Scientists have good reason to believe that the so-called water-worlds extrasolar planet with a surface completely covered in one giant ocean common in the galaxy. But a new computer & # 39; computer simulation shows that not only water worlds are common, they also have a lot of water, and a staggering scale. Imagine the oceans are hundreds and even thousands of kilometers in depth.
A new study published today in the Proceedings of the National Academy of Sciences strengthens the growing body of that water worlds with & # 39 are a common feature of the Milky Way. Using computer simulations, a Harvard University astronomer Li Zeng and his colleagues presented the new data, which show that the sub-Neptune-sized planets, ie planets that show the radii of the two to four times larger than the Earth, which may be water worlds, and no gas dwarfs surrounded by lush atmospheres, usually considered ,.
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To be clear, water worlds, also known as the worlds ocean, still hypothetical. Unless, of course, we do not include the moon Europe of Jupiter and Saturn's moon Enceladus, both of which are believed to be the global oceans, wrapped in ice. Planetary formation models suggest water worlds are real, however, and probably very often. Research carried out in 2017, for example, offered the most populated of the Earth as a planet can actually be water worlds.
For the new study, Li's team sought to improve our models of planetary formation even more. Observations made by Kepler and other observatories allowed astronomers to identify the thousands of exoplanets, many of which are located in close proximity to their host stars (relatives, we are talking away, even closer than Mercury to the & # 39 is our sun). These data indicate two dominant types ekzoplanet in the range of from one to four times the Earth: dense stony worlds (so-called super-Earths) or intermediate sizes planets with relatively low density. It is this last category of interest in the new study, because scientists are not sure that these extrasolar planets have a rocky core surrounded by a dense hydrogen-rich atmosphere (ie dwarf gas), or if they contain significant amounts of water or ice or liquid, or a combination of the two (i.e., water worlds).
Traditional thinking suggests that they dwarf gas, since water worlds can be formed only for the "snow line" planetary system (distance from the host star where it is cold enough for the volatile compounds to form solid ice grains). New computer models, however, suggested that the sub-The Neptunes should appear very modest atmospheres in terms of size, certainly nothing on the scale of gas dwarf. At the same time, the simulation of planetary growth and development showed many intermediate-sized planets as water worlds.
This conclusion arises after the strengthening of the other theory that planet migration. Since water worlds can be formed only in the outer reaches of the star system, and because many sub-Neptunes exist in close proximity to their masters stars, this study provides a theoretical proof that the planet, including water worlds, slowly drifting inside for a long time .
"Incomprehensible. Bottomless. Very deep ".
Sub-oceanic water worlds, as new research has shown are likely to be very wet. At least 25 percent of the total weight of the planets will consist of water with a predominance of ice and liquids. Some of these planets may even consist of 50 percent water. These aqueous worlds, thus not only without the planet earth-surface features are mostly waterlogged balls with bits of rock and metal, for good measure added. For comparison, the Earth essentially rocky with a water content of about 0.025 percent of the total weight, and having a water content in an atmosphere containing only one millionth of its total weight.
Sub-Neptune water worlds "are not only underwater," explained Lee email Gizmodo, they have the ocean depths greater than "hundreds or thousands of kilometers of" deep "rather than several kilometers depth as Earth's oceans." To which he added a few apt descriptors: "Incomprehensible bottomless very deep"…
Or at least that is what was offered computer & # 39; a computer simulation. The models used in the study of the formation of the simulated world, as influenced by the richness of the nebula gas rich in ice water, different stony material consisting mainly of iron and nickel, as well as by a complex chemical process is caused by temperature, cooling rate, evaporation , condensation, density and distance from the host star, among many other factors.
Looking at the simulation, Lee was amazed at the amount of water that seems to be in the galaxy and its prominence on the stage of planet formation.
"Statistically speaking, these water worlds may be more abundant than the Earth, as the rocky planets," said Lee Gizmodo. "Perhaps, each typical of the sun, the star has one or more of these water worlds [and maybe] our solar system with a & # 39 is less typical. Generally speaking, this type of planetary system architecture with close to a rocky super-Earths and water-rich sub-The Neptunes may be more common in the Milky Way than our type of solar system, "he said.
Some of these planets, he said, there are oceans deep enough to exert a pressure equivalent to a million times on the surface of our atmospheric pressure. Under these conditions, liquid water is compressed to high pressure phases of ice, such as Seven superionic ice or ice, he said.
"These high-pressure ice, in fact, as the silicate rocks within the deep mantle, they are hot and the solid Earth," he said. "This is a completely different worlds compared to our Earth."
Our planet has a clear surface, but the sub-oceanic water worlds, not so much. Aqueous formulations range from 25 to 50 percent of the total mass of the planet of the & # 39; objects would be completely swamped. They "may or may not have a well-defined surface," said Lee, and they "may be liquid all the way down all the way down to a great depth."
Sean Raymond, an astronomer at the University of Bordeaux, who was not involved with the new study, reported sound newspaper.
"His conclusions are the statistical, which means that the authors do not point to specific planets and claiming that they are water worlds, and focus on the general population," Raymond told Gizmodo in an email. "Nevertheless, it's cool and provocative paper result."
Raymond especially stoked how the study added further confidence in the hypothesis of planetary migration.
"Water World is close to its star to be formed much farther, then moves closer as its orbit is tightened. The composition of the planet was set when he was on a cold orbit, "he said. "The process of orbital shrinking called" migration "and is driven by gravity gas disk from which the planets. When water worlds with & # 39 are common, which provides very strong evidence that migration does occur, and with the & # 39 is a key process in how planets form, and around other stars in our own solar system. "
Raymond also found it interesting that a water content of 25 percent is about the same as for the exterior of the & # 39 Solar System objects like Pluto and comets 67P. It "fits into the history of the migration of these water worlds, perhaps, originally born far from its star before going on inside," he said.
"I like modeling like this," wrote Anders Sandberg, senior researcher of the future Humanity Institute at Oxford University, also not involved in the new study, in an email to Gizmodo. "Really cool thing is that this article is in some sense a bet that we will discover in the next few years: the actual data collected in a different speed, which will allow us to check with the & # 39 is the prediction is true."
Indeed, the good aspect of this work with the & # 39 is that the data is telling us that we should be looking for as soon as we get access to the next generation of space telescopes, including the James Webb Telescope and ESA's Space Telescope Ariel. Sandberg also said that the new discovery is important in the search for extraterrestrial life.
"While water worlds is not quite ideal for life as heavier elements may be buried under hundreds of kilometers of high-pressure ice, they are probably much better than gas dwarfs," he said.
How can or not watery planet facilitate intelligent, space types, it is another matter entirely, and, of course, the question is worth considering, given the seeming abundance of planets in the galaxy.