It was analyzed that there are 2,034 stars that can determine the existence of the Earth by observing the Earth’s covering of the Sun from 5000 years ago to 5000 years later. Provide open science
An analysis result has revealed that there are 2,034 stars within the observable distance of human civilization. However, if there is an Earth-like planet orbiting around these stars, it is attracting attention from academia because it raises a new perspective that extraterrestrial life observing the evolution of Earth’s civilization may exist.
Lisa Caltenegger, a professor of astronomy at Cornell University in the US, said that 1,715 stars have been able to discover the Earth from 5000 years ago to the present, and 319 stars are in the position to find the Earth in the next 5000 years. It was announced on the 23rd in Nature.
Astronomers use starlight to find planets orbiting stars like the Sun. When a planet orbits a star and covers the star, the starlight instantly dims. This phenomenon is the principle of understanding the existence of a planet. This method is only possible at a distance close enough to observe the planets obscuring the stars. Scientists believe that only within 326 light-years (the distance that light travels in one year) can a star lose its light because it is obscured by a planet.
The research team found a star exhibiting this phenomenon in the list of stars in the Milky Way, ‘EDR3’, published in December last year by the European Space Agency’s (ESA) galaxy observation satellite ‘Gaia’. It is estimated that there are 1.8 billion stars registered in EDR3, of which 333,312 are within 326 light years of Earth. The research team again selected 2,034 stars within 326 light-years from 5,000 years ago to 5,000 years later. The research team used the reference period from 5000 years ago to 5000 years ago to count the number of stars with planets that could observe changes in human civilization if extraterrestrial civilizations exist.
The research team confirmed the fact that there are 75 stars within 100 light-years of a location that will receive radio waves sent by humans into space. Radio waves, which started in the United States in 1920, travel at the speed of light and are estimated to have reached as far as 100 light-years.
Los 128, 11 light years away from Earth, has been analyzed as the closest star with a terrestrial planet with a high possibility of an extraterrestrial civilization. A planet 1.8 times larger than Earth revolves around this star. However, it is analyzed that if life with a high civilization lived from 1036 BC to 1121 AD, they could have watched the Earth pass through the sun.
On Earth, you can see Trappist-1, a planetary system with 7 terrestrial planets worthy of life, but Trappist-1 is unaware of the existence of the Earth. When viewed from Trappist-1, the Earth, 46 light-years away, must pass in front of the Sun to know the existence of the Earth through starlight, because it is not currently visible from that angle. However, from 3663 to 6034, 1642 years from now, you can see the Earth passing in front of the sun from Trappist-1.
So far, astronomical research has been conducted from the perspective of looking at the universe from the Earth. However, this study is new in that it deviated from this perspective and presented a perspective shift in which the existence of a distant universe can search for the existence of the earth in the same way. Astronomers hope the study will help prioritize the search for extraterrestrial life. Professor Kaltenegger said, “These stars are like sitting in the front seats of a huge theater called the universe and watching mankind. Anything you can imagine is possible,” he said.