Earth like planets are those mainly composed of silicate stones.They followJupiter like planetThere is a big difference, because those gas planets are mainly composed ofhydrogen、heliumIt is composed of water, etc., without necessarily having a solid surface.Terrestrial planetarystructureRoughly the same: one is mainly the metal center of iron, and the outer layer is silicatemantleSurrounded by.Their surfaces generally havecanyon、Meteorite crater、mountainandvolcano。
On January 6, 2015, American astronomers issued a statement saying that in theory, it was determined that three to four of them were almost the same size as the Earth, and“Habitable zone”(Goldilocks Zone), which means there may be liquid water on it.
June 19, 2017NASA(NASA) announced the renewal of 219 candidate exoplanets, including 10 planets that are close to the size of Earth and operate in habitable orbits of their stars.
According to the data publicly provided by NASA's exoplanet archives, there are 4043 exoplanets, of which 2345 are confirmed by Kepler.Kepler has detected about 50 candidate planets in the near Earth size habitable zone, of which more than 30 have been confirmed.There are 389 confirmed planets discovered by K2.[1-2]
The structure of the earth is similar to other terrestrial planets[3]
The structures of Earth like planets are very similar: in the center is an iron based, mostly metal core, surrounded bysilicateThe main crust.MoonThe structure is similar, but the core lacks iron.Earth like planets have canyonsImpact crater, mountains andvolcano。The atmospheres of Earth like planets are regenerative atmospheres, which are different fromJupiter like planetDirectly fromSolar nebulaThe primary atmosphere.
Earth like planets includeMercury, EarthMars、Venus。Earth like planets are associated withearthSimilarplanet。Their distancesunlightNear, volume andqualityAll small, averagedensityLarge, surfacetemperatureIt is high, about the same size as the earth, and is also composed ofrockConstitutive.
Position of Earth like planets in Cygnus
Earth like planets or their rocks can be divided into two types, one is dominated by silicon compounds, the other is dominated by carbides, such as carbonaceous chondritesasteroid。These two types are called silicate planets andCarbon planet(or "Diamond Star"),
Earth like planets in the solar system
There are four Earth like planets in the solar system where the Earth is located: Mercury, Venus, Earth and Mars, and one Earth like planetdwarf planetCeres.And likePlutoAlthough there is a solid surface similar to that of Earth planets, ice is the main component (refIce dwarf）。When the solar systemformationThere should be many morecelestial bodies（Microplanet）But they may be merged or destroyedSolar nebulaForm fourgas giant In the process of.In Earth like planets,Hydrosphere。
As of May 15, 2022, scientific exploration has been carried out on the surface morphology, structure, material composition, magnetic field, etc. of Mars, and 940GB of original scientific data has been accumulated.[10]
The ball landed in the middle of the night and measured the temperature
one thousand nine hundred and seventy-five
Venus 9 and 10
Soviet Union
Send back the first photo of rock and soil
one thousand nine hundred and seventy-eight
Pioneer Venus
U.S.A
Draw the first global map of Venus
one thousand nine hundred and eighty-one
Venus 13
Soviet Union
Take a batch of color photos and analyze a soil sample
one thousand nine hundred and ninety
Magellan
U.S.A
Gravitational data collected
two thousand and five
Venus Express
Europe
Monitoring the cloud layer, atmospheric circulation and magnetic field of Venus
Earth like planets in the outer solar system
Found outside our solar systemsolar systemThe planets are almost allgas giant , the reason is very simple, because the gas giant is large, it is easy to observe or infer its existence.However, there are still a certain number of departmentsouter planetIt is suspected or confirmed to be an earth like planet.
Aleksander Wolszczan detected the firstOuter solar systemEarth like planets.There are three aroundPulsarThe mass of the planet PSR B1257+12 is 0.02, 4.3 and 3.9 times that of the Earth respectively.This was an unexpected discovery: their Ling was interruptedPulsarRadio wave radiation.(If it is not a track passing byPulsarIt is impossible to be found in front of.)
WhenPegasus 51bWhen the first exoplanet was discovered around a fusion star, many astronomers assumed that it was a huge earth like planet, because if it was a huge gas planet, it could not be close to the star at such a distance (0.052AU).However, a similar system followedouter planet(HD 209458 b) diameter is measured, and the phenomenon of Taranting shows that these planets are indeedgas giant 。
In June 2005, 15 light years awayRed dwarfThe first exoplanet that can almost be identified as an Earth like planet was found beside Gliese 876.The mass of this planet is 5 to 7 times that of the Earth, and the period of revolution of the star is only two Earth days.
On August 10, 2005, Probing Lensing Anomalies NETwork/Robotic Telescope Network (PLANET/RoboNet) andOptical gravity lens experiment(OGLE), inscorpioA star namedOGLE-2005-BLG-390LbThe mass of the cryogenic planet is 5.5 times that of the Earth.The newly discovered planet orbits its parent star at a distance equivalent to that of the solar systemAsteroid belt, the existence of this planet was revealed through the technology of gravitational microlens.This unique ability can discover land quality as low asEarth massThe planet of.
In April 2007, a team of 11 European scientists announced the discovery of a carbon planet in the habitable zoneExoplanet, has a temperature similar to that of the earth.This discovery usesEuropean Southern ObservatoryLocated in La Silla, ChiletelescopeThere is a special spectrometer, which can distinguish the oscillations of only a few wavelength amplitudes in the spectrum, which may reveal the existence of other worlds.They revealed the planets around the red dwarf Gliese 581, and the newly discovered planet was named Gliese 581c, which encouraged the research on the wobble of the same dim star, because 80% of planets similar to the Earth were found near the red dwarf.The newly discovered planet has a mass five times that of the Earth and is classified asSuper Earth。The discoverer is not sure whether it is a rocky planet like the earth or a frozen liquid on the surfaceWater planet。If it is a rock like the earth, according to the current mainstream theory, its diameter will be 1.5 times that of the earth. If it is an ice ball, its diameter will be larger.
In the future, a certain number of telescopes will be able to directly observe Earth like planets, including Territorial Planet Finder, space interferometry missionsDarwin, New World Mission, Kepler Mission and Owl (Overwhelmingly Large Telescope, OWL).Astronomers also believe that many or most of the sun like stars may have Earth like planets nearby.
Density trend
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The density of an Earth planet is the average mass at zero pressure.The higher the density, the higher the metal content.The density of Earth like planets will gradually decrease as the distance from stars increases.The following table listssolar systemEarth like planets inMoonAnd the six largestasteroid。
290 K; The first one is similar to the earthHabitable zoneOur planet may have liquid water.
Explore the track
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Late 15th century
fromSpainandPortugalThe geographical discovery initiated and completed has greatly expanded the world map.Immediately“Land power empire”With the decline and rise of the "colonial empire of sea power", the earth has since become a whole.
British scientists announced that a star 25 light-years away from the Earth“Vega”Vega may be surrounded by an earth like planet similar to the Earth.
seekExtrasolar planetsThe biggest difficulty is that the planet itself does not emit light, and the reflected signal is extremely weak. The light of the star must be 1 million 10 billion times brighter than that of the planets around it. The brightness of the star must be shielded to highlight the characteristics of the planet.NASAPrepare to solve this problem in many ways.
stayChileWorking at La Silla Astronomical ObservatorySwitzerlandAndFranceThe astronomy team discovered new earth like planets.The volume of this planetNeptuneEquivalent, the mass is about 17 times that of the earth, and its distance from the solar system is about 20.5Light year。
The planet is surrounded bylibraG1 581 ofRed dwarf(The mass of G1 581 red dwarf is about one-third of that of the sun).According to astronomers, it only takes five days for it to revolve around the red dwarf star.
EuropeWhen announcing the new discovery to the outside world, scientists from the Southern Astronomical Observatory said that they had not yet found a suitable name for the planet.
Astronomers say that most of the stars in our Milky Way are similar to G1 581 red dwarfs, and 80% of the stars near our solar system belong to this type.Astronomers are interested in studying such non gaseous giant planets.According to the French astronomer Javier Delverse, who was engaged in this research, "Our discovery shows that some smallfixed starThere are also ordinary planets around.This also gives us an enlightenment: red dwarfs can also become a key for us to explore other terrestrial planets.
Astronomers also said that only five of the more than 170 planets discovered were smaller than the newly discovered one.Astronomers used the HARPS system and theAstronomical telescope。
EuropeAstronomers also explained that the planet found this time was operating within the area of 6 million kilometers away from G1 581 red dwarf, and its surface temperature was about 150 ℃.As a comparison, Mercury, the closest planet in the solar system to the sun, is 58 million kilometers away from the sun. It takes 88 days to revolve around the sun.
January 2015
terrestrial planet[3]
Astronomers issued a statement on the 6th, saying that in theory, they determined that 3 to 4 more are almost the same size as the Earth, and“Habitable zone”(Goldilocks Zone), which means there may be liquid water on it.
These planets may not begas giant It is not covered by ice and snow, but a rocky planet like Earth.The latest results from the National Aeronautics and Space Administration (NASA) show that these stars get as much heat from their stars as we do from the sun.
But that doesn't mean they can become another earth.Their size and temperature may be similar to that of the Earth, but this is far from a comfortable environment.
According to the astronomer Guillermo Torres of the Harvard Smithsonian Center for Astrophysics, taking the two closest to the Earth as an example, if they have an atmosphere similar to the Earth, then the temperature of one planet should reach about 60 degrees Celsius, while the other should be kept at - 18 degrees Celsius.According to Torres, life may adapt to these temperatures through evolution.But they are 500 light years and 1100 light years away, and a light year is 9460.5 billion kilometers, which is too far away for the earth.
However, Douglas Caldwell, an astronomer at SETI, believes that the key to this discovery is that astronomers are one step closer to discovering the Earth's twin planet.Torres also said: "These planets do exist. We didn't know it before. What we are looking for is signs of life. We have not yet reached that step, which will take many years, but now we have taken the first step."
Torres' team confirmed that, so far, a total of 8 to 9 planets with the size similar to that of the Earth and in the habitable temperature zone have been found.But this is only the discovery of a small part of the Milky Way in a close search, so Torres believes that there are still more Earth like planets in the whole universe waiting for us to discover one by one.[4]
August 2016
On August 15, 2016, foreign media reported that astronomy was making major discoveries!Scientists may announce the discovery of a planet "similar to the Earth" in the Milky Way at the end of August.It is said that this planet has the possibility of breeding life, and this "Earth" is much closer than the "close relatives of the Earth" found last time.It is reported that there may be liquid water on the surface of the new planet, which is an important condition for breeding life.NASA has repeatedly announced the discovery of new planets.However, most of the newly discovered planets are too hot or too cold to hold liquid water on their surfaces. Some are gaseous planets like Jupiter and Neptune, different from the rocky Earth or Mars.[5]
February 2017
At 2:00 a.m. Beijing time on February 23, 2017, NASA held a press conference at its headquarters, announcing that as many as seven exoplanets with a size close to the Earth had been found around a short-range low mass star, and that these planets were very close to each other, basically located in the habitable zone around the star, so theoretically there might be atmosphere and oceans,Thus, people are full of reverie about the possibility of life.This discovery shows that small rocks squeezed together like Russian bowlsPlanetary systemIt may be quite common, and perhaps it will become the best destination to search for extraterrestrial life in the Milky Way.[6]
Human imagination
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Charles Beckman, a TPF project scientist, said on April 28, 2004,U.S.ANASA is expected to launch a small sundial in 2014 to highlight planets by blocking the brightness of stars.By 2019, the United States willEuropean Space AgencyCooperation, launchFree flightInterferometer.This will be a pair of celestial telescopes that strictly abide by the distance between them and a football field, using zero signalInterferometryThe signals of the two celestial telescopes are integrated, and the signal peak is superimposed with the signal trough to remove the bright stars from the image. The light reflected by the planets rotating around the stars can pass through the telescope in different pathsoptical system , leaving traces on the image.
Space telescope for finding earth like planets[3]
According to the observation, three stars near the solar system, Beta PictorisTianyuan IV(Epsilon Eridani) and Vega may have another solar system with earth like planets.
Free flyingInterferometerSpitzer to be launchedSpace telescopeandJames·weberSpace telescope, andKeplerPlannedPlanetary explorationThe space telescope will be able to scan thousands of distant stars and find planets only several times larger than the Earth around several stars in the nearby solar system.But that's not enough.
All these instruments are preparations for the Earth like Planet Searcher (TPF). The TPF-C and TPF-I planed to be launched in 2014 and 2018 will be combined tohubble space telescope The resolution achieved is increased by 100 times. Through joint observation in the infrared and visible light wavelength range, it will be possible to discover and detect Earth like planetsPlanetary atmosphereThe ability of chemical components in.If TPF can find signs of life in Earth like planets,American AirlinesNASA will apply for more powerful telescopes after 2020 to identify and photograph the life characteristics of planets.
Is there a little green man
In that faraway placeWhat can we find?University of ColoradoBiologyBruce Yakeski, the chief scientist of the research office, told the Oriental Weekly that he wanted to find an Earth like planet that could support life on Earth,Liquid waterOr other forms of liquid are basic conditions, such ascarbon、hydrogen、oxygen、nitrogen、sulfur、phosphorus、calcium、ironAnd other materials are easy to find on any planet with geological activity.Another necessary condition is chemical imbalance. The existence of this imbalance and the efforts to constantly restore balance provide the energy necessary for metabolism.
Some scientists say that life on the earth is based on carbon, while carbon is the same specieselementSilicon based life forms are also possible.Seth Shaw, senior scientist of "Phoenix Project"Stark It is believed that, from the perspective of the outer electronic structure of silicon, it does have four free electrons unique to carbon, but silicon has a large atomic weight, and the silicon oxygen covalent bond is relatively weak, so it can not combine organic macromolecules like carbon, so it can not be used as the basis of life.He said that life is composed of organization, function and accurate replication. Its core is the transmission of information. It cannot be ruled out that it may form other forms of chemical mechanisms according to the behavior of electrons.
thatalienWill it be like in the movie, with green skin and surviving by photosynthesis? Seth said that, using skin photosynthesis, aliens can only use 8% of their energy. Even if they are exposed to the sun every day, they cannot meet their own energy needs. It takes three weeks to store the energy needed for a day.Therefore, aliens cannot survive by photosynthesis. It is more direct and effective to obtain energy by eating green plants.
Ultimate breakthrough
An international research group, including scientists from 12 countries including France, published thebritainNaturemagazineThe report said that they used a technology called gravitational microlens to detect a new earth like planet, which is the smallest earth like planet found by humans outside the solar system so far.
When a planet or star moves in front of another distant star, the object in front sometimes looks like“lens”Similarly, the distant objects behind will be magnified to make them more bright in the eyes of observers, which is called“Gravitational lens”Effect.Scientists have recently used this phenomenon to develop a new technology for detecting unknown planets - gravitational microlens technology.
Searching for planets similar to Earth is explorationextraterrestrial life The important topic of.Previously, scientists had discovered more than 170 Earth like planets by using traditional planet detection technology. However, due to technical limitations, the Earth like planets discovered at that time were often larger, and the smallest planet was about 7 times the mass of the Earth.By FranceAstrophysicsThe international research team led by the scientists of the Institute has discovered a smaller planet using gravitational microlens technology.This planet, named OGLE-2005-BLG-390Lb, is 28000 light years away from the Earth, and its mass is about 5.5 times that of the Earth.
Scientists said that the newly discovered planet orbits a brown dwarf star, and the distance between the two is about 2.6 times the distance between the sun and the earth.However, due to theRadiant energyVery low, so the temperature of the planet's surface is only about - 220 ℃, which is absolutely not suitable for life.
Scientists hope that in the futuregravitationMicrolens technology, detectingmoreEarth like planets with less mass.
——The water temperature may be suitable for human habitation
The observation team composed of 11 European astronomers found a planet that may be suitable for human habitation outside the solar system for the first time.This planet has a temperature similar to that of Earth.Scientists described the discovery as a big step in "searching for life in the universe".
Standard of residence
ChileanEuropean Southern ObservatoryThe planet was discovered.This planet is the right size, and may have liquid water.In terms of the concept of the Milky Way, it is relatively close to the Earth, 12 trillion miles away.However, the star around the planet is a "red dwarf", which is much smaller, darker and colder than the sun.
This newly discovered planet still has many unknown places. However, this is the first time that a planet outside the solar system meets the requirements of astronomers for a planet suitable for human habitation: the size is relatively similar to the Earth, and the temperature is allowedLiquid waterThe exists of.
The results of this discovery have not yet been published, but have been submitted to the journal Astronomy and Astrophysics.
Open the door to more discoveries
The observatory's scientists observed that the planet orbits a red dwarf star Gliese 581.Red dwarfs are low energy, smaller stars.Red dwarfs emit dim red light, which lasts longer than the sun.
The newly discovered planet is named "581c".This discovery will certainly lead to the study of planets surrounding similar faint stars.About 80% of the stars near the Earth are red dwarfs.
"581c" weighs about five times more than the earth.The scientists who discovered "581c" are not sure whether it is a rocky planet like Earth or a "big ice ball" with liquid water on its surface.If it is composed of rocks like the earth, its diameter is about 1.5 times larger than the earth.If it is a "big ice ball", the diameter may be larger.
According to theory, "581c" should have an atmosphere.But the composition of the atmosphere is still a mystery.If the atmosphere is too thick, the surface temperature of the planet will be too high.
Whether liquid water exists
However, scientists believe that the average temperature of "581c" is between 32 and 104 ℃.The discovery caused astronomers to celebrate.
All 220 discovered by astronomersExtrasolar planetsIt's either too hot, too cold, or too big to live in.The newly discovered "581c" looks just right.
NASA'sAstrobiologyChris McKay, an expert, said: "This may be very important. It does not mean that there is life there, but it means that it is a planet similar to the Earth according to its possible habitability."
Another astronomer hypothesized that, in addition to having a suitable temperature, the newly discovered planet might also be full of liquid water.But that is not based on any evidence, but on the theory of planetary formation.
Other astronomers cautioned that it was too early to say whether there was water on the 581c.
Days of the year
The galaxy where the new planet is located is only 20.5 light-years away from the Earth, and the star Gliese 581 in the galaxy is also one of the 100 stars closest to the Earth.
For everyone who wants to go to "581c" planet, they must know that it will be heavier to sit on that planet;And their age will also increase faster, because it takes only 13 days for "581c" to circle the star.
On "581c"Gravitational accelerationIt is 1.6 times of that on the earth, so you will feel that your weight has increased 0.6 times.
"581c" is 14 times closer to the star than the earth is to the sun.From the view of "581c", the size of stars in the sky is larger than that seen on the earthmoon20 times larger.Moreover, "581c" probably won't rotate, so half of it will always be day and the other half will always be night
Research findings
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Life evidence
Scientists discover new evidence for life on Earth like planets
The plants on Earth like planets may be red
The discussion about whether there are earth like planets outside the solar system, and even whether there is life on these planets has continued.along withuniverseContinuous progress of detection technology, daysLitterateurMore and more earth like planets have been discovered, and scientists have been paying more attention to the research in this field.A few days ago, fromNASAIn a study, 30% of astronomers found new evidence through spectral analysis to confirm that Earth like planets do exist, and there is likely to be life on these planets.
In the next ten years, when the writers can study the earth like planets outside the solar system, they may find that the plants growing on those planets are not green, but may be yellow, orange or red.On other planets, other spectral colors may take advantage, and plants may absorb more green or blue light and reflect off light they don't need.[9]
This conclusion is made byNASASponsoredCaliforniaScientists from the Virtual Planet Laboratory of the State Academy of Sciences.Scientists use computer models to simulate the future search and study of Earth like planets.The scientists published the latest research results in the journal Astrobiology. The article also discussed how the plants on Earth like planets conduct photosynthesis.
Nancy Creon, a biologist from NASA's Goddard Space Research Center, who is in charge of this research, said that it is very important to determine the possible color range of plants on earth like planets outside the solar system, because scientists need to know what to look for when they get spectral information from these planets.
Kryon said, "Plants may present yellow, orange or red images through photosynthesis. I don't think blue is possible. Of course, green is the most likely to appear, as is the case with plants on the earth."
From California Institute of TechnologyAstrobiologistThe director of the Virtual Planetary Laboratory, Victory Maidels, said, "We have adopted interdisciplinary technologies in the research process. The entire research activities include many disciplines, including planetary science, biology and meteorology. These interdisciplinary technologies make our research activities more significant.At the same time, this research activity also provides a lot of reliable basis for us to detect the spectrum of Earth like planets outside the solar system.Because in some special periods during the growth of the planet, it will reveal a lot of information through the light emitted to the outside world, such as whether there is water or life on the planet, which is necessary for us to explore Earth like planets. "
Middles was the first scientist to combine biology with planetology. She said that such a model could not be constructed through planetology, biology or meteorology alone, and interdisciplinary cooperation was needed to make a breakthrough in this area.
In this project, scientists focused their research on the principle that plants use the energy of light to produce sugar, which is what we usually call photosynthesis of plants on the earth, because the pigments formed by photosynthesis must be consistent with the spectrum of these light.The light shining on a planet is not only related to the source of light, but also closely related to the atmosphere around the planet.For example, the ozone layer above the earth can attract ultraviolet rays from the sun.
Kryon explained, "This confirms that the number of photons in the spectrum is very important for us to find Earth like planets. Most of the particles in the solar rays that hit the earth are red, which is why the plants on the earth are green.On the earth, plants attract blue light and red light. The energy contained in these two lights can meet the growth needs of plants, so there is no need to attract other light.Therefore, the color of the plant is green. "
Earth like planets outside the solar system may also revolve around planets similar to the sun, and their surrounding atmosphere may be similar to that of the earth, so this planet may appearBotanyThese plants can also absorb the energy of red light, blue light and green light, but the color of these plants may not be reflected as green.Because of the light it absorbs, red light is not necessarily the most. If other light accounts for the majority, then plants will show other colors, such as yellow or red.
terrestrial planet
There may be other factors that affect the color of plants, such as the ozone layercarbon dioxideAnd water vapor and starsradialChemical reaction with planetary atmosphere, etc.Maidels said, "We have taken these factors into account when building the model of the Earth like planet, and we also found that there is a layer of substances similar to the ozone layer over the Earth like planet that can effectively resist strong ultraviolet rays and protect life on the planet.Earth like planets should have water several feet to tens of feet underground. The temperature of stars in their planetary galaxies should be lower than that of the sun, but they can still meet the needs of photosynthesis.In a word, the model we have built is a powerful weapon to find Earth like planets and even life on them. "
astronomerWe used to think that there were few earth like planets outside the solar system, but with the continuous development of space exploration technology and newSpace telescopeThey have found more and more planets with the same size as Jupiter.So it is reasonable to believe that there are many earth like planets in the universe.
Kepler-22b vs. solar system[2]
Maidels said, "We may not find a planet like the Earth, but there may be widespread bacterial life on these terrestrial planets. If we can find an environment suitable for the formation of life on a terrestrial planet, then we should think that there may be life on this planet."
The Virtual Planet Lab isNASAA branch of the Institute of Astrobiology, established in 1997, whose purpose is to promote, manage and guide interdisciplinary astrobiology research, while training a new generation of astrobiologyresearcher[7]
This is the code named“Kepler-22b”The planet ofStellar systemA hypothetical comparison with the solar system.NASA announced on December 5 that scientists used KeplerSpace telescopeAt a place about 600 light-years away from the earthStellar systemA newHabitable planetIt is also the smallest and most suitable planet for liquid water on the surface.This planet, code named "Kepler-22b", has a radius about 2.4 times the radius of the Earth, and is located in the stellar system“Livable zone”The main composition is not clear, and the period around the star is about 290 Earth days.
Discover planets
Kepler 186f planet
According to foreign reports, the International Astronomical Organization said on the 18th that a newly discovered planet seems to be just suitable for the conditions of life as we know it.Not too big and not too small, not too cold and not too hot.This one is calledKepler-186fIt is 500 light-years away from the earth, about the same size as the earth.As astronomers explain, it orbits its star at a distance just enough to make liquid water on the surface of the planet.We know that this is the basic condition for the existence of life.[3]
howeverNASAPlanetary scientist Quintana said via internet phone that it is not exactly the same as the Earth.NASA planetary scientist Quintana said: "It is more like a cousin of the Earth than a twin. It has the same characteristics with the Earth, but their parent star is very different."[3]
Kepler-186fThe surrounding star is smaller than the sun and its temperature is lower than the sun.However, astronomers wrote in the scientific journal that this planet is more similar to the Earth than most of the hundreds of planets previously discovered.[3]
research findings
terrestrial planet[4]
The scientists of the research group believe that it is likely thatnickel/ironTopographic structure of rock or silicon cover.Between the earth's land structure andUranus/Neptune's heated giant ice structure between.It has dense vapor clouds.This achievement was made byHawaiiMauna KeaApicalKeck Observatory Observed.Keck Observatory has two of the world's largest 10 meter optical giant telescopes.Each one is eight stories high and weighs more than 350 tons.The success of this discovery is also due to the improvement of Keck Observatory technology - spectrometerCCD detectorThe accuracy of theGalaxyPlanets with internal mass equal to that of the Earth have laid the foundation.
scienceMy family found a planet very similar to the Earth outside the solar system.Its planet number is 155, which is the smallest planet outside the solar system.Its radius is twice that of the earth and its mass is 7.5 times that of the earth.3 million kilometers (0.021Astronomical unit）。Of this planettrackThe period is 1.94 days.Its orbit size is onlysolar systemMercuryOne tenth of the track.This oneNew findingsOf the planetGalaxyIt is called Gliese 876.It orbits a star called Gliese 876.
On March 30, 2015, the report entitled "Earth like planet Tatooine in the<Star Wars>may be ubiquitous" was published. It said that a gas giant planet that is not suitable for human habitation has been found orbiting a binary star. Many researchers believe that it is impossible to form a rocky planet there.Mathematical simulations show that solid earth like planets like Tatooine are likely to exist and may be widespread.
"Tatooine sunsets may after all be very common," said astrophysicist Ben Bromley of the University of Utah and Scott Kenyon of the Smithsonian Institute Astrophysical Observatory[8]
