Unlike planets, comets move on highly elongated orbits, and therefore are visible only at short periods close to the Sun.
The main part of any comet is its nucleus .
According to the hypothesis of the famous American researcher of comets Fred Lawrence Whipple, cometary nucleus is an ice consisting of a mixture of frozen water and frozen gases interspersed with refractory rocky and metallic particles . Figuratively speaking, it looks like a “dirty iceberg”.
Let us imagine that we see the newly opened the comet, which is somewhere in the vicinity of Jupiter’s orbit. Seeing through the telescope hazy pale speck, like a spherical nebula (such unattractive are presented to the observer of a distant comet), we may be disappointed at first. With the approach of the comet to the Sun the solar flux increases. Comet “ice” begin to evaporate rapidly. Around the nucleus formed a vast glowing gas shell – coma. Together with the core of it is the head of the comet. Continue reading
Now we prove the existence of 1783 planets in 1105 planetary systems. And the number of candidates is approaching three thousand. All in all, scientists assume that in our galaxy the milky Way is at least 100 billion exoplanets!
People have long realized that other stars, like the Sun, can have their own planet. And even gave them the name exoplanets or extrasolar planets, i.e. planets outside our Solar system. But to verify the existence of such planets a science was only in the late 1980s. Now it is proved the existence of 1783 planets in 1105 planetary systems. And the number of candidates is approaching three thousand. All in all, scientists assume that in our galaxy the milky Way is at least 100 billion exoplanets. 5-20 billion of them earth-like. Some of the most remarkable exoplanets.
Minitems, that is, exoplanets, which are less in size small even our Earth, Kepler-42 d (also known as KOI-961 d) revolves around the star Kepler-42 in the constellation Cygnus. The radius of the planet is just 0,57 ± 0,18 from the earth’s mass and less than 90 % of the mass of our planet. One year, one revolution around its star, Kepler-42 d lasts for less than 2 earth days. Continue reading
Of course, the oceans are huge and mountains impress with their value. And seven billion people is a lot, but still. Since we all live on planet Earth (whose diameter is 12 742 km), it is easy to forget how insignificant we really are small. All we need to do is look up at night, the sky, and realize that we are just a bunch of dust in the immeasurable vast Universe.
10. Jupiter. The largest planet (142 984 kilometres in diameter)
Jupiter – the largest planet of our Solar System. Ancient astronomers named Jupiter after the main Roman God. Jupiter is the fifth most close planet to the Sun. The atmosphere of Jupiter consists of about 84 percent hydrogen and about 15 percent helium, with small amounts of acetylene, ammonia, ethane, methane, phosphine, hydrogen and water vapor. Jupiter has a mass 318 times the mass of Earth and a diameter 11 times larger than the diameter of the Earth. The mass of Jupiter is 70% of the total mass of all other planets of our Solar System. The volume of Jupiter is large enough that it could fit 1300 planets the size of Earth. The planet has 63 known satellites (moons) but most of them have very small sizes, and disappear. Continue reading