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
Modern physics. A flight to Mars.
Russia is technically ready to organize a manned mission to Mars in early 2020-ies, the Director of the space research Institute of Russian Academy of Sciences the academician the lion Green.
“Priority for Russia, and prestigious really the first to disembark an astronaut on Mars. This problem is economically and technically solved”, — said L. Green. According to him, if to begin preparations for flight in the near future, Russian cosmonauts can land on the surface of Mars in 2023-2025 years.
For the organization of the expedition, says L. Green, hurt Russia more than any other country, including the United States.
“We now have a certain handicap in this race, as we have the biggest experience in manned space exploration. Even in the bad 90’s, he worked as the station “Mir”, then there was the ISS. Thus a chain of manned flights have not been interrupted,” — said the scientist. Continue reading
So far the only scientifically proven the possibility of interstellar travel is the acceleration of the spacecraft up to relativistic speeds (punctures and convolution space still remain purely speculative projects). The ship may abandon astronauts in suspended animation for a dozen or even a hundred light years and return them to Earth. But because of the relativistic slowing of Board time on earth will pass away not even the century and Millennium — and it is somehow not pleasing. In addition to other galaxies to get to, there’s no cryostasis will not help. But it is possible that the output is still there.
For 15 years Professor of theoretical physics at Imperial College London, Joao Magueijo develops the hypothesis of variable speed of light (Varying Speed of Light, VSL). However, he minded very little, since most scientists believe this idea is pure nonsense. But we are talking about science impossible, so will try to temper my skepticism.
VSL-models calculated in several ways. They all say that measured on Earth the speed of light in a vacuum is not an absolute constant, and only the lower limit of the speed of propagation of electromagnetic waves. In certain (frankly, vesimaailma) conditions may be many times 299 792 km/s. Continue reading