On a sunny day with a blue sky filled with clouds, try stepping out into your garden or go for a walk. Now look at the clouds above. Use your imagination and try to make out as many interesting patterns or shapes that you can see — like a sky pictionary! Strange-shaped clouds of gas also exist beyond our planet, farther out in space. 

Using data from the James Clerk Maxwell Telescope and NAOJ’s Nobeyama 45-m Radio Telescope, a team of researchers from the Keio University in Japan identified an unusual cloud of gas. The cloud is nicknamed “Tadpole” due to its curved shape. Tadpole is located at about 27,000 light-years away from Earth, in the Sagittarius constellation.

The research team suspects a massive yet small object behind the curved shape of the Tadpole. This is because the cloud appears to be stretched as if it were being pulled by something massive while moving around it, due to gravity. Just like when you drop a rock into a pantyhose. Researchers then began to look for bright, massive objects at the centre of Tadpole’s orbit, like the Sun at the centre of our Solar System. But, very much to their surprise, they could not find any!

Astronomers suggest that the Tadpole might be orbiting a dark object, most likely a black hole 100,000 times more massive than the Sun. The only way to see this dark object is by observing how it behaves with other nearby bright objects. Astronomers are yet to figure out how many black holes and of what mass they should be looking at.

The team is optimistic as they plan to use ALMA (Atacama Large Millimeter/submillimeter Array) to look for weak signs of a black hole, or another object, at the centre of the Tadpole’s orbit. This way, they hope to explain what is responsible for the Tadpole’s peculiar shape.

Image: Artist’s Impression of the “Tadpole” Molecular Cloud and the black hole at the gravitational center of its orbit. (Credit: Keio University)