Maybe at one time, but not now,” Lockman said.
“Here’s the thing, we now know Mars doesn’t really have an atmosphere,” he said. “The markings that people thought were canals were, in fact, just surface features seen through a blurry telescope. In fact, Mars is pretty inhospitable, and the reason it doesn’t have an atmosphere is interesting. It’s because it doesn’t have a magnetic field.”
The Earth has a magnetic field that protects the atmosphere from sun flares and other things the sun throws its way.
“When the sun’s wind hits the magnetic fields, you get aurora and we’re in the midst of solar activity,” Lockman said. “If we didn’t have a magnetic field, that wind would strip off the atmosphere, so that’s what happened to Mars.
“It may have had an atmosphere in the past,” he continued. “It may have developed life in the past of which there might still be remnants, but now it’s barren and lost its atmosphere because it didn’t have a magnetic field.”
What about Venus? It was less likely to support life than Mars.
“Venus is completely enshrouded in clouds and although it’s closer to the sun than the Earth. By the way, the clouds reflect sunlight – that’s why Venus is so bright,” he said. “So, the amount of sunlight that reaches the surface on Venus is the same that reaches the surface on Earth.
Past those clouds, though, the surface of Venus is even more inhospitable than Mars.
“We discovered only in the 1960s – a lot of this happened here in Green Bank – we discovered the surface of Venus is really hellish,” Lockman said. “It is so hot that you could melt lead on the surface. There are no oceans. It’s just incredibly hot.”
With those two planets pretty much eliminated, there’s still plenty of exoplanets out there that could possibly meet the criteria. The most important aspect of that is the intelligent life with the ability to communicate.
But because of the distance of these planets from Earth and the length of time it takes for signals to go from Point A to Point B, it’s a bit more complicated.
“It has to live long enough,” Lockman said. “If you have a civilization out there that gets to the point where it can communicate, but then a hundred years later stops, we’re not going to have contact.”
There are many reasons why a civilization loses its ability to communicate, the main being extinction. Much like the dinosaurs, all it takes is a meteor with the right trajectory to wipe out an entire species.
Lockman shared a photo of a meteor flying past Siberia 10 years ago. The meteor was the size of a school bus, and it merely grazes the Earth, still managing to injure a few thousand people.
“Had it come in straight down, a lot of people would have died,” he said. “I think about a million people would have died.”
In an effort to avoid meteor hits that could cause massive damage, NASA, under the direction of Congress, is cataloging all the rocks around Earth that could be a threat.
“We’ve even done experiments trying to move one out of the way,” Lockman said. “It doesn’t take much to move one of these rocks. All you’ve got to do is slow it up by a couple seconds and it moves past. So again, Green Bank, the GBT has been involved in some experiments with NASA trying to move them.
“Maybe a civilization has to get to the point where they can do a little space engineering in order to make it further,” he added.
The life span and health of the sun is also a factor. Planets rely heavily on the sun and sun flares or the sun losing power are things that can vastly affect a planet.
“If the sun did a major burp, we could be fried,” Lockman said. “But again, we’re not that far from being able to put up a shield. We may be a hundred years away. If we decide to, we can take control of some of these local threats.”
There are also internal threats that have to be considered. We as a species are very competitive and it has led to a lot of accomplishments, but it has also led to the demise of millions. War and climate change are two internal threats that could lead to the demise of the planet.
Going back to Venus, Lockman explained that he studied the planet when he was in graduate school to try to understand what happened to the planet and that was when he came across the phase “runaway greenhouse.”
“The atmosphere lets through light that heats the ground, but then the ground sends off infrared that’s trapped in the atmosphere by carbon dioxide,” he said. “That’s the blanket that keeps Earth warm. So, we have to study Venus and understand what happened there; understand the greenhouse on Venus and what went wrong.
“I’m still not sure we understand it, but we had to work through all of the math of that.”
Lockman’s instructor said to run the greenhouse equations on Earth next to see what it looked like. The class realized that humans were coming close to the point where we are heating up the planet.
Now we know that we have, and the planet is in fact heating up.
So, we return to the question – Is Earth special? Is it possible to find intelligent life on another planet?
There’s still some debate on the answers, but the fact remains, if we don’t search for answers, we’ll never have them.
“Frank Drake, who started this whole business, believed that if we could even find a signal from one other civilization out there, it would mean somebody got over their sustainability crisis,” Lockman said. “That it was possible to do it.”
The search has continued at Green Bank since Drake began it and, while a lot of interesting discoveries have been made, intelligent life isn’t one of them.
As part of Breakthrough Listen, which was founded 10 years ago, the GBT is still looking and is able to look because of the National Radio Quiet Zone, which lessens the amount of manmade interference to the data.
“We are so lucky as scientists to have the Quiet Zone,” Lockman said. “It’s unique world-wide. The data is totally public. You can go to their website and download what they’ve found.”
So, in the end, there is still only one planet with intelligent life and that is why, at the end of the day, Lockman said it is important we all work together to keep the Earth going because who knows? Someone out there may want to reach out to us, too.
“My personal moral for thinking about this stuff is, take care of the home place,” he said. “It may be the only place there is.”
To view the NASA video, visit https://science.nasa.gov/resource/5000-exoplanets-listen-to-the-sounds-of-discovery-360-video/