I listened to a recent Cool Worlds Lab podcast where Professor David Kipping interviewed Professor Malena Rice from Yale University’s Department of Astronomy. The episode, titled Planet Nine, Oumuamua, Misaligned Exoplanets, covered a good range of topics, as the title suggests.
Of greatest interest to me was the continued search for a ninth planet in our solar system (sorry, Pluto). Professor Rice was noncommittal on the likelihood of such a planet, but she is hoping NASA’s Transiting Exoplanet Survey Satellite (TESS) can help to bring more light to the topic.
She discussed how this ninth planet is estimated to be a sub-Neptune sized planet, which appears to be common in many other solar systems we have observed. Planet Nine is estimated to be a gas giant about 5-10 times the mass of Earth yet smaller than Neptune lying 300-800 astronomical units from the Sun (or about 10 times more distant that Pluto).
Professor Rice noted that it is pretty amazing that we can discover distant galaxies but not potential planets in our backyard. She attributes this difficulty to the lack of light on such a planet.
The podcast episode dives deep in this topic, and then continues into other fascinating topics such as visitors to our solar system and strange solar systems elsewhere. It is a lot to take in, but well worth the time even if you need to play it more than once.
Note: Of course, it may not be a planet at all. One theory is that it is a black hole at the edge of our solar system. I would like to hear that podcast as well.
Our Awesome Universe 