Vacuum outer space

In a vacuum, uncoated molybdenum metal has an unlimited life at high temperatures. This is also tme under the vacuum-like conditions of outer space. Pure hydrogen, argon, and hehum atmospheres are completely inert to molybdenum at all temperatures, whereas water vapor, sulfur dioxide, and nitrous and nitric oxides have an oxidizing action at elevated temperatures. Molybdenum is relatively inert to carbon dioxide, ammonia, and nitrogen atmospheres up to about 1100°C a superficial nitride film may be formed at higher temperatures in the latter two gases. Hydrocarbons and carbon monoxide may carburize molybdenum at temperatures above 1100°C. 

If metal surfaces are thoroughly cleaned in vacuum it is almost impossible to slide them over each other. Any shearing force causes further plasticity at the junctions, which quickly grow, leading to complete seizure (p > 5). This is a problem in outer space, and... 

Nowadays, there doesn t really exist a liquid, condition, or pump operating situation that cannot be sealed suecessflilly with a mechanical seal. With the help of mechanical seals, man has been able to explore the extreme pressures of the oeean depths, and the extreme vacuum of outer space. 

Nature abhors a vacuum. True On Earth, it is certainly difficult to remove the gas from a container, thereby generating and maintaining a vacuum—the absence of gas. In outer space, on the other hand, a vacuum is the mle rather than the exception. Most of the volume of the universe is nearly empty space, close to a perfect vacuum. If a spacecraft sprang a leak, its gaseous atmosphere would quickly escape into that vacuum. Perhaps it would be better to say that conditions on Earth are unfavorable for vacuums. 

Why bother to remove the gases from a small volume of space High vacuum Is used In chemistry and physics research to achieve any of the following conditions the absence of molecular collisions, the maintenance of an ultraclean environment, or a simulation of conditions in outer space. 

These reactions take place very slowly under the extreme ultra-high vacuum conditions present in outer space, so that the chemistry is different to that observed in the laboratory. Thus there are still some open questions regarding the mysterious interstellar ion H3+, particularly with respect to its occurrence in diffuse clouds and its rate of decomposition (Suzor-Weiner and Schneider, 2001 Kokoruline et al., 2001). 

Table 11.1 Survival of Bacillus subtilis spores subjected in different missions to the ultra-high vacuum conditions (10 6—10 4 Pa) prevalent in outer space (Horneck et al., 2002b)...

The perfeci vacuum doesn t exist. There are always some molecules around-even in outer space. Space comes closest to a vacuum, though, with just a few hydrogen atoms per cubic inch (centimeter) of space. So scientists usually use the term partial vacuum instead of perfect vacuum. ... 

Compositions are also important in the construction of objects to both propel material into outer space and exist there. Because of the large amount of fuel required to propel spacecraft into outer space, weight reduction, offered by composites, is essential. The polymeric nature of composites also makes it an ideal material to resist degradation caused by the vacuum of outer space. 

The word vacuum in the English language is the same as the Latin word meaning a completely empty space. In practice, the word vacuum is used to describe any space in which the pressure is less than atmospheric pressure. Further, in order to specify the quality of a vacuum, various adjectives are used. Table 1.1. lists a selection of these terms, the associated pressure range, and the number of molecules per cubic centimetre that such a vacuum contains. It is clear that even the best known vacuum, in outer space, is not absolute. A knowledge of the amount of gas in a reaction volume at the operating pressure allows an assessment to be made of its possible effect on the reaction taking place. 

Rather, it gradually thins to the near vacuum of outer space. More than half of the atmospheres mass lies below an altitude of 5.6 kilometers, and about 99 percent lies below an altitude of 30 kilometers. 

Aside from earthbound technological approaches to achieve a vacuum, the further away from the earth s surface you go, the less atmosphere there is and therefore the greater the vacuum (relative to atmospheric pressure on the earth s surface) that can be achieved. In fact, on earth, someone standing on top of Mt. McKinley experiences vacuum greater than can be created with a standard vacuum cleaner at sea level.1 Table 7.1 shows the approximate miles above earth to obtain various conditions of vacuum. As this table shows, outer space offers wonderful opportunities to produce vacuum conditions for experimental or industrial... 

Because a perfect vacuum cannot be achieved, and the next best thing (outer space) is for all intents and purposes out of reach, there are definable limits to the ultimate pressure of any system you are planning. These limits are based on ... 

Condensed phases—solids and liquids—must have surfaces or interfaces. The suit of an astronaut maneuvering in outer space represents a solid-vacuum interface (Fig-... 

To give a quantitative idea of just how dilute the matter in outer space is, consider that roughly 2.5 x 10 particles, typically atoms, occupy 1 cm (1 mL) of volume in the Earth s atmosphere. In outer space there is, on average, only one single particle in this same volume. Outer space is a much better vacuum than even the best vacuums ever created on Earth ... 

Vacuum is measured relative to atmospheric pressure. Outer space is close to absolute vacuum the pressure is close to 0 bar but the vacuum is approximately... 

Like all atoms and molecules in a gas, the atoms and molecules in outer space are in constant motion and so can collide with each other. Compared to the billions of collisions per second in the gas phase at atmospheric pressure on Earth, however, the interstellar particles can collide only occasionally, perhaps only once a day. They exist in a better vacuum than we can create... 

It is noted that at present the Moon is surrounded by vacuum. If the Moon had gases before, they had escaped into the outer space many years ago. So, the Moon has no life now. 

---