In space, room temperature
It is believed that the temperature in space tends to absolute zero. Firstly, this is not entirely true, since the entire known Universe is heated to 3 K by relic radiation. Secondly, there is practically no temperature directly near the vacuum, and we can only talk about the temperature of any objects in space: satellites, astronauts, or simply thermometers. And their temperature will depend on two sources: external, for example, radiation from a nearby star, and internal - energy release from the operation of devices or digestion of food.
It is clear that the closer to the star, the more energy can be obtained from it and the temperature rises. And we live quite close to the Sun. For example, the temperature of an absolutely black body (a hypothetical body that reflects nothing and absorbs all solar radiation that hits it) at the distance of the Earth from the Sun will be + 4 ° С. Spacesuits and spacecraft need strong thermal insulation to maintain a comfortable operating temperature inside, so as not to overheat in the light and not to overcool in the shade.
In the shade and in a vacuum, the temperature can really drop to -160 ° C, for example, at night on the moon. It's cold, but it's still a long way to absolute zero. And even this does not happen in low-earth orbit, since both people and satellites produce their own heat, and thermal insulation does not allow quickly losing the heat that was accumulated on the illuminated side.
Here, for example, the readings of the onboard thermometer of the TechEdSat satellite , which rotated in low-earth orbit:
It was also influenced by the earth's atmosphere, but overall, the graph does not show the terrible conditions that are usually imagined in space. The readings range from -4 ° C to + 45 ° C, which on average gives almost room temperature.
Lead snow falls in places on Venus
This is probably the most startling fact I have learned about space not too long ago. Conditions on Venus are so different from anything that we could imagine that Venusians could safely fly to earthly hell to relax in a mild climate and comfortable conditions. Therefore, no matter how fantastic the phrase "leaden snow" may seem, for Venus it is a reality.
Thanks to the radar of the American Magellan probe in the early 90s, scientists discovered a kind of coating on the tops of the Venusian mountains that has a high reflectivity in the radio range. At first, several versions were assumed: the consequence of erosion, the deposition of iron-containing materials, etc. Later, after several experiments on Earth, they came to the conclusion that this is the most natural metallic snow, consisting of bismuth and lead sulfides. In a gaseous state, they are emitted into the planet's atmosphere during volcanic eruptions. Then, thermodynamic conditions at an altitude of 2600 m favor the condensation of compounds and precipitation at higher elevations.
There are 13 planets in the solar system ... or more
When Pluto was demoted from the planets, it became a rule of good form to know that there are only eight planets in the solar system. True, at the same time, a new category of celestial bodies was introduced - dwarf planets. These "sub-planets", which have a rounded (or close to it) shape, are not anybody's satellites, but at the same time they cannot clear their own orbit from less massive competitors. Today it is believed that there are five such planets: Ceres, Pluto, Hanumea, Eris and Makemake. The closest to us is Ceres. In a year, we will learn much more about her than we do now, thanks to the Dawn probe. So far we only know that it is covered with ice and water evaporates from two points on the surface at a rate of 6 liters per second. We will also learn about Pluto next year, thanks to the New Horizons station. In general, as 2014 in cosmonautics will become the year of comets,
The rest of the dwarf planets are located beyond Pluto, and we will not know any details about them soon. Just the other day , another candidate was found, although he was not officially included in the list of dwarf planets, as was his neighbor Sedna. But it is possible that they will find more, several larger dwarfs, so the number of planets in the solar system will still grow.
The Hubble telescope is not the most powerful
Thanks to the enormous volume of imagery and the impressive discoveries made by the Hubble telescope, many have the idea that this telescope has the highest resolution and is able to see details that cannot be seen from Earth. For a while it was: despite the fact that large mirrors can be assembled on Earth on telescopes, the atmosphere introduces a significant distortion in the images. Therefore, even a "modest" by earthly standards mirror with a diameter of 2.4 meters in space, allows you to achieve impressive results.
However, over the years since the launch of Hubble, earth astronomy has not stood still, several technologies have been worked out that allow, if not completely get rid of the distorting effect of air, then significantly reduce its impact. The Very Large Telescope of the European Southern Observatory in Chile can provide the most impressive resolution today. In optical interferometer mode, with four primary and four auxiliary telescopes working together, it is possible to achieve a resolution of about fifty times that of Hubble.
For example, if Hubble gives a resolution on the Moon of about 100 meters per pixel (hello to everyone who thinks that this is how Apollo lander can be viewed), then VLT can distinguish details up to 2 meters. Those. in its resolution, American descent vehicles or our lunar rovers would look like 1-2 pixels (but they will not look because of the extremely high cost of working time).
A pair of Keck telescopes, in interferometer mode, are capable of 10 times the Hubble resolution. Even individually, each of Keck's ten-meter telescopes, using adaptive optics technology, is able to outperform Hubble in two times. For example, a photo of Uranus:
However, Hubble does not remain without work, the sky is large, and the scope of the space telescope camera exceeds the terrestrial capabilities. And for clarity, you can see a complex, but informative graph .
Bears in Russia are 19 times more common than asteroids in the Main Asteroid Belt
The American popular science website sites , and Computerra translates curious calculations that show that travel in the asteroid belt is not as dangerous as George Lucas thought. If all asteroids larger than 1 meter are placed on a plane equal to the area of the Main Asteroid Belt, then it turns out that one stone is about 3200 square kilometers.
100 thousand bears of Russia should be distributed one by one for every 170 square kilometers of territory. Of course, both asteroids and bears try to stay closer to themselves and defile pure mathematics with their uneven distribution, but for the sake of a holiday, such trifles can be neglected.