Learn the secret of Mars formation

About 4.6 billion years ago, Mars and the remaining planets in the solar system were formed. However, the precise understanding of how the planets in the solar system are formed remains a controversial topic. Recently, two hypotheses have been proposed to have the highest accuracy.

The most widely popular hypothesis is that the core deposition works well in the formation of terrestrial planets like Mars, but there are problems with giant planets. The second hypothesis is that the unstable disk method can explain the formation of giant planets.

Images of the solar nebula in our solar system, clouds of gas and dust formed by planets.(Image source: author William William Hart Hartmann, Institute of Planetary Sciences in Tucson).

Scientists continue their efforts to study planets within and outside the solar system to better understand these methods, in the most accurate way.

Core deposition model

The original hypothesis, known as core accretion , is that the solar system begins as a large, wavy cloud with cold air and dust, known as the solar nebula . The nebula is broken by its own gravity and flattened into a rotating disc. The matter is sucked into the center of the disk, forming the Sun.

Various small pieces of matter stuck together forming blocks called planetary objects (planetesimals). Some planetary objects combine to form asteroids, comets, moons and planets. The solar wind - charged particles emitted from the Sun - sweeps away lighter particles like hydrogen and helium, leaving behind all the small rock planets. However, in the outer solar system, the giant gas-producing planet is composed mainly of hydrogen and helium gas formed by the weakening of the solar wind.

Perhaps, extraterrestrial observations help determine core accretion as the formation process is affected. Stars contain many " metals " - the phrase astronomers use for other elements with more hydrogen and more helium - in their cores there are far more giant planets than those on planets. I am " poor in metal ". According to NASA, core accretion shows small, rocky worlds more popular than giant gas planets.

Discovered in 2005 about a giant gas planet with a giant core orbiting the sun - like the star HD 149026 is an example of exoplanet that enhances core accretion cases.

" This is a confirmation of the core accretion hypothesis for planet formation and the evidence that these planets should exist in richness, " Greg Henry said in a press release. Greg Henry - an astronomer at Tennessee State University, in Nashvilli - discovered faint stars .

In 2017, the European Space Agency plans to launch the CHARacterising ExOPlanet Satellite (Cheops), which will study different extraterrestrial planets in size from super-Earth to Neptune . Research on distant planets can help determine the formation of planets in the solar system.

" In the core accretion scenario, the core of a planet must reach its maximum mass before it can develop gas during travel. This volume depends on many physical factors, in the most important is the growth rate of planetary microscopic particles, "the Cheops team said.

By studying the material development of planets, CHEOPS gives insight into how " worlds " develop.

In the late 18th century, Immanuel Kant and Pierre Laplace first recognized the presence of core accretion. The core accretion hypothesis helps explain the formation of planets in the solar system. However, the discovery of " Super Earth " planets revolving around other stars is still a new hypothesis, proposed with the name " unstable disk ".

"Unstable disk" model

Although the core deposition model works well in Earth planets, the giant gas planet will need to grow rapidly to keep a significant amount of lighter gases that they contain. But these models cannot explain the rapid formation. Based on the models, this process takes several million years, longer than the light gases available during the early solar system. At the same time, the core deposition model faces changing problems, just like the planetary planet is capable of spiraling around the Sun in a short period of time.

According to a relatively new hypothesis, " unstable disk ", masses of dust and gas are bound together during the early formation of the solar system. Over time, these accumulated masses gradually merge into a giant planet. These planets can form faster than core deposition competitors, sometimes at least a thousand years, allowing them to keep light gases quickly disappearing. In addition, they also quickly gained a stable amount of orbit to keep them from " walking - dying " to the Sun.

If " unstable disk " affects the formation of planets, then astronomer Paul Wilson should produce a large number of worlds in a large order. Four giant planets orbiting a considerable distance around the star HD 9799 provide observable evidence for unstable flying saucers. Fomalhaut b , an extraterrestrial planet orbiting the sun for 2000 years, may also be an example of a world formed through unstable disks, although the planet may be ejected when interacting. with the planets around.

Compound Pebble

The biggest challenge to core accretion is time - build a massive gas planet quickly to capture the lighter components of the atmosphere. Recently, research on smaller objects, just the size of pebbles, fused together to form giant planets 1000 times faster than previously studied studies.

" This is the first model we know of when starting with the simple structures of the solar nebula, from what the planets formed and ended up being the giant planetary system we see. "Research author Harold Levison, an astronomer at the Southwest Research Institute (SwRI) in Colorado, told Space.com in 2015.

In 2012, researchers Michiel Lambrechts and Anders Johansen from Lund University in Sweden proposed that small pebbles, which were once removed, hold important elements to quickly build planets. giant.

" They showed that the remaining stones from this formation process, previously thought to be unimportant, could actually be a huge solution to planet formation ," Levison said.

The western image of the young volcano Olympus Mons has a gentle hill and slope with clear canals, some of which can also be created by liquid-water flow and some are clearly seen by rivers ice.(Image source: Nature / ESA / G. Neukum).

Levison and his team built on more accurate research models on how small stones form planets, observed in galaxies today. Meanwhile, simulation before, both large and medium-sized models, destroyed planets the size of pebbles by a relatively stable ratio. But Levison's simulation shows that larger samples act like " bullying ", " snatching " stones from mass-sized, medium-sized pebbles to grow at a faster rate. .

" Larger specimens now tend to disperse smaller samples than small samples that disperse them, so smaller samples end up dispersing out of the pebble disk ," co-authored. research author Katherine Kretke, also from SwRI, answered Space.com. "Basically, older boys often bully smaller boys so they can eat all the pebbles and continue to grow to form the core of giant planets."

"Heating" and "cooling"

Like all other planets, Mars heats up when formed by energy from collisions. Inside the planet melted and the iron-like particles sank to the center, forming the core. The lighter silicates (silicon anionic compounds) form the mantle crust, the " least dense " silicates that form the crust. Perhaps, Mars had a magnetic field several hundred million years ago, but when this Mars planet " cooled ", this magnetic field also " disappeared ".

The young Mars planet has active volcanoes , spraying lava onto the surface; Water and carbon dioxide enter the atmosphere. However, there is no tectonic activity on Mars, so volcanoes do not move and develop only when erupting.

" It seems that volcanic eruption can also help Mars have a thicker atmosphere. Mars's magnetic field protects the planet from radiation and solar wind. At a higher atmospheric pressure, water will But about 3.5 billion years ago, Mars began to cool, the volcanic eruption became less and less and the magnetic field disappeared as well. blown away and the surface of Mars was bombarded by radiation, "the study showed.

Under these conditions, liquid water cannot exist on the surface of Mars. Studies show that water is trapped underground in both liquid and freezing form; and in ice sheets on the polar ice cap.

As far as we know, life exists when water is in liquid form, so there is a lot of interesting evidence found on Mars.