How Cold Is It in Space? What’s the Coldest Space in Solar System?

Space has a very low temperature in comparison to Earth. It is very, very cold in contrast to our planet.

How Cold Is It in Space?

The universe is quite chilly. The universe's temperature is 2.7 Kelvins, or minus 454.81 degrees Fahrenheit, or 270.45 degrees Celsius, which means it is only slightly warmer than absolute zero, the temperature at which molecular motion ceases, Live Science reported.

Temperatures in these barren areas can drop as low as -455 degrees Fahrenheit (2.7 Kelvin), according to Popular Mechanics.

Knowing the temperature of space is all about motion and velocity for physicists. James Sowell, an astronomer at the Georgia Institute of Technology, said when they discuss a room's temperature, that is not how a scientist would describe it. To define the speeds of all the particles in a given volume, we would use the term "heat."

Stars like our Sun generate the majority, if not the entirety, of the heat in the universe. Temperatures inside the Sun, where nuclear fusion occurs, can reach 15 million Kelvin. (They only get up to around 5,800 Kelvin on the surface.)

The heat emitted from the Sun and other stars is known as solar radiation, and it travels across space as infrared waves of energy. Everything not directly visible from the Sun remains cool since these solar rays only heat the particles in their path. Really cool, I guess.

Even Mercury, the Sun's nearest neighbor, has a surface temperature dip at night of roughly 95 Kelvin. About 40 Kelvin is the maximum temperature on Pluto's surface.

Coincidentally, the solar system's lowest temperature was measured far closer to Earth. According to New Scientist, when temperatures were monitored in a deep crater on our moon in 2009, it was discovered that they plunged to roughly 33 Kelvin.

That is extremely cold- -400 degrees Fahrenheit.

ALSO READ: How Fast Does Each Planet in the Solar System Spin? Watch These Planetary Animations To Find the Answer

What Is the Coldest Place in the Solar System?

However, this temperature varies across the solar system. Though it is not empty, so-called "empty" space is much colder than objects like planets, moons, and asteroids because there is (practically) nothing there to absorb solar radiation.

What region of the solar system is the coldest, excluding ordinary "empty" space? And how does it measure up to Earth's temperatures?

The lunar south pole's "shadowed craters" may be the coldest location in the solar system, according to data released in 2009 by the Lunar Reconnaissance Orbiter, a NASA robotic spacecraft created to aid scientists in better understanding lunar conditions, Live Science reported.

Later, planetary scientists at the University of Arizona, Patrick O'Brien and Shane Byrne, who are Ph.D. students, supported this notion. According to O'Brien and Byrne, the moon craters that are "doubly shadowed" could be "the coldest places in the solar system," according to their discussion at the 2022 Lunar and Planetary Science Conference.

O'Brien and Byrne said a crater could be doubly shadowed if it is shielded from direct solar illumination and secondary heating sources like solar radiation reflected off nearby illuminated areas and thermal radiation emitted from warm surfaces.

They are so frigid because "doubly shadowed" craters "have high enough rims and sunlight never reaches them, Don Pollacco, a professor of astronomy at the University of Warwick in the United Kingdom, added.

According to O'Brien and Byrne's research, these "permanently shadowed regions" have been "shielded" from solar illumination for billions of years, meaning that their craters may hold "micro-cold traps" that contain "not only water ice but also more volatile compounds and elements," like carbon dioxide, carbon monoxide, dinitrogen, and argon.

These craters could be even colder than the predicted temperature of 25 kelvin (minus 414.67 F or 248.15 C) given by O'Brien and Byrne.