Did you know that in trans-ocean flights, where the altitude of the aircraft is 12,000 km above the surface, the outside temperature can reach -50 ºC? Also, as we progress through the atmosphere and approach space, the temp coming down Suddenly, it pushes the thermometer beyond the usual limits of hot and cold.
In fact, the average temperature in the universe is estimated to be approx -266 ºC, i.e., the value closest to absolute zero. But what are these minimum temperatures in space? Shouldn't it be hot because of the light and radiation emitted by the many stars that make it up?
Well, there are many different factors that explain this unique temperature and they range Cosmic background radiation Until then Absence of heat transfer medium. In fact, one of the factors that most affect this phenomenon is the absence of a material medium that provides the molecules that conduct or transfer heat from one place to another: Thermal insulation. Without air or gas to act as a conductor, the particles are isolated and the distances between them are too wide to achieve significant heat transfer.
Radiation and the atmosphere
In particular, the Radiation It is the main form of heat transfer in space. Unlike other methods such as conduction or convection, which require a material medium for its propagation, thermal radiation can occur in a vacuum. Indeed, in space it is omnipresent and manifests itself in various forms, the most famous of all Electromagnetic radiation. It appears in the form of a wide variety of wavelengths, from powerful gamma rays to soft radio waves, and of all of them, visible light is only a small fraction.
The electromagnetic spectrum highlights the visible light region.
This type of radiation originates from stored energy itself in atoms. For example, stars are enormous sources of radiation, they emit light and heat through various nuclear processes in their cores, and as it travels through space, it encounters various obstacles such as dust, gases, and other bodies. Now, these are only a minimal part, because if anything is mentioned, it is empty. So, in reality they do not have a large number of particles that can collide, excite and transfer thermal energy. Another consequence of this fact is that thermal radiation will be coupled with very cold temperatures because there will be no material to moderate it.
No, the vacuum isn't really empty
On the other hand, the No atmosphere It plays an important role at this stage. While on Earth the atmosphere acts as a filter limiting the amount of solar radiation reaching the surface, there are no such barriers in space. Since there are no molecules, no Atmospheric pressure It retains heat, thus contributing to the rapid spread of radiation, contributing to lower temperatures.
Cosmic microwave background radiation
Now, the Cosmic microwave background temperature (CMB) is a core region. This is a cosmic phenomenon known as background radiation, identified with the persistent echo of the Big Bang explosion, the event that marked the birth of our universe. The temperature of this radiation is about 2.7 degrees Kelvin, ie approx -270.45 ºC. And, as you might have guessed, it's flooding space in all directions and radiation that originated in the first moments of the universe, about 380,000 years after the Big Bang.
Is the universe doomed to evaporate?
In those early years, the universe was like a dense soup of many charged particles emitting radiation in the form of photons. However, cosmically Expanded and cooled, that radiation was released, creating CMP. Since then, the photons that make it up travel through space, creating a kind of “Fingerprint”. This radiation interacts with cosmic objects, affecting their temperature and contributing to the warm color of the universe.
