What lies outside of our Milky Way galaxy? The answer is millions of other galaxies. But what lies in the space between these galaxies is something more. In the space between each of these galaxy is something called the intergalactic medium, an extremely hot gas that is practically emitting a form of X-rays.

Due to this X-ray effect, the environments temperature rises, allowing for its temperature to rise up over several millions of degrees kelvin.

The Intergalactic Medium, Beyond the Milky Way

Early on in astronomies history, it was theorised that between the galaxies there was a large amount of gas of some sort, inhabiting the surrounding areas. Across the years, they slowly whittled down the different possible gasses, until they came to the one plausible answer. An exceedingly hot type of plasma.

In physics, plasma is both a conductor of electricity and an electrical medium. The number of particles it contains is very similar, both positively and negatively charged particles ending up with approximately the same number of particles as each other.

The intergalactic medium (intergalactic space) is not between every empty part of space. It is one of the rarest things in the universe, and is only detectable, a problem, if there are large clusters of it in a small (comparatively) area.

Intergalactic space lies hundreds of millions of light-years away from our current position and is surrounded by total darkness.

Intergalactic space is close to devoid of all matter, making it very close to a vacuum. The majority of the matter it contains is ionised gas, fore the most part heated hydrogen. In intergalactic space, the density of ionised hydrogen is 10 times less than it would be in any other intergalactic environment. Its density in a formula is 1 atom of Hydrogen to 1 cubic decimeter.

Hydrogen isn’t the only element to be found in intergalactic space. Other common elements found including Carbon, Oxygen and Silicon.

The Intergalactic Medium, Beyond the Milky Way
The Intergalactic Medium, Beyond the Milky Way

Part of the gas found in the intergalactic space is concentrated in different clouds. Not all of these clouds are the same either, they differ by a lot in categories such as density and temperature.

The strange part is that the chemical composition is varied. It may contain elements such as Hydrogen, Helium, Carbon, Nitrogen, Oxygen, Sulfur and a diverse range of metals.

Not everything in the intergalactic medium is gas, there are also larger objects that can be found in this part of space. Quite recently they have managed to spot stars, adding to the trillions of stars able to be spotted in the observable universe.

So far we have managed to detect over 650 of these unusual stars, hanging out in our own galaxy, the Milky Way.

This discovery was actually just a coincidence, as nothing in intergalactic space emits any light, leaving these ‘rogue’ stars to stand out.

In the 1960’s they accidentally spotted a quasar, starting this search for outcast stars in unusual parts of space. While investigating this quasar, scientists quickly noted that there were certain parts of the light this star was giving off were missing.

It was later speculated that something had practically absorbed these missing parts before it reached the astronomer’s telescope. They later discovered that the thing that had been absorbing the quasars sunlight was, in fact, the gas of the intergalactic medium (IGM).

After this first astounding discovery, they later found out that there were heavier elements in the IGM.

Intergalactic Medium
Intergalactic Medium - Intergalactic Space

Although at first glance the IGM appears empty, it’s dimensions and size are so incredibly large that there is more fairly distributed matter around it than the combined amount of matter throughout each galaxy in the observable universe.

If you wish to know how long we would survive if we were in total darkness click here.


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