How cold is it in outer space? (2024)

FAQs

How cold is it in outer space? ›

Space is very, very cold. The baseline temperature of outer space is 2.7 kelvins — minus 454.81 degrees Fahrenheit, or minus 270.45 degrees Celsius — meaning it is barely above absolute zero, the point at which molecular motion stops.

Your body would take between 18-36 hours to freeze in space due to the radiational cooling. There are other problems when it comes to being stranded in space though. While freezing is not your most immediate concern, oxygen and extreme low pressure are things to be concerned about.

Space, however, is a vacuum—meaning it's basically empty. Gas molecules in space are too few and far apart to regularly collide with one another. So even when the sun heats them with infrared waves, transferring that heat via conduction isn't possible.

Spacesuit insulation technologies protect the astronaut from extreme high and low temperatures of the space environment. However, the same insulation technology also works to keep heat released by the astronaut's body inside the suit.

Astronauts on the ISS experience both weaker gravity and higher velocity, resulting in slightly slower ageing compared to people on Earth. The European Space Agency (ESA) explained in a tweet that “after spending six months on the ISS, astronauts have aged about 0.005 seconds less than the rest of us.”

When released into space, water boils until it freezes. Space is cold, about –454° F (–270° C). Even though the water may be cool when released into space, it will boil immediately because of the nearly non-existent atmospheric pressure.

3 cosmonauts on the Soyuz 11 mission who died in 1971 when returning from a Soviet space station. Their return capsule suffered an accidental decompression. However, their bodies were returned to Earth since the capsule was fully automated. So there are currently no bodies in space.

How long can you survive in outer space? Without a space suit, you'd lose consciousness in about 15 seconds, die after 90 seconds and freeze solid within 12 to 26 hours.

Your blood holds enough oxygen for about 15 seconds of brain activity. After that you'd black out, with complete brain death following within three minutes.

Overall, astronauts often compare the smell of space to "hot metal, burnt meat, burnt cakes, spent gunpowder and welding of metal," according to Steve Pearce, a biochemist and CEO of Omega Ingredients, who combed through astronaut interviews to help him craft a NASA-commissioned scent.

How long can you survive in space without a suit? ›

The short answer is, not very long. "Within a very short time, a matter of 10 to 15 seconds, you will become unconscious because of a lack of oxygen," according to Stefaan de Mey, a senior strategy officer at the European Space Agency (ESA) charged with coordinating the strategy area for human and robotic exploration.

The environment of space is lethal without appropriate protection: the greatest threat in the vacuum of space derives from the lack of oxygen and pressure, although temperature and radiation also pose risks. The effects of space exposure can result in ebullism, hypoxia, hypocapnia, and decompression sickness.

On Earth, liquids boil at a lower temperature when there's less atmospheric pressure; outer space is a vacuum, with no pressure at all; hence the blood boiling idea. But your blood is locked up in a closed circulatory system, so it's protected from the elements (or lack thereof).

A human being can only survive for a few minutes in outer space without a spacesuit, even if they are not exposed to direct sunlight. The main reasons for this are: Oxygen deprivation: The vacuum of space does not contain any oxygen, so the human body will quickly start to suffocate.

Stellar black holes are very cold: they have a temperature of nearly absolute zero – which is zero Kelvin, or −273.15 degrees Celsius. Supermassive black holes are even colder. But a black hole's event horizon is incredibly hot. The gas being pulled rapidly into a black hole can reach millions of degrees.

Conduction and convection can't happen in empty space due to the lack of matter and heat transfer occurs slowly by radiative processes alone. This means that heat doesn't transfer quickly in space.

At best, space is only cold some of the time – at least in the direct vicinity of Earth. So if you were to step out of the ISS without a spacesuit, you would not instantly turn into a popsicle as some blockbuster movies suggest, even at the coldest points in the orbital cycle.

Just as your blanket keeps your body heat in so you stay warm in bed, NASA space suits have insulation systems as well as heaters.