Far outside our solar system and out past the distant reaches of our galaxy—in the vast nothingness of space—the distance between gas and dust particles grows, limiting their ability to transfer heat. Temperatures in these vacuous regions can plummet to about -455 degrees Fahrenheit (2.7 kelvin). Are you shivering yet?
But understanding how cold is space, and why the vacuum of space is this cold, is complicated.
For physicists, knowing what the temperature in space is is all about velocity and motion. “When we talk about the temperature in a room, that’s not the way a scientist would talk about it,” Jim Sowell, an astronomer at the Georgia Institute of Technology, tells Popular Mechanics. “We would use the expression ‘heat’ to define the speeds of all the particles in a given volume.”
⚠️ Most scientists use the kelvin instead of Fahrenheit to describe extremely cold temperatures, so we’ll be doing that here, too.
Most, if not all of the heat in the universe comes from stars like our sun. Inside the sun, where nuclear fusion occurs, temperatures can swell to 15 million kelvin. (On the surface, they only reach up to about 5,800 kelvin.)
The heat that leaves the sun and other stars travels across space as infrared waves of energy called solar radiation. These solar rays only heat the particles in their path, so anything not directly in view of the sun stays cool. Like, really cool.
At night, the surface of even the closest planet to the sun, Mercury, drops to about 95 kelvin. Pluto’s surface temperature reaches about 40 kelvin. Coincidentally, the lowest temperature ever recorded in our solar system was clocked much closer to home. In 2009, scientists measured the depths of a dark crater on the surface of our moon and found that temperatures dropped to about 33 kelvin, according to New Scientist.
That’s super cold, as in -400 Fahrenheit degrees.
Empty Space?
But our universe is vast—unimaginably vast. (And possibly a loop?) What about the vacuum of space?
Well, that’s where things get tricky. Within near and distant galaxies, the mesh of dust and clouds that weaves between the stars has been observed at temperatures between between 10 and 20 kelvin. The sparse pockets of space that contain little but cosmic background radiation, leftover energy from the formation of the universe, hover in at around 2.7 kelvin.
These temperatures dip perilously close to an elusive measurement: absolute zero. At absolute zero, which is -459.67 degrees Fahrenheit, no motion or heat is transferred between particles, even on the quantum level.
In the vacuum of space, gas particles are few and far between—about one atom per spoonful, or 10 cubic centimeters, according to Quartz—so they aren’t able to readily transfer heat to each other through conduction and convection. Heat in space can only be transferred through radiation, which regulates how particles of light, or photons, are absorbed or emitted, according to UniverseToday.
The farther you travel into interstellar space, the more you understand how cold space is. “I don’t know that you’ll ever get down to absolute zero,” Sowell says. “You’re always going to see some light and there’ll be some motion.”
There may be pockets of the universe where temperatures drop to 1 kelvin above absolute zero, Sowell notes, but so far, the closest measurement to absolute zero has only been observed in laboratories here on Earth.
“Humans are actually pretty good at creating extreme temperatures,” Alasdair Gent, a graduate student in astroparticle physics also at the Georgia Institute of Technology, tells Popular Mechanics. Scientists are able to recreate the same temperatures seen in the vacuum of space as well as inside the core of stars like our sun.
Our Protective Atmosphere
Back here on Earth, we have it easy. “You can have high-speed particles zipping by us outside the Earth’s atmosphere, but if you took off your spacesuit, you would feel cold because there aren’t that many particles hitting you,” says Sowell. “Here on the surface of the earth, particles aren’t moving really fast, but there are zillions of them.”
Earth’s atmosphere does an excellent job of circulating the sun’s heat through conduction, convection, and radiation. That’s why we feel temperature changes so acutely on Earth. “The particles are moving just a bit faster due to the sunlight or weather patterns,” says Sowell.
When we venture out past the safety and confines of our planet, we wear spacesuits and travel in spacecraft that help protect us from these extreme temperatures. Here, a large dose of creativity and a whole lot of insulation is critical.
The Apollo-era spacesuits, for example, had heating systems that included flexible coils and lithium batteries. Modern suits come equipped with tiny, microscopic balls of heat-reactant chemicals that helped protect astronauts from the frigid temps.
The Artemis spacesuits, which will take the next man and first woman to the moon in 2024, come equipped with a portable life support system that will help future moonwalkers regulate their temperature on the moon and beyond.
Were you to weave between galaxies in the vacuum of space without a spacesuit, the heat from your body—about 100 watts, according to Space.com—would start to radiate away from you because conduction and convection don’t work in space. This would be a slow, frigid way to go, and, eventually, you’d freeze to death. But ... it’s likely you’d asphyxiate first.
After all, space is all about extremes.
Jennifer Leman
Jennifer Leman is a science journalist and news editor at Popular Mechanics, where she writes and edits stories about science and space. A graduate of the Science Communication Program at UC Santa Cruz, her work has appeared in The Atlantic, Scientific American, Science News and Nature. Her favorite stories illuminate Earth's many wonders and hazards.
FAQs
The Weirdly Nihilistic Reason Why It's Downright Frigid. Because it's all a bunch of nothing, baby. Far outside our solar system and out past the distant reaches of our galaxy—in the vast nothingness of space—the distance between gas and dust particles grows, limiting their ability to transfer heat.
Why is it extremely cold in outer space? ›
In fact, it doesn't actually have a temperature at all. Temperature is a measurement of the speed at which particles are moving, and heat is how much energy the particles of an object have. So in a truly empty region space, there would be no particles and radiation, meaning there's also no temperature.
Would you actually feel cold in space? ›
Acute exposure to the vacuum of space: No, you won't freeze (or explode) One common misconception is that outer space is cold, but in truth, space itself has no temperature. In thermodynamic terms, temperature is a function of heat energy in a given amount of matter, and space by definition has no mass.
Why is space so cold if the sun is so hot? ›
Space is cold in the sense that it's big and empty and any object placed in space can radiate a limitless amount of energy in all directions, so if there is no sun nearby to warm it up, it will eventually lose almost all its heat and grow very cold indeed—so bring some coffee.
Why is it so cold in space and how do astronauts overcome it? ›
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.
What does space smell like? ›
Other astronauts have described it in similar yet varying ways: "burning metal," "a distinct odor of ozone, an acrid smell," "walnuts and brake pads," "gunpowder" and even "burnt almond cookie." Much like all wine connoisseurs smell something a bit different in the bottle, astronaut reports differ slightly in their " ...
How fast would you freeze in space? ›
It's also very cold in space. You'll eventually freeze solid. Depending on where you are in space, this will take 12-26 hours, but if you're close to a star, you'll be burnt to a crisp instead. Either way, your body will remain that way for a long time.
What is the coldest thing in the universe? ›
According to NASA, the Boomerang Nebula is the coldest spot in the known cosmos, with a temperature of one degree Kelvin. One degree Kelvin is 458 degrees Fahrenheit, or roughly 272 degrees Celsius. The lowest temperature recorded on Earth was 128.6 degrees Fahrenheit in Vostok, Antarctica.
How long can a human survive in space without a suit? ›
Since it takes a bit of time for these things to kill you, it's possible to make it through a very quick stint in outer space. 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.)
Why is space black? ›
In space or on the Moon there is no atmosphere to scatter light. The light from the sun travels a straight line without scattering and all the colors stay together. Looking toward the sun we thus see a brilliant white light while looking away we would see only the darkness of empty space.
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 hottest thing in the universe? ›
The hottest thing in the Universe (Supernova)
Supernovas are the hottest thing in the Universe as they reach a million degrees Celsius. These explosive events occur when a star between 8 and 40 times more massive than our Sun reaches the end of its stellar lifecycle and explodes when its core collapses.
How much do astronauts get paid? ›
How much does a Nasa Astronaut make? As of Jun 5, 2023, the average annual pay for a Nasa Astronaut in the United States is $46,585 a year.
Is there any sound in space? ›
No, you cannot hear any sounds in near-empty regions of space. Sound travels through the vibration of atoms and molecules in a medium (such as air or water). In space, where there is no air, sound has no way to travel.
How cold is deep space? ›
Far outside our solar system and out past the distant reaches of our galaxy—in the vast nothingness of space—the distance between gas and dust particles grows, limiting their ability to transfer heat. Temperatures in these vacuous regions can plummet to about -455 degrees Fahrenheit (2.7 kelvin). Are you shivering yet?
What would happen if you remove your helmet in space? ›
Within a moment, all the air will rush out of your lungs, and then you'll fall unconscious in about 45 seconds. Starved for oxygen, you'll die of suffocation in just a couple of minutes.
What does Jupiter smell like? ›
Jupiter, that giant planet of swirling gas, smells different depending on which layer you're inhaling. The lighter layers of gas smell like ammonia (think cleaning products and urine), and a little deeper, it's ammonia as well as rotten egg.
What does oxygen smell like? ›
Oxygen is a colorless, odorless gas. Liquid Oxygen has a light blue color and is odorless.
Could you survive 10 seconds in space? ›
After about one minute circulation effectively stops. The lack of oxygen to the brain renders you unconscious in less than 15 seconds, eventually killing you. "When the pressure gets very low there is just not enough oxygen.
What would happen if you were in space for 5 seconds? ›
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. But if you were rescued in the first 30 seconds, you'd probably have nothing worse than 'love bite'-type bruises over all your skin.
A small hole of ~3mm or less diameter would leak slowly enough to be survivable. Without air in the suit, an astronaut will lose consciousness in no more than about 10-15 seconds; death will follow within a minute.
Are there any bodies in space? ›
Are there any dead bodies in space? The short answer is no. There are no dead bodies in space. Most of the spaceflight-related accidents have happened on land or before reaching the line that we consider space.
How long could a human survive in space? ›
"No human can survive this — death is likely in less than two minutes," Lehnhardt said. According to NASA's bioastronautics data book, the vacuum of space would also pull air out of your lungs, causing you to suffocate within minutes.
Would blood be blue in space? ›
This leaves only high-energy blue light to be reflected from our maroon veins. So, if you cut yourself in space, your blood would be a dark-red, maroon color.
What is the oldest thing in the universe? ›
Methuselah: The oldest star in the universe. Space.
How cold is a black hole? ›
The more massive a black hole, the colder it is. Stellar black holes are very cold: they have a temperature of nearly absolute zero – which is zero Kelvin, or −273.15 degrees Celsius.
Has absolute zero ever been reached? ›
Absolute zero cannot be achieved, although it is possible to reach temperatures close to it through the use of evaporative cooling, cryocoolers, dilution refrigerators, and nuclear adiabatic demagnetization. The use of laser cooling has produced temperatures of less than a billionth of a kelvin.
Has anyone ever floated away in space? ›
The first astronaut to float away from the safety of their ship without a tether was Bruce McCandless, who reached 320 feet away from the Challenger space shuttle on February 7, 1984.
Would a body decompose in space? ›
If you do die in space, your body will not decompose in the normal way, since there is no oxygen. If you were near a source of heat, your body would mummify; if you were not, it would freeze. If your body was sealed in a space suit, it would decompose, but only for as long as the oxygen lasted.
Do you age in space? ›
Previous research has shown that spending time in space causes bone density loss, immune dysfunction, cardiovascular issues such as stiffening of arteries, and loss of skeletal muscle mass and strength in both humans and rodent models. These changes resemble aging in people age on Earth, but happen more quickly.
Why can't we see stars in the pictures of spacewalking or moonwalking astronauts? The stars aren't visible because they are too faint. The astronauts in their white spacesuits appear quite bright, so they must use short shutter speeds and large f/stops to not overexpose the pictures.
What is the real colour of space? ›
It turns out that if the universe was infinitely large and infinitely old, then we would expect the night sky to be bright from the light of all those stars. Every direction you looked in space you would be looking at a star. Yet we know from experience that space is black!
What is outside the universe? ›
The trite answer is that both space and time were created at the big bang about 14 billion years ago, so there is nothing beyond the universe. However, much of the universe exists beyond the observable universe, which is maybe about 90 billion light years across.
Why can't you yell in space? ›
A: Sound is a mecanical wave, which means that it needs substance to travel through, such as air or water. In space, there is no air, so sound has nothing to travel through. If someone were to scream in space, the sound wouldn't even leave their mouths.
Where does space end? ›
Our atmosphere is extended up to an imaginary line called the Kármán Line. The astronomers consider this line to be 100 km above sea level. It is a convention that we have agreed to follow that outer space begins from this line.
What is the heaviest thing in the universe? ›
1. Black hole in galaxy NGC 4889. This unnamed intergalactic goliath is the current heavy-weight champion. Located in the constellation Coma Berenices about 300 million light-years from Earth, it has a mass 21 billion times greater than our sun.
How hot is a hypernova? ›
The temperature in a supernova can reach 1,000,000,000 degrees Celsius. This high temperature can lead to the production of new elements which may appear in the new nebula that results after the supernova explosion.
What's the hottest thing known to man? ›
Hottest Things in The Universe
- The Flame of a Fire.
- The Melting Point of Diamond.
- The Earth's Core.
- A Lightning Bolt.
- The Sun's Core.
- Controlled Nuclear Fusion.
- The Big Bang.
Total Pay Estimate & Range
The estimated base pay is $110,120 per year. The estimated additional pay is $30,122 per year. Additional pay could include bonus, stock, commission, profit sharing or tips.
What is the lowest astronaut salary? ›
Civilian. The pay grades for civilian astronaut candidates are set by federal government pay scales and vary based on academic achievements and experience. According to NASA , civilian astronaut salaries range from $104,898 to $161,141 per year.
As of June 2, 2023 there are 10 people currently living and working in space.
Does the sun make a noise? ›
Today, we can hear the Sun's movement — all of its waves, loops and eruptions — with our own ears. This sound helps scientists study what can't be observed with the naked eye.
Is it completely Dark in space? ›
Above the Earth's atmosphere, outer space dims even further, fading to an inky pitch-black. And yet even there, space isn't absolutely black. The universe has a suffused feeble glimmer from innumerable distant stars and galaxies.
Can explosions happen in space? ›
Astronomers have observed an explosion 180 million light years away which challenges our current understanding of explosions in space, that appeared much flatter than ever thought possible.
How long is a day in space? ›
Sidereal day
Measuring a day as such is used in astronomy. A sidereal day is about 4 minutes less than a solar day of 24 hours (23 hours 56 minutes and 4.09 seconds), or 0.99726968 of a solar day of 24 hours.
Why is space infinite? ›
Because space isn't curved they will never meet or drift away from each other. A flat universe could be infinite: imagine a 2D piece of paper that stretches out forever.
How is space cold if there is no air? ›
In space, there is no air or water, so the only way to lose heat is by radiation, where your warm and wiggly atoms release energy directly into space. This is a slow process, so you'd die of oxygen deprivation long before you'd notice the cold! Read more: What Exoplanet Is Closest to Earth?
What is the coldest part of space? ›
According to the National Aeronautics and Space Administration, the coldest point in the cosmos is the Boomerang Nebula. According to NASA, the Boomerang Nebula is the coldest spot in the known cosmos, with a temperature of one degree Kelvin. One degree Kelvin is 458 degrees Fahrenheit, or roughly 272 degrees Celsius.
Is space colder than Antarctica? ›
The temperature of space is approximately -456 degrees Celsius. This translates to roughly 2.7 Kelvin. For perspective, the coldest temperature ever recorded on Earth was -138.5 degrees Celsius, or 178.45 Kelvin, in Antarctica.
Why is there no weather in space? ›
In the vacuum of space, there is no water or air, and thus there also isn't any precipitation. But there is wind — solar wind — that isn't air at all, but instead is a stream of energy and plasma, or charged particles, from the Sun. Space weather storms are invisible but still impact Earth.
That's only 3.67 degrees Fahrenheit above absolute zero. If you thought the coldest place on Earth is Antarctica, well, you just might be wrong about that. One of the coldest places on Earth is actually in Menlo Park, California — or more specifically, 30 feet (9 meters) below it.
What is hottest thing in the universe? ›
The hottest thing in the Universe (Supernova)
Supernovas are the hottest thing in the Universe as they reach a million degrees Celsius. These explosive events occur when a star between 8 and 40 times more massive than our Sun reaches the end of its stellar lifecycle and explodes when its core collapses.
What is the coldest thing in existence? ›
According to NASA, the Boomerang Nebula is the coldest spot in the known cosmos, with a temperature of one degree Kelvin. One degree Kelvin is 458 degrees Fahrenheit, or roughly 272 degrees Celsius. The lowest temperature recorded on Earth was 128.6 degrees Fahrenheit in Vostok, Antarctica.
What's the coldest city on Earth? ›
Welcome to winter in Yakutsk, the coldest city in the world. Residents of this notoriously frosty city, the capital of Russia's Sakha Republic in eastern Siberia, regularly deal with temperatures as low as minus 40 degrees Fahrenheit in the winter.
What is the coldest thing ever? ›
For comparison, the coldest recorded temperature on Earth is minus 128.6 degrees Fahrenheit in Vostok, Antarctica. A nebula is a cloud or mist of gas and dust occurring in the interstellar space, according to Britannica.
Is there a planet that rains gold? ›
A massive gas giant orbiting a star about 855 light-years from Earth, WASP-121b may have metal clouds and rain made of liquid gems, according to new research. A study showing how water atmospherically cycles between the planet's two sides published Monday in the journal Nature Astronomy.
Does wind exist in space? ›
Did you know that there are storms always occurring in space? Not rain or snow, but winds and magnetic waves that move through space! This is known as space weather.
What is the most powerful thing in the universe? ›
These explosions generate beams of high-energy radiation, called gamma-ray bursts (GRBs), which are considered by astronomers to be the most powerful thing in the universe.
Is anywhere on Earth getting colder? ›
It's a strange tale of two hemispheres. New research shows the Pacific hemisphere is losing heat faster than the African hemisphere. The heat is from Earth's molten interior, which causes continental drift.
