Giant Hole in the Universe: What is the Boötes Vacuum?

An artist’s impression of a void in space. Image credit: Golubovy / shutterstock.com

Another week, another viral post that skews the space. This time it’s Barnard 68, who – if the internet is to be believed (which it isn’t) – “an empty void in space so big that if you traveled through it you wouldn’t bump into anything for 752,536,988 years”.

While it’s smart not to limit speed (hey, it’s technically correct that if you travel a few meters in a year, you probably won’t hit anything in 752,536.988 years), that’s definitely not the case.

What you see above is a real image of the dark nebula Barnard 68, which is too close (400 light-years away) to see anything between it and the Sun, taken by the European Southern Observatory (ESO) Very Large Telescope in March 1999. However, it is Totally full of stars, even if you can’t see them when photographing the area with visible light, thanks to the molecular cloud. As ESO explains, “At these wavelengths, the small cloud is completely opaque due to the mysterious effect of dust particles within it.”

If you shoot it in the infrared, here come the stars.

Photo of Bernard 68. The center - where you see the void in visible light - is full of infrared stars.
Composite image of Bernard 68. Center, colored red, shows the imaged region in infrared light. Image credit: ESO

As IFLScience’s Francesca Benson has expressed, saying that this is a void in space because you can’t see beyond the dark nebula is like claiming that the sun doesn’t exist because the clouds are.

But lovers of strange large voids in space, do not despair, because there are a lot of mysteries in the infinite space of the universe.

The Great Nothingness: A Real Void in Space

The Boötes void, often referred to as the Great Nothing or Great Void, is an actual expanse of space with fewer galaxies than you might expect. With a diameter of 250 to 330 million light-years, it is one of the largest voids that we know of. To put that in context, that’s about 2% of the diameter of the entire observable universe.

The void was first discovered in 1981, in the context of a redshift survey of galaxies. The astronomers published their findings in a paper titled “Vacuum of MFC in Boötes?” , they note that one plausible explanation for the data they collected is that the region is “almost devoid of galaxies.”

Slowly, astronomers began to find galaxies in the region, and by 1997 about 60 galaxies had been confirmed in the None Great in a region that should contain nearly 2,000 galaxies (if space is that uniform). While there isn’t much about the void that suggests our ideas about the formation of galaxies are incorrect – one possible explanation is that they formed from the merging of smaller voids – it’s still a strange thought experiment to visualize how someone inside the void should see the universe.

As astronomer Greg Aldring said: “If the Milky Way was in the middle of the Boötes void, we wouldn’t know about other galaxies until the 1960s.”

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