Beijing time on November 28, the outer satellite refers to a satellite that circuits a certain planet outside the solar system, called an "exoplanet". Since 2009, the National Aeronautics and Space Administration (NASA) Kepler and Transit Excavator Satellite (TESS) mission have detected nearly 4,000 exoplanets, but astronomers only have an out-of-plane satellite. Described, and still not sure if it's a satellite.
The exoplanet Kepler-1625b and its possible satellites are estimated to be comparable in size to Neptune. The researchers said that this potential satellite and other similar alien satellites might have their own satellites.
In October 2018, David Kipping, an astronomer at Columbia University and his doctorate Alex Teachey, first reported in Science Advances magazine. A potential alien satellite.
Using NASA's Hubble Space Telescope, the two researchers analyzed observations when the exoplanet Kepler-1625b (Kepler-1625b) flew over a star. This is a planet similar to Jupiter, which blocks some of the light as it passes through the star. By analyzing the star-shaped light curve, the properties of the planet can be determined.
This method of observation is called the transit (occlusion) method. Astronomers have used this method to detect thousands of exoplanets. On the other hand, the researchers found two surprises while observing the Kepler-1625b process that flies over the star. First, the exoplanet flew over the star 1.25 hours earlier than expected, indicating that something produces gravity. Secondly, after the planet has completely passed the star, a very shallow gap occurs in the light curve, which may suggest a satellite behind the Kepler-1625b.
David Kiping said: "We have ruled out other possibilities as much as possible, such as detective errors, other planet's activities in the system or other star activities, but we can not find any other hypothesis that can explain our hands. All details about it."
This potential alien satellite is approximately equal to Neptune, about a third of Kepler-1625b. The size of a regular satellite is usually much smaller than the planet it circuits, so this volume is quite amazing. As for the current model for planetary satellite system formation, such a satellite should be very rare if it exists.
It is assumed that the quality of the Kepler-1625b is about several times that of Jupiter, and the quality of the potential satellite can only be 1.5% of it. This mass ratio is similar to the Earth and the Moon. In the earth and moon systems, the pattern is considered to be formed by debris of rocky planet collisions. However, astronomers believe that the Kepler 1625b and its possible satellites belong to a gaseous planet and do not consist of rocks, so this alien satellite can be formed by different processes.
"We can not hurry to open the champagne celebration now," said Alex Titcher. " But everything looks exciting, attractive and convincing. "
Are you looking for life on a satellite without satellite?
Some scientists argue that alien satellites can be a "very lively" world, meaning they are good places to live. This is because these satellites are not limited to using light energy from the parent stars in the system. Instead, they can extract energy from other places, such as:
Reflected light. Reflected light or thermal radiation from nearby planets can provide long term stable temperatures and can promote the development and reproduction of life.
Radioactive element. Radioactive substances such as uranium and thorium may exist deep in the rock formations of extraterrestrial satellites of similar earth size, and over time these elements slowly disappear and emit heat to the satellite head.
Tidal power. The gravity of a large exoplanet, such as Jupiter or Saturn's size, can mean alien satellites, creating tidal forces, similar to tidal changes produced by the earth's gravitational force. When the surface of the outer satellite consisting of rocks is drawn by the gravity of the exoplanet, the generated heat can reach the surface of the satellite.
There are about 175 satellites in the solar system we are in. Many of these satellites have these features, and two are also powerful candidates for finding extraterrestrial life: Jupiter's Satellite Europe (Meowe) and Saturn Satellite Accessories (Luke).
Both satellites have a frozen surface covered with striped stripes created by the planet's gravity forces at temperatures not exceeding 128 degrees Celsius. But just a few kilometers below the surface, there is a large floating sea that contains liquid water that exceeds the total amount of water in the soil. Where liquid water is present there may be life.
Where are the other satellites without bands?
Some astronomers estimate that there may be many such frozen satellites with underground oceans in Winter Street, which can be 100-1000 times larger than ground planets, but very difficult to find.
Kepler-1625b's parent star is about 8,000 light years from the earth, a distance that makes it a very small place on earth, but with advanced detection techniques, researchers can detect the weaknesses of the planet when it passes in front of them. . For the Kepler-1625b, this satellite is relatively easy to detect due to its large size. For other satellites that are not in the same plane as Europe, equivalent to a quarter of the earth's volume, it is not easy to detect the signal "gap" left by them as they cross the star. Under current technical conditions, these gaps are too small to be clearly identified. Therefore, we need a little more patience to find more alien satellites.