Possibly, comets brought water to Earth
To see exactly what is in the comet, it is necessary to analyse its substance with the help of different high sensitive devices, bringing samples to Earth. But aboard a small spacecraft such devices are difficult to place, because the size of the station Stardust 1,7×0,7×0,7 meters – about the same size as the Desk. How to take a sample of matter, flying from the comet’s nucleus at high speed? Space standards Stardust was moving slowly relative to the comet, about one and a half times slower than fly around the Earth artificial satellites. However, even this speed was several times greater than that of the bullet, the station flew over one second 6 km from the Contact of dust particles with the container of solid material at this speed (more than 20 thousand km/h) would have led to their strongest heating and evaporating. The only way to mildly catch and stop these dust particles, turned out to be a trap made of unique material – aerogel, which was established in 1931, but the big distribution has not received. Continue reading
At the end of last week in Ulyanovsk has started an interesting project Simple science. Its initiator is the teacher of UVAU HA Leonid Podymov.
— The main purpose of my lectures is to educate. I would like to tell Ulyanovsk on the latest and most interesting achievements in modern science into simple language so that it is clear even to the unprepared listener, — says the organizer of the “Simple science”.
Leonid physicist by education, so the project is focused mainly on natural Sciences. In particular, the first lecture was devoted to astronomy — or rather, cosmic distances and scale.
— Many people know that, for example, our Solar system is big. But it is actually an ordinary person is unlikely to adequately represent these scales and distances — simply because it is not something to compare. I tried using a few simple techniques to bring clarity in such comparisons, says the teacher.
So, during the speech he invited the audience to spend with him a few thought experiments.
— Let’s imagine that our planet has shrunk to the size of a standard basketball ball whose radius 12.2 centimeters. If we reduce all other razmery accordance with a given scale, we get the following illustrative figures: the Sun will be a ball with radius 13 meters. Continue reading
Periodic comet attracted by the Sun, sent to him, but pass due to the same sensitivity to the solar wind, which causes the surrounding cloud of dust and gases blown away from the Sun. People believe that the tiny particles of solar wind will impact more than large particles, but this assumption is wrong. If this were so, then how to explain the continued existence of the Asteroid Belt, which includes debris of any size is not affected, apparently, by the solar wind. The small object may lose velocity faster than the larger object because of differences in gravity, but if they are sensitive to solar wind, it occurs the same effect, – they are repelled equally. The comet, which (eventually) reach the Sun, with a very repeatable trajectory around the Sun, losing a lot of water vapor so that the ratio of substances in their composition is aligned at the expense of pushing away by the solar wind. In short, they lose their cover. They fly up with acceleration from the external space, but at this time do not change direction, going outside, and face (with the Sun). In fact, comets complete their orbits, coming nearer in the process, getting closer and closer to the Sun. Continue reading