Boötes Void: One of the Largest Voids in the Observable Universe

The universe is... gigantic. Experts assign it a diameter (if we can speak in those terms) of about 93 billion light-years, and it continues to expand. But the universe is also home to incredible superstructures, and disturbing voids. One of them is the so-called Boötes Void. With an estimated diameter of 250 million light-years, the Boötes Void only holds about 60 galaxies, so from a practical point of view... it has nothing.

The Milky Way is far from being alone. Andromeda is heading here at full speed, and will need another 4.5 billion years to arrive. The latest evolutionary models suggest that the Large Magellanic Cloud will meet us much sooner, about 2.4 billion years.

The Local Group has more than 50 galaxies, and the Laniakea supercluster defined in 2014 is home to some 100,000 galaxies. Of course, the universe contains other superclusters, but if there is anything as impressive as them, it is the voids.

The Boötes Void: Location and Shape

One of the ones that has gone through the media with some frequency is the so-called Boötes Void. Located near the constellation Boötes (or the Herdsman), anyone who decides to 'locate' it should point at right ascension 14 h 20 m, and a declination of 26 degrees.

One of the first things that catches the eye about the void is that it has a much more spherical shape than expected. Current data give it a diameter of 250 million light-years, although other sources raise that number to 330 million.

Discovery and Galaxies

After its discovery in 1981, scientists were only able to detect eight galaxies inside, but with a series of observations using more powerful instruments, the total number of galaxies rose to 60.

The Emptiest Place?

A sphere of 250 million light-years for 60 galaxies, when the average indicates it should hold about ten thousand, and the Milky Way has 25 galaxies in its neighborhood of three million light-years.

Is it "the emptiest place in the universe"? We don't know for sure because there is always something new to discover, but so far, the title belongs to it. The void equals 0.27 percent of the observable universe, so it is a dwarf compared to the rest of absolute creation, however, that doesn't take away its disturbing nature.

Theories and Explanations

Another comparison? Let's see: If we place the Milky Way at the center of the void, it would not have been possible for humanity to discover other galaxies until the 1960s. But that's not all: The very formation of the void challenges experts.

Some believe it breaks the Big Bang theory and the initial uniformity of the cosmos. Others say it's a 'bubble' of dark energy. And obviously, the alien factor couldn't be missing, with a Type III supercivilization on the Kardashev scale expanding through the void, absorbing the energy of nearby galaxies.

Now, what is most likely? That it's a simple union of multiple voids. But never say never! The universe has left us with our mouths open before, and it will do so again.