New study suggests, Aliens on 1,000 nearby star system could see us.
There are about 1,000 star systems where aliens (if existed) could be watching us, suggests a new research.
We have 1,004 star systems in the direct line of sight to our planet. These planets are close enough to earth that aliens could not only detect Earth but also chemical trace life on Earth.
Over last decade, astronomers have found exoplanets orbiting distant stars using a simple formula. The formula is to keep an eye on the star and wait for it to suddenly dim. Dimming of the star means and signs of a planet passing in between the star and the telescope. As the star dims, there is a change of light which if analyzed can reveal the chemical content in the atmosphere of that planet. But this method only works for the planet whose orbits happens to take them in between their host stars and Earth.
Researcher flipped this method and asked: Which nearby stars are lined up properly for their inhabitants to see Earth transit in front of the sun? Would any life-forms in those star systems be able to detect signs of us, the living things on Earth’s surface? It turns out, the answer is yes. There are a great number of nearby stars.
Lisa Kaltenegger, a Cornell University astronomer and lead author of the paper said, “If observers were out there searching, they would be able to see signs of a biosphere in the atmosphere of our Pale Blue Dot”.
Researchers first confirmed finding one transiting in front of its star in 1992. Since then astronomers have found 4,292 confirmed planets beyond our Solar System orbiting 3,185 stars, mostly using the planet hunting Transiting Exoplanet Survey Satellite (TESS).
The James Webb Space Telescope (JWST), slated to launch at some point this decade, should have the precision to study many of those planets in more detail — possibly detecting gases like methane or Oxygen on their atmospheres, which would be likely signs of life.
What if aliens had their own telescope like JWST? The researchers found, there are 1,004 stars within 326 light-years that have vantage points to spot Earth. Out of 1,004 star systems, 508 have viewing angles that would give them at least 10 hours of observational data every time Earth passed between that location and the sun. These are the ideal conditions for spotting Earth and the signs of life in our atmosphere.
Lehigh University astrophysicist Joshua Pepper, co-author of the paper, said in the statement, “Only a very small fraction of exoplanets will just happen to be randomly aligned with our line of sight so we can see them transit. But all of the thousand stars we identified in our paper in the solar neighborhood could see our Earth transit the sun, calling their attention.”
Out of 1,004 stars about 5% are likely too young for life to have evolved, the researchers explained, even if a planet with habitable conditions orbited them. But the remaining 95% belong to star categories that can sustain life for billions of years. Earth’s evolution experience suggests that this is long enough for intelligent life to evolve, assuming conditions are right.
Two stars on the list have known exoplanets. And a red dwarf just 12 light-years from Earth with known exoplanets — known as Teegarden’s star — does not currently have the right viewing angle to spot Earth but at its current rate of movement will enter the Earth-spotting zone as soon as 2044.
Most of these stars are toward the farther end of the 326 light-year range, because the zone where Earth’s transit is visible gets smaller as you get closer to our solar system. But the closest star on the list is only 28 light-years away. And there are several more nearby stars that are on track to enter the zone where they might spot Earth within centuries. Some are bright enough in the sky to see from Earth.
The next step is to focus intelligent life-hunting operations on the 1,004 stars, , the researchers wrote, that are identified in their paper. They specifically mentioned SETI’s Breakthrough Listen program, designed to detect communications from advanced alien civilizations.