Did you know that there is a planet in the solar system that has more water than Earth, and that its surface is shimmering with mysterious highlights? This planet is Ceres, which is located in the asteroid belt between Mars and Jupiter and is one of the largest dwarf planets in the solar system. To unravel its mysteries, scientists have developed a spaceship to travel to Ceres. Today, let's walk into this ancient celestial body and see how many secrets are hidden on Ceres.
Ceres was discovered on January 1, 1801 by the Italian astronomer Giuseppe Piazzi, who was observing the space between the orbits of Mars and Jupiter, when he suddenly discovered a bright spot, and after further observation and calculations, he determined that this bright spot was a new celestial body, about 28 astronomical units, equivalent to 4200 million km.
The appearance of this celestial body surprised scientists because it has many similarities with the Earth, such as its shape, size, water volume, etc. In 2006, the International Astronomical Union redefined Ceres as a dwarf planet, meaning that it is a celestial body with enough mass and gravity to make itself an approximate sphere, but there are other small objects around its orbit, so it cannot be considered a full planet. You know, most of the dwarf planets in the solar system are concentrated in the Coibo belt outside Neptune's orbit, such as Pluto and Orocthes. Only Ceres is an exception, it is distributed in the asteroid belt, accounting for 25% of the total mass of the entire asteroid belt, and is the largest celestial body in the asteroid belt, which is also destined to be mysterious and extraordinary.
If you put Ceres on Earth, it's about the size of Alaska in the United States, but it's only a thousandth the weight of Earth. Ceres has a diameter of about 950 kilometers, and without satellites revolving around it, it takes only 9 hours and 4 minutes to rotate around it, and the time to make one revolution is 1682 Earth days, which is 46 years. The probe found that the atmosphere on Ceres is very thin and contains nitrogen, and because Ceres is above the asteroid belt, the space environment around it is not stable, and some asteroids may hit the surface of Ceres.
To the surprise of scientists, Ceres is actually a round star in the early days of the formation of the solar system, its mass and volume are relatively small, and it is also affected by Jupiter's gravity, so the gravity of Ceres is only 2 of that of Earth75%。If you do high jump on Ceres, you can jump up to 16 meters in one easy jump, and you can fly in the air with a single jump, which is an environment that is difficult for humans to adapt to.
In order to detect the closest dwarf planet to Earth, on September 27, 2007, the Dawn space probe, costing about $450 million, was successfully launched at Cape Canaveral Base, Florida, USA. Its mission is to travel hundreds of millions of kilometers away to the asteroid belt to explore two of the largest stars, Ceres and Vesta. Scientists believe that the exploration of Ceres and Vesta will help understand the origin of the solar system and understand the formation process of the Earth and other planets, and scientists named the unmanned probe Dawn.
The Dawn probe is an extraordinary space vehicle, it has been flying in space for seven and a half years, it has experienced countless difficulties and challenges, such as it has suffered two computer failures, causing it to lose contact with the ground, but with its wisdom and courage, it has resumed normal operation and continued its exploration journey. The Dawn is equipped with advanced scientific instruments and equipment such as high-definition cameras, visible and infrared spectrometers, gamma ray and neutron detectors. In addition, three ion thrusters and two solar panels about 10 meters long are installed on Dawn, with wings nearly 20 meters apart, providing the main impetus for its space journey. Among them, the ion thruster converts solar energy into electrical energy, and then ionizes the atoms of the noble gas xenon through the electrical energy, producing a speed of up to 143 20,000 km of ion current. As a driving force, this technology has taken space probes to a new level.
After four years of flying, the Dawn probe reached its first target, Vesta, on July 16, 2011. Vesta is the second largest asteroid in the solar system, it has a diameter of about 530 kilometers, its surface is full of traces of volcanic activity, and scientists believe it is an active world that may have a lava core. The Dawn probe has been orbiting Vesta for more than a year, taking thousands of shots** and collecting a lot of scientific data. It discovered some peculiar phenomena on Vesta, such as some huge peaks on its surface, the highest of which is 22 kilometers high, making it one of the highest peaks in the solar system; It also has some deep fissures on its surface, the longest of which is 500 kilometers long, making it one of the longest fissures in the solar system; It also has some bright spots on its surface, which scientists speculate may have been formed by salt or ice.
On September 5, 2012, the Dawn probe left Vesta for its second mission, to Ceres. After two and a half years of flying, the Dawn probe entered the orbit of Ceres on March 6, 2015 as planned, began scientific exploration of the mysterious planet, and photographed the first image of Ceres in human history. It shows that Ceres is a relatively regular sphere with craters on its surface. When the Dawn probe successfully arrived at Ceres, the first thing to know about was the bright white bright spots on Ceres, because these bright spots have bothered scientists for a long time, so Dawn took thousands of photos** when it first approached Ceres and sent them back to the ground. The mysterious highlight we see now is located in the area of the Okato Crater, which was formed about 22 million years ago and has a diameter of about 92 kilometers.
Scientists have shown that the Okato crater contains bound minerals of water molecules, and it is likely to be a salt deposit. These bright spots are caused by salt deposits, as some salts reflect strongly from sunlight. And there are more than a hundred bright spots like this on Ceres, many of which have large amounts of water ice in them, especially in the polar regions.
In 2014, scientists detected water vapor emissions on several of these highlights, suggesting that Ceres may contain large amounts of liquid water beneath the surface, and that the water inside has sublimated. Further observations revealed that there is likely to be a liquid ocean in the interior of Ceres, with about 40% of the entire planet's water content, which is a major discovery for humans. Researchers speculate that there may be two specific reasons for the water vapor, one is that the ice on the surface of Ceres is rapidly heated by the sun's irradiation, and the other is that there is still energy inside Ceres. You know, Ceres is about the same age as Earth, with a history of nearly 4.6 billion years. Judging from the observational data, the possibility of life on Ceres cannot be ruled out. Therefore, it has been proposed to build a scientific research base on Ceres to improve humanity's ability to explore the Jupiter and Saturn systems in the future.
Through the close detection of Dawn, it is known that the diameter of Ceres is about 950 kilometers, and there are no satellites revolving around it, and it only takes 9 hours and 4 minutes to rotate around it, and the time to rotate one revolution is 1682 Earth days, which is 46 years. The probe found that the atmosphere on Ceres is very thin and contains nitrogen, and because Ceres is above the asteroid belt, the space environment around it is not stable, and some asteroids may hit the surface of Ceres.
In 2017, NASA published a scientific report on Ceres in an American scientific journal. The report noted that the Dawn probe found traces of organic compounds in a crater in Ceres' northern hemisphere, a news that shocked the astronomical community. Although scientists say the molecular structure of the organic matter cannot yet be determined, it is certain that the organic matter is similar to asphalt rock. Fearing that some form of life might exist on the surface of Ceres, NASA decided to find an optimal orbit for Dawn to ensure that it would orbit Ceres for the next 50 years without falling on its surface. After orbiting Ceres for more than two years, the Dawn probe descended to 35 kilometers above the surface of Ceres between June and October 2018 to complete missions such as imaging infrared spectroscopy, elemental spectroscopy and gravitational science with unprecedented resolution.
On October 31, 2018, Dawn ran out of fuel and lost contact with ground controllers, ending its extraordinary mission. In its 11 years of space exploration, it has sent back more than 100,000 pieces of ** and scientific data information to mankind. It was the first probe to use ion thrusters and the first man-made vehicle to visit Ceres up close. It provides valuable scientific data for the origin and evolution of the solar system, and has made great contributions to human exploration of Ceres.
In conclusion, Ceres is a one-of-a-kind world, serving as a snapshot of the early days of the solar system's formation, which can help us understand the history and evolution of the solar system, as well as the origins of the Earth and other planets. NASA's Dawn project scientist Carol Raymond said, "Ceres is an active world, and it could be another place of life in the solar system besides Earth. "So our human exploration of Ceres is far from over, and there are still many unknown secrets waiting to be discovered. Maybe one day, we can land on this ancient planet in person and feel its charm and magic.
February** Dynamic Incentive Program