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.
The upshot of this is a very cold region of space and it's best expressed by recapping the lowest limit of the thermodynamic temperature scale: absolute zero. On the Celsius scale this is –273.15 degrees and on the Fahrenheit scale it is –459.67 degrees.
Using laser beams configured in a unique manner, a team at the National Institute of Standards and Technology in Boulder, Colorado, USA, cooled a miniscule aluminium drum to a staggering 360 microkelvin (-273.14964°C, which is near Absolute Zero or -273.15°C), or 10,000 times colder than the vacuum of space!
An underground superconducting particle accelerator at the SLAC National Accelerator Laboratory has been cooled down to a mind-boggling minus 456 degrees Fahrenheit (minus 271 degrees Celsius or 2 kelvin). That's just a few degrees above the coldest possible temperature in the universe, absolute zero.
A supernova is the hottest thing in the universe. The temperatures at the core during an explosion skyrocket up to 6000X the temperature of the sun's core.
Stellar black holes are very cold: they have a temperature of nearly absolute zero – which is zero Kelvin, or −273.15 degrees Celsius.
It is commonly held that the maximum temperature at which humans can survive is 108.14-degree Fahrenheit or 42.3-degree Celsius. A higher temperature may denature proteins and cause irreparable damage to brain.
Some parts of space are hot! Gas between stars, as well as the solar wind, both seem to be what we call "empty space," yet they can be more than a thousand degrees, even millions of degrees. However, there's also what's known as the cosmic background temperature, which is minus 455 degrees Fahrenheit.
If atoms come to a complete stop, they are at absolute zero. Space is just above that, at an average temperature of 2.7 Kelvin (about minus 455 degrees Fahrenheit).
Originating when the universe was much denser and hotter than it is now, the starting temperature of the radiation that makes up the CMB is estimated to have been around 3,000 K (5,000° F/2,726⁰C). As the universe continues to expand, that means space is colder now than it's ever been and it's getting colder.
And the answer: lightning. According to NASA, lightning is four times hotter than the surface of the sun. The air around a stroke of lightning can peak at 50,000 degrees Fahrenheit, while the surface of the sun is around 11,000 degrees. Meanwhile, magma can reach temperatures near 2,100 degrees.
Temperature in the inner core is about 5,200° Celsius (9,392° Fahrenheit). The pressure is nearly 3.6 million atmosphere (atm). The temperature of the inner core is far above the melting point of iron. However, unlike the outer core, the inner core is not liquid or even molten.
But what of the average temperature of space away from the Earth? Believe it or not, astronomers actually know this value quite well: an extreme -270.42 degrees (2.73 degrees above absolute zero).
Therapeutic hypothermia was introduced: The body is cooled down to induce hypothermia to protect patients during open heart surgery as well as victims of strokes, seizures and liver failure. Still, 56.7 degrees is the coldest anyone has ever been and survived.
At a core temperature of 29.5 degrees Celsius most people would die, as the heart beats only two to three times per minute, and the pulse and respiration are barely measurable. Once the temperature is below 20°C, death is almost certain.
In the vast gulf between stars and galaxies, the temperature of gaseous matter routinely drops to 3 degrees K, or 454 degrees below zero Fahrenheit. It's about to get even colder.
Astronaut Thomas Jones said it "carries a distinct odor of ozone, a faint acrid smell…a little like gunpowder, sulfurous." Tony Antonelli, another space-walker, said space "definitely has a smell that's different than anything else." A gentleman named Don Pettit was a bit more verbose on the topic: "Each time, when I ...
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.
There's a limit to how much of the universe we can see. The observable universe is finite in that it hasn't existed forever. It extends 46 billion light years in every direction from us. (While our universe is 13.8 billion years old, the observable universe reaches further since the universe is expanding).
Astronauts may have no trouble moving heavy objects in the weightlessness of space, but that doesn't mean that the experience isn't hard on their backs. Astronauts on long-duration spaceflights routinely report back pain, both during and after the flight.
Fires can't start in space itself because there is no oxygen – or indeed anything else – in a vacuum.
Taking the Moon's Temperature
Daytime temperatures near the lunar equator reach a boiling 250 degrees Fahrenheit (120° C, 400 K), while nighttime temperatures get to a chilly -208 degrees Fahrenheit (-130° C, 140 K).
In general, temperatures above 90 degrees Fahrenheit can quickly get extra risky, so try to avoid going outdoors if it's anything hotter than that.
More than 300 people live year-round in Death Valley, one of the hottest places on Earth. Here's what it's like.
Precautions. Research has shown that when the temperature gets to 35C, accompanied by high humidity, health is put at danger. Once 40C is reached, it can be dangerous even with low humidity levels. Suffice to say at 50C, the risk is even higher.