Planet 9?! even less evidence (Introduction)

by David Turell , Monday, February 22, 2021, 19:26 (1369 days ago) @ David Turell

Another article:

https://www.nature.com/articles/d41586-021-00456-7?utm_source=Nature+Briefing&utm_c...

"The presence of Planet Nine was proposed1 in 2016, when astronomers Mike Brown and Konstantin Batygin at the California Institute of Technology in Pasadena observed that the orbits of six trans-Neptunian objects (TNOs) — part of the Kuiper belt, a collection of small bodies orbiting the Sun beyond Neptune — seemed to be clustered together.

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"To investigate whether the objects were truly clustered, Napier’s team built a computer model simulating ten billion evenly distributed ETNOs in the outer Solar System, and then calculated the chances that observing a small sample of these would produce results matching existing observations. The team concluded that there is no reason to think that ETNOs are not uniformly distributed, and that it’s possible that observed objects only seem to be clustered because of selection bias. “That doesn’t mean that Planet Nine isn’t there, but it’s not necessary to explain the data,” says Napier. “You could fit this data with clustered ETNOs as well — but if you hear hoofbeats, you should think horses, not zebras.”

"Brown, however, disagrees. “I plotted all their data on top of our old paper, and you just simply look at it, and it’s very clustered,” he says. “There’s actually strong evidence for Planet Nine in their data.” He points out that the paper does not include the six TNOs that he and Batygin used in their original research. He also argues that the researchers are “mixing dirt in with their ice cream”, because their analysis considers objects whose orbits might be affected by their proximity to Neptune.

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"Lawler says new surveys of the outer Solar System are needed to look for any other evidence of clustering. One of the best chances will come from the Vera C. Rubin Observatory in Chile, which will begin a ten-year survey of the sky in 2022.

“'They’re going to detect thousands more Kuiper belt objects,” says Lawler. “I think we’ve really done all that we can with the data we currently have.”

"Even if it turns out Planet Nine isn’t there, Lawler says, it has sparked a lot of useful interest in the outer Solar System from astronomers. “The theory of Planet Nine has been fantastic for the study of the Kuiper belt,” she says."

Comment: Debates like this advance our general knowledge. More research is awaited.