Is there an earth like the earth in our world?

Generally speaking, what we call "the world" refers to the earth. You mean our universe, right?

A planet like the earth.

If there really was a planet like Earth before, let alone other alien galaxies. It's too far. There is no theoretical support, which is ridiculous. Suppose it's in the solar system. In fact, Mars is most likely to be closest to us. For example, if we start to transform Mars now, your grandson's grandson can immigrate to Mars to live. At that time, Mars will be blue. Rivers and vegetation are everywhere.

In 2000, the United States discovered a Martian meteorite in Antarctica, numbered ALH8400 1. NASA claims to have found some similar micro-fossil structures on this meteorite. Some people think that this may be evidence of life on Mars, but others think that this is only a naturally occurring mineral crystal. But until 2004, neither side had the upper hand.

There is evidence that Mars was once more suitable for the existence of life than it is now, but whether there is life on Mars can not give a definite conclusion. Some researchers believe that ALH8400 1 meteorite from Mars has evidence of past life activities, but this view has not been recognized. Another objection is that because meteorites were born billions of years ago, they have never been at the temperature where liquid water exists for a long time (so there will be no life activities).

The Viking probe has done some experiments to detect microorganisms that may exist in Martian soil. The experiment was limited to the landing site of the Pirate and gave a positive result, but it was later denied by many scientists. This is an ongoing debate. Existing biological activities are also one of the explanations for the existence of trace methane in the Martian atmosphere, but people usually agree with other explanations that have nothing to do with life.

In the future, if humans colonize aliens, because of the friendly conditions of Mars (compared with other planets, Mars is most like the Earth), it is likely to be our first choice.

There is indeed water on Mars.

On August 18, scientists from the National Aeronautics and Space Administration (NASA) announced that the Mars probe Spirit had found a new riverbed on Mars with traces of water erosion. Combined with the previous detection data of "Courage" and "Opportunity", they think that the hills and craters on Mars indicate that there were a lot of traces left by running water on Mars.

Scientists at NASA's California Jet Propulsion Laboratory said that this week, the Spirit Mars probe found a long and wide riverbed on the surface of Mars, and the riverbed was obviously washed away by water, which is also an important clue to reflect the original environment of Mars. Scientists speculate that this riverbed broke through the lava surface of a huge volcano called "Gusvi". The "Guswei" crater happened to land on the landing zone of Mars on June 38 this year+10/October 3. Last week, Spirit made a series of explorations and related tests on the rock named Clovis near the crater.

NASA scientists also stressed that although both Spirit and Opportunity found ancient evidence of water on Mars in the early days of Mars exploration, the new data recorded by Spirit instrument this time shows that there is flowing water on Mars, and the amount of water is much more than scientists had previously speculated. Scientists at NASA previously thought that the landing area where Opportunity landed on Mars was once an ocean. Opportunity is also preparing to survey sand dunes in a volcanic area called Endurance.

China news agency, Los Angeles, June 2 1 Sunday-Scientists of the National Aeronautics and Space Administration of the United States officially announced on the 20th that the luminescent substance dug up by the Phoenix Mars landing probe near the landing site is frozen water, thus confirming that there is indeed water on Mars. This is also the first time that humans have obtained frozen water samples outside the earth through detectors.

On this month 15, the Phoenix probe found some shiny cubes while digging the red soil on the surface of Mars. In the sun, these small squares disappeared after four days.

"Today, I am proud and happy to announce that we have found evidence that these hard and bright substances are really frozen water and not other substances," said peter smith, a scientist from the University of Arizona in the United States, at a news conference held in Tucson, Arizona today.

It is reported that scientists have ruled out the possibility that these cubes are dry ice or salt. Because salt does not evaporate; Carbon dioxide needs a lower temperature to become a solid (dry ice). At present, the temperature of the Phoenix landing site is about -32 degrees Celsius during the day and -80 degrees Celsius at night. In the thin atmosphere of Mars, dry ice needs a lower temperature. Peter smith said that on Mars, the boiling point of water is only four degrees Celsius, and water will evaporate rapidly at a very low temperature.

At the same time, NASA scientists revealed that the robotic arm of Phoenix hit a hard surface during the excavation on 19, and scientists judged that it was probably a bigger ice layer.

Scientists say that the truth they want to explore is not only to find water on Mars, but also to explore the minerals, chemical components and possible organic compounds on Mars.

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Earth explosion

You mean asteroids, right? This is a low probability event, although there is this possibility, but the probability of occurrence is very small, especially in the short decades of human life. So don't worry.

"Please circle April 13, 2036 on the calendar. On this day, an asteroid may hit the earth. Once the tragedy happens, it will be the end of the world for many people on earth! " At the annual meeting of the American Association for the Advancement of Science held in San Francisco recently, scientists issued such a "doomsday warning". They also openly called on the United Nations to shoulder its responsibilities and find a solution to this crisis and save all mankind. According to reports, the probability of this asteroid hitting the earth is 1/37 to one in 45,000, but in astronomy, this is already a "very high probability" and humans have to take precautions. According to the British "Sunday Telegraph" on February 25th, next month, NASA will hold a three-day "Planetary Defense Conference", at which time hundreds of scientists from all over the world will gather together to discuss specific plans to prevent asteroids from hitting the earth. At present, the plan approved by scientists is to push asteroids out of Earth orbit.

Great danger is approaching the earth.

This asteroid that has aroused the vigilance of scientists all over the world is called Apophis. In Egyptian mythology, "Apophis" is an ancient god of evil and destruction, whose purpose is to plunge the whole world into eternal darkness. Scientists also named this asteroid that came straight from outer space to the earth "Apophis", precisely because this asteroid will pose an unprecedented catastrophic threat to mankind, and it is said that its danger level is the highest among asteroids discovered so far.

Imagination of an asteroid hitting the earth

Recently, scientists attending the annual meeting of the American Association for the Advancement of Science studied the threat of asteroids to the earth and possible solutions. According to Reuters and other media reports, scientists reminded people at the meeting that the asteroid Apophis weighing 45 million tons will pass 34,000 kilometers above the earth in 2029. Although this distance seems far away, from an astronomical point of view, it is as thick as a hair and is quite dangerous to the earth. You know, the height of geosynchronous satellites from the ground is about 36,000 kilometers.

Scientists say that what is more dangerous is that the "passing by" with the earth in 2029 is likely to change the orbit of Apophis and greatly increase its chance of colliding with the earth in 2036. "If we are lucky, this planet will pass by the earth; Unfortunately, it will directly hit the earth, and the impact area is very large, almost equivalent to the whole of England. " In recent two years, there are many theories about the possibility of Apophis hitting the earth, including 1/300, 1/60, and even 1/37. Now scientists generally believe that the possibility of Apophis hitting the earth head-on in 2036 is one in 45,000, but even so, it is astronomical.

According to the scientists attending the meeting, the direct impact of this planet on the urban areas of the earth will be more destructive than the sum of Hurricane Katrina, the 2004 Indian Ocean tsunami and the 1906 San Francisco earthquake. The power generated by the impact of the planet on the earth will be equivalent to 65000 times that of the atomic bomb explosion in Hiroshima, Japan in 1945. Some scholars say that there was a similar disaster on the earth, which destroyed the ancient Egyptian civilization. Now, new threats are approaching the earth again.

Scientists call for international treaties to deal with asteroids.

On February 25th, the British "Sunday Telegraph" reported that there are about 654.38 million+asteroids in space, which are large enough to destroy a city. Unfortunately, scientists can't accurately predict all asteroids that pose a threat to the earth at present, and they can't 100% predict whether and when they will really hit the earth. Even the orbit determination of an eye-catching asteroid like Apophis is not very accurate. In fact, scientists may not be completely sure whether Apophis will hit the earth until 2029, but many experts stress that we should plan ahead: "If we wait until 2029, it is hard to say whether it will hit the earth in 2036."

Recently, the US Congress asked NASA to improve the level of asteroid tracking, but scientists expect more international cooperation.

"Every country and region on earth is facing a crisis. We should not only monitor Apophis, but also formulate a set of international strategies, norms and conventions to deal with such problems. " 1969 Former American astronaut Schweikat, who participated in the Apollo 9 mission, said that the impact of asteroids on the Earth is an international issue, and every country needs to make decisions at the international level. The United Nations has a responsibility to deal with this crisis as a whole. Considering the difficulties that the United Nations may encounter in making urgent and major decisions, Schweickart also suggested that a United Nations treaty should be drafted in the next two years, so as to specify the specific decision-making process in advance when the disaster is about to happen, instead of waiting for the meeting to discuss it after the problem arises. Schweickart said that the work of formulating such a treaty has not yet started, and he is cooperating with the United Nations Committee on the Peaceful Uses of Outer Space, hoping to promote the early publication of the treaty.

In addition, the Space Explorers Association, composed of former astronauts, also plans to launch a series of activities this year to discuss new strategies to deal with the threat of asteroids, and submit a formal proposal to the United Nations in 2009.

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An explosion of the earth is generally impossible. I don't know if you are asking about the theory of cosmic explosion.