The planet Mars is one of the brightest objects in our night sky, even visible to the naked eye and resembles a bright red star. About every two years, our planet and Mars is a maximum converging. Such an event in astronomy is called “confrontation”. At this point, Mars will be only fifty-five millions of miles from Earth. People capitalize on that by sending to the Red Planet during the confrontation spaceships. So how much to fly to Mars ?
The orbit of Mars and Earth
The complete journey from Earth to Mars takes between 150 to 300 days to allow for the speed run, the location of the planets and the length of the path, which must pass the spacecraft. In this case the dominant factor is only the amount of fuel. The more fuel, the faster it will take flight.
History of flights to Mars
The first ever space ship, committed trip Earth-Mars, was created by NASA’s Mariner 4. It was launched in late November 1964 and appeared on Mars July 14, 1965. Mariner 4 reached Mars in 228 days. Continue reading
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
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Inside the comet 67P/Churyumov — Gerasimenko there are no large voids. The mission of “Rosetta” the European space Agency made measurements that clearly demonstrated and solved the old mystery. Comets are icy debris left over from the formation of the planets 4.6 billion years ago. Spacecraft have visited a total of eight comets, and through these missions we pulled a picture of the basic properties of these space-time capsules. On some questions the answers were found, others appeared.
Comets, as we know, consist of a mixture of ice and dust, and if there were compact, gravity superior to water. However, previous measurements have shown that some of them have very low density, much lower than water ice. Low density means that the comet must be extremely porous.
But what is this porosity: due to large voids in the subsurface of the comet, or due to a more homogeneous structure with low density? Continue reading