Where to search for aliens

Scientists believe that only planets of the same size as the Earth, within the Goldilocks region and satisfying a host of other factors, meet the conditions for life development.

According to the BBC, the recent European astronomers have confirmed the discovery of "Earth's copy" around Proxima Centauri , only 4 light-years away from the Sun, heating up the topic of finding life outside. universe in the scientific world.

"When talking about a planet" with potential for life "means the measurable indicators of the planet needed for life development," said Professor Abel Méndez, University of Puerto Rico (UPR) for know.

The two most common criteria in discussions are that the planet size must be within the Earth's size in general (so that it can be made of stone), and secondly, it must be within the Goldilocks region - the preferred area. for life to grow near a star.

The Goldilocks region is the distance to the parent star so that the planet can hold liquid water on its surface. If it is too close, the water will evaporate too far and the water will freeze.

In addition to these two criteria, there are a number of other factors that affect a planet's ability to match the life of a planet. Several planets have been excluded from debates due to limitations in today's technology.

The more cold the star is, the smaller the area where life is.(Photo: NASA).

"When researching about what makes Earth viable, magnetism is an extremely important factor," said Professor Don Pollacco, a planetary researcher at the University of Warwick, England.

"We can't measure the magnetic fields of other planets, so we have to put it to a b."

Most planets with potential for extraterrestrial life revolve around a red dwarf, smaller, colder and darker stars than the Sun. This is the popular star type of the Milky Way - about 75%. Scientists often focus on these stars because it is easier to find small mass planets around these stars.

Astronomers often search for a new planet in two ways: through the radial velocity, caused by the gravitational force between the planet and the parent star, or through the star's light reduction whenever the planet passes through. before light.

The first is suitable for small planets orbiting a star of a similar size rather than a star much larger than it. In the second way, a stone-made planet would block much of a red dwarf's light, while the shield from a Earth-sized planet through a bright star like the Sun is often overwhelmed by the dazzling.

Because red dwarfs have a lower temperature than the Sun, planets need to be closer than the Earth - Sun distance to get enough heat to keep liquid in liquid form.

This is also advantageous for astronomers, as it is nearer so the time to spin around a parent star is shorter than Earth, allowing them to observe more.

However, the closer the planet is to the star, the more likely it is to lock the tide (like the Moon to the Earth). If the tide is locked, the planet will always point to the star on one side, meaning half is always day while the other half is always in the dark and cold.

"The only way to transfer heat to the dark half is through the planet itself or the atmosphere (if any). Some people believe that if half-hot and half-cold, somewhere in the middle will have a temperate temperature" , Don Pollacco explained.

Another problem of small stars is that unpredictable and unstable phenomena often occur. Professor Pollacco and colleagues from Warwick, Belfast Queen's University and Aarhus University of Denmark have discovered the star Kepler-438 , one of the potential life systems discovered by Kepler's telescope. NASA, can launch many cosmic particles into space. These massive charged particle launches can blow away the atmosphere and grill all life forms that exist on the surface of nearby planets.

Search for planets through stars' brightness reduction.(Photo: NASA).

According to Don Pollacco, it is possible that the life forms of these planets develop differently than Earth, so it may be wrong to go on searching for life forms similar to Earth. Dr. Jon Jenkins, a co-researcher on Kepler's mission, concurs with this view.

"To search for life, we need to turn each stone up to see if there's anything below it , " he said.

The newly discovered planet orbiting a red dwarf Proxima Centauri can be used to verify various theories, according to Professor Abel Méndez, head of the alien life laboratory at UPR.

"If these stars are not suitable for life, it means that 75% of stars in the Milky Way are the same," he said.

Not all potential planets orbiting dim stars, small masses. Kepler -452b was discovered by NASA in 2015 larger than the Earth, orbiting a 385-day solar-like star, believed to be the Earth-like planet to date, although these planets are very difficult. detect.

The next step of the search for alien life with the new generation of devices is to look for signs of biogas, like oxygen or methane in other planets' atmosphere, though not enough to be considered a discover.