In space, no one can hear you scream. This is because there is no air in space – it is a vacuum. Sound waves cannot travel through a vacuum. 'Outer space' begins about 100 km above the Earth, where the shell of air around our planet disappears.
What is the main gas on the moon?
The Apollo 17 mission deployed an instrument called the Lunar Atmospheric Composition Experiment (LACE) on the moon's surface. It detected small amounts of a number of atoms and molecules including helium, argon, and possibly neon, ammonia, methane and carbon dioxide.
So, the Sun can "burn" hydrogen to helium without the need for oxygen. It should be noted that in the presence of carbon, nitrogen and oxygen, stars heavier than the Sun may burn hydrogen to helium by using the C, N and O as catalysts. Even in these stars, however, an absence of oxygen does not prevent nuclear burning.
At most, an astronaut without a suit would last about 15 seconds before losing conciousness from lack of oxygen. (That's how long it would take the body to use up the oxygen left in the blood.) Of course, on Earth, you could hold your breath for several minutes without passing out.
What is space made of? Space that we can see is mainly very very empty. If you ignore the galaxies and stars, then the rest of space is mainly a vacuum, so there's no particles at all. The particles that are there are mainly hydrogen and helium, which form a plasma called the Intergalactic Medium.
Astronomers think space might be infinite, with "stuff" (energy, galaxies, etc.) distributed pretty much the same as it is in the observable universe. If it is, that has some seriously weird implications for what lies out there. Beyond the Hubble Volume you won't just find more, different planets.
Some people think that there is no gravity in space. In fact, a small amount of gravity can be found everywhere in space. Gravity is what holds the moon in orbit around Earth. Gravity causes Earth to orbit the sun.
Recent tests aboard the International Space Station have shown that fire in space can be less predictable and potentially more lethal than it is on Earth. “There have been experiments,” says NASA aerospace engineer Dan Dietrich, “where we observed fires that we didn't think could exist, but did.”
When flames burn on Earth, heated gases rise from the fire, drawing oxygen in and pushing combustion products out. Space flames can also burn at a lower temperature and with less oxygen than fires on Earth. As a result, the material used to put out space fires must be more concentrated, researchers said.
Water poured into space (outside of a spacecraft) would rapidly vaporize or boil away. In space, where there is no air, there is no air pressure. That's why water boils much faster on a mountaintop than it does at sea level. In space, because there is no air pressure, water boils away at an extremely low temperature.
The heat/energy will be dissipated into space and the oxygen molecules will slow down and travel until they find a new "place" to be used. There can be oxygen in space, but there is no atmosphere to hold it together to be used by humans. It just works like a balloon here on earth.
Outer space has very low density and pressure, and is the closest physical approximation of a perfect vacuum. But no vacuum is truly perfect, not even in interstellar space, where there are still a few hydrogen atoms per cubic meter.
We breathe by expanding our lungs. As long as the air around us is thick enough we can breathe, regardless of gravity. On Earth, gravity is what holds our atmosphere. When astronauts go into space they can breath, because their space ships and space suits keep the air around them, even though gravity is very weak.
Never mind the moon s utter lack of atmosphere, there s plenty of air to breathe up there—provided you know where to look. It is the moon s small mass and low gravity that prevents it from keeping hold of even a tenuously thin atmosphere. But oxygen needn t exist only in gaseous form above the ground.
Outer space does not begin at a definite altitude above the Earth's surface. However, the Kármán line, at an altitude of 100 km (62 mi) above sea level, is conventionally used as the start of outer space in space treaties and for aerospace records keeping.
The sun has used up about half of its hydrogen fuel in the last 4.6 billion years, since its birth. The sun burns using a nuclear fusion process, combining hydrogen into helium. When the sun runs out of hydrogen, it will fuse helium and other heavier elements until it runs out of fuel.
Electrolysis of water (H2O) is the main method to generate oxygen aboard the ISS. Water is split into oxygen (O2) and hydrogen (H2). The oxygen is vented into the breathable cabin air system, known as the Oxygen Generation System, while the explosive hydrogen is vented externally.
The actual density of hydrogen as it exist in interstellar space is on the average of about 1 atom per cubic centimeter. In the extremes, as low as 0.1 atom per cubic centimeter has been found in the space between the spiral arms and as high as 1000 atoms per cubic centimeter are known to exist near the galactic core.
Space physics. Space physics is the study of plasmas as they occur naturally in the Earth's upper atmosphere (aeronomy) and within the Solar System.
But inside the International Space Station (ISS), the American astronauts and Russian cosmonauts do breathe air almost identical to the stuff we breathe down here on planet Earth - same pressure and about 80 per cent nitrogen and 20 per cent oxygen. It turns out they get it by 'splitting' H2O with electricity.