Another search for Planet 9 comes up empty

A ninth planet beyond Neptune was not found in a new survey of the solar system's outer reaches.

Astronomers used a telescope in Chile to look for Planet 9 in the sky. The scientists behind the research acknowledged that more sensitive searches would make the result more definitive.

The Harvard-Smithsonian Center for Astrophysics, a participating institution in the research, found about 3,500 tentative candidate sources, but none could be confirmed.

Does Planet Nine exist?

In the scanned area of the sky, scientists were able to exclude a world with the supposed properties of Planet 9 and the results were consistent with other null searches for Planet 9.

It is the latest in a string of searches that have failed since a team of astronomer argued that a large world might explain a strange large gravity source in deep solar space. The existence of a large unseen world far out in the solar system was suggested by the six trans-Neptunian objects found by the California Institute of Technology.

The team behind the research acknowledged how difficult it would be to find such a planet. Planet 9 is thought to be between the size of Earth and the distance from the sun. The Earth and sun are on average 93 million miles apart.

A small planet so far away would be hard to find in an optical search because the world wouldn't see a lot of sunlight. The team noted that it was difficult to find Planet 9 in past attempts.

Cosmic microwave background radiation, also known as the signature of the Big bang, is what the new telescope looks for. The team stated that the telescope for Planet 9 was suitable for this type of search because of its high resolution and sensitivity.

Over the course of six years, the astronomer looked at 87% of the sky accessible from the southern hemisphere. The team acknowledged in the statement that more advanced surveys may provide more information.

The researchers are excited to see the results of the project that is based in Chile and will spend most of its time in the microwave background.

A study based on the research was published in the Astrophysical Journal.

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