We will start by explaining the physical phenomenon on which the temperature that something can have depends.
When the particles of an object move a lot, they generate heat, and the entity has a higher temperature. When particles move less, there is less heat, and the thing is colder. We can imagine a point where it is so cold that the atoms and their subatomic particles do not move. This point is called absolute zero (and in degrees, it represents −273.15 °C). At this temperature, the internal energy level is the lowest possible in this universe. The particles, according to classical mechanics, lack any movement or vibration.
Can an Absolute Zero Be Reached?
However, we have never been able to demonstrate this theory because we have never reached absolute zero. But we have been close, we have come very close. A piece of rhodium has been cooled to one ten billionth above absolute zero.
However, according to quantum mechanics, absolute zero must have a residual energy, the so-called zero point energy, in order to fulfill Heisenberg’s uncertainty principle. Fine, but we’re not going to stop here.
According to the third law of thermodynamics then, absolute zero is therefore an unattainable theoretical limit.
What Is the Coldest Place in Our Solar System?
All right, having said that, do you know which is the coldest place in the solar system? Pluto already lost its coldness status years ago, and its successor is neither Uranus or Neptune, but a little rock just around the corner.
Yes, you guess right. It is the moon. Incredible, but true. It was confirmed as hosting the coldest place in the solar system (that we know of), in 2009. Inside its deepest craters, where sunlight cannot access, a temperature of -248 degrees Celsius (-415 degrees Fahrenheit) was measured by NASA’s Lunar Reconnaissance Orbiter.
What Is the Coldest Place in the Universe?
But the coldest place in the known universe is The Boomerang Nebula, which is about 5,000 light years distant from Earth. Its temperature in some places is a staggering -272 ºC. Only one degree warmer than the lowest limit for all temperatures, absolute zero.
Well, let’s recall once again why it is not possible to cool an object infinitely. Temperature is a measure of how fast the particles that make up the object move. When we cool it down, its particles move more and more slowly, until they stop. That’s absolute zero. As the particles cannot move slower than “not at all”, it is not possible to cool it further.
Unless you have infinite time and resources, you cannot get to absolute zero temperature. Thus, reaching absolute zero is an impossible task, since there is always at least some type of vibration.
Now we know that there is a lower limit of temperature. Put another way, things can get very cold, but only up to a point – absolute zero. But, is there a limit on the other side?
Can Infinite Temperature Be Reached?
When a material is very hot, its particles have a large amount of thermal energy, and they move and vibrate a lot. That is, the opposite of when they are cold.
Solids melt and liquids vaporize, because their thermal energy exceeds the forces that unite atoms or molecules. At even higher temperatures, atoms dissociate into electrons and ion plasma (another state of matter). The more energy is injected into a system, the more its temperature rises But, high temperatures also have their limits.
The fundamental temperature on any scale is 100º, which marks the boiling point of water (but as we can suppose, this is very little).
What Is the Hottest Planet in the Solar System?
The hottest planet in the solar system is not Mercury as one might expect being the closest to the sun, but Venus. On this planet average temperatures reach 471 °C (880 °F). This record is due to its thick atmosphere that retains heat.
In 2017, a planet was discovered that is estimated to reach 4,300 degrees Celsius (7,770 degrees Fahrenheit). The funny thing is that the distance that separates it from its star is 650 times the distance that separates us from the Sun. Even so, it still reaches that staggering temperature. The explanation is that it always faces its star. Let’s move on to something substantially hotter than that.
Extreme Temperatures of Stars
A star like our sun has an average temperature of about 5,500 degrees Celsius (10,000 Fahrenheit) on its surface. At its core it can reach 15 million degrees (27,000 Fahrenheit).
Obviously, the larger the size of a star, the hotter the plasma inside it will be. There are stars larger than the sun, which can reach temperatures of over 200 million degrees inside. But in reality, that is also nothing when compared to other starry phenomena.
For example, when a very large star runs out of fuel but does not have enough mass to form a black hole. The supernova with which it ends its life leaves behind a neutron star. At the beginning of their life, these stars can reach temperatures of up to 1 trillion degrees. Although they cool down very quickly, and within seconds their temperature drops to a “refreshing” 100 million degrees.
What Is the Highest Temperature Produced Artificially?
That trillion degrees reached momentarily probably seem outrageous to you. But when the Large Hadron Collider smashes lead ions together, the collisions regularly reach temperatures of 5.5 trillion degrees Celsius. But as incredible as it may seem, nature has outdone us once again.
In 2016 Russian scientists measured the temperature of a quasar called 3C 273 located more than 2 billion light-years from Earth. The result they got defies logic. They revealed that it was hotter than 10 billion degrees!
Is There an Absolute Hot?
Okay, so are quasars the hottest thing you can find in the universe? Can a maximum temperature be reached?
Classical mechanics do not predict any upper temperature limit. In fact, many textbooks gleefully state that the temperature can rise to infinity. However, according to modern physics, it is not possible to reach an arbitrarily high temperature.
Because if there is a limit to the total energy that exists in the universe, there is also a maximum possible temperature.
The highest temperature reached in the history of our universe is the so-called Planck Temperature. Some scientists believe that it occurred just after the Big Bang. This temperature would be equivalent to 1,416 × 10 raised to thirty-two. At these temperatures the energy of the particles is so high that it is not known how matter would behave. From this point, things get pretty confusing for today’s physics.
To give us an idea of this huge figure, the core of our sun would be 10 trillion times colder. So, the maximum temperature limit value is the Planck temperature. It is the highest possible temperature in our universe, and it is the opposite of absolute zero.
