Astronomers have detected our “grotesque” twin: A planetary system arranged much like our own solar system, a new study says 다운로드.
Dubbed GJ676A, the system has two rocky planets orbiting close to its host star, and two gas giants orbiting far away. This means the system is arranged like our system—though in GJ676A, everything is much larger 다운로드.
For instance, the smallest rocky planet in GJ676A is at least four times the mass of Earth, while the largest gas giant is five times the size of Jupiter 다운로드.
Other multiple-planet systems have been discovered, such as HD10180, which has been called the richest exoplanetary find ever because of the seven to nine planets orbiting its host star c920 드라이버 다운로드.
But HD10180’s planets are all gas giants in relatively close orbits, while GJ676A has both rocky and gas planets—and its “Neptune-like” planet takes 4,000 days to make one orbit 프리 뮤직 다운로드.
The long orbits of GJ676A’s gas giants and the short orbits of its close-in, extremely hot super Earths are what led the astronomers to dub GJ676A our solar system’s twin ncs 학습모듈.
Source: National Geographic News – Solar System’s “Grotesque” Twin Found
How big is Jupiter’s moon Io?
The most volcanic body in the Solar System, Io (usually pronounced “EYE-oh”) is 3,600 kilometers in diameter, about the size of planet Earth’s Moon 레밍즈 게임.
Gliding past Jupiter at the turn of the millennium, the Cassini spacecraft captured this awe inspiring view of active Io with the largest gas giant as a backdrop, offering a stunning demonstration of the ruling planet’s relative size 텝스 기출 문제 다운로드.
Io hurtles around its orbit once every 42 hours at a distance of 420,000 kilometers or so from the center of Jupiter. That puts Io nearly 350,000 kilometers above Jupiter’s cloud tops, roughly equivalent to the distance between Earth and Moon 찬양하세 다운로드.
The Cassini spacecraft itself was about 10 million kilometers from Jupiter when recording the image data.
Does the Moon rotate?
And if the Moon rotates, why do we alway see the same side – it never seems to change.
Well, the Moon does rotate 다운로드. In fact, the Moon takes 27.3 days to turn once on its axis. But the Moon also takes 27.3 days to complete one orbit around the Earth. Because the Moon’s rotation time is exactly the same amount of time it takes to complete an orbit, it always presents the same face to the Earth, and one face away (the Dark Side) 타로카페 다운로드.
Because it only presents one face to the Earth, astronomers say that the Moon is tidally locked to the Earth. Although the Moon looks like a perfectly smooth ball, it has slight differences in the shape of its gravity field 배치 파일. A long time ago, the Moon did rotate. But each time it turned, the Earth’s gravity tugged at it, slowing down its rotation until it only presented one face to the Earth 다운로드. At that point, the Moon was tidally locked, and from our perspective, it doesn’t seem to rotate.
Many other moons in the Solar System are also tidally locked to their planet 헬싱 ova 다운로드. In fact, most of Jupiter’s large moons are tidally locked.
via Universe Today