More from the folks behind the paper: http://www.findplanetnine.com/
Have to recommend this, especially Konstantin Batygins piece has great narrative.
Caltech Researchers Find Evidence of a Planet Beyond Pluto
111–120 of 159 posts
Re: Caltech Researchers Find Evidence of a Planet Beyond Pluto
#112Why wouldn't their calculations be able to suggest possible locations for the planet?
They do, and at the end of the press release it says that Brown has begun an observing campaign to find the planet. Unfortunately detecting these very distant objects is very difficult. The light we see from them is reflected light from the Sun, so their apparent brightness goes as 1/r^4, not 1/r^2 like most objects. And because they are so close, there is a strong parallax from the motion of the Earth. THe consequen…
In a previous life, back in the pre-CCD days I worked at an observatory searching for new asteroids. Used to be the way it was done you would point a telescope at the part of the sky directly opposite the sun (min r^4 so best chance of detection), expose a photographic plate, and repeat a few hours later. Develop the plates, mount them in a blink comparator [1] and scan manually, flipping back and forth between the plates for ~3 hours to look for anything that moved. Exclude false positives like plate blemishes (aka Eastman-Kodak Objects) or dust grains. If you see something, and it is smeared indicating motion during the exposure, mark it as a possible candidate. Revisit the same patch of sky the next night, search again. Use the datapoints to extrapolate forward, check again a couple of weeks later. If you haven't lost it (which frequently happened if it was at the limit of visibility), extrapolate back to the previous opposition (~4 years for a main belt asteroid) and search the archives for a match. If you get one, then extrapolate further back and check all previous oppositions. If you get a match on three separate oppositions, congratulations, you have a discovery.
Vastly different now - a single observation can net large numbers of asteroids and sensitivity is so much better. Still the search for this potential new planet is definitely going to be daunting given the distance.
Re: Caltech Researchers Find Evidence of a Planet Beyond Pluto
#113> Batygin and Brown inferred its presence from the peculiar clustering of six previously known objects that orbit beyond Neptune. This raised a big red flag in my mind. This must produce a literally astronomical multiple comparisons problem. Yes they reported sigma = 3.8, but if they didn't do their multiple comparisons correction right (which I am in no position to determine), they're basically reading tea leaves. I…
So I might not have a great enough understanding but isn't 3.8 sigma not high for this kind of announcement (with the current title)? if someone wants to report finding a planet in the solar system ten times the size of Earth wouldn't they do so at more than @3.8 sigma. In particular, the prior is quite low because it would affect a bunch of other astronomical calculations, wouldn't it? So you would want the confiden…
No, this is just about right. The evidence they have points sharply to there being a ninth planet. Now they're saying "here's where it might be, we need help finding it!"
Once someone has a photo and an orbit, that'll be the >>3.8sigma you want, but I don't think anyone is saying anything like that yet. What they're saying is "dedicating 5 years of the pinnacle of your planetary astronomy career to looking for this thing is probably not a waste." They directly compare this to the theoretical prediction of Neptune, so I think the authors have this same interpretation of what they are doing.
Re: Caltech Researchers Find Evidence of a Planet Beyond Pluto
#114Why wouldn't their calculations be able to suggest possible locations for the planet?
They do, and at the end of the press release it says that Brown has begun an observing campaign to find the planet. Unfortunately detecting these very distant objects is very difficult. The light we see from them is reflected light from the Sun, so their apparent brightness goes as 1/r^4, not 1/r^2 like most objects. And because they are so close, there is a strong parallax from the motion of the Earth. THe consequen…
That's why you use Goldstone and Arecibo, and bounce your signal!
Re: Caltech Researchers Find Evidence of a Planet Beyond Pluto
#115Maybe it's a Death Star?
Re: Caltech Researchers Find Evidence of a Planet Beyond Pluto
#116No one's mentioned Tyche yet? https://en.wikipedia.org/wiki/Tyche_%28hypothetical_planet%2... In searching for Tyche, the WISE missions ruled out the possibility of anything larger than Saturn (95x the mass of Earth) out to about 10000 AU and anything larger than Jupiter (317x the mass of Earth) out to about 26000 AU. WISE was able to detect objects the size of Neptune (17x the mass of Earth) out to about 700 AU, so…
For comparison:
* the aphelion of Sedna, the most distant dwarf planet of our Solar system is at 937 AU from the Sun [1],
* distance between Proxima Centauri and the binary Alpha Centauri is 15,000 ± 700 AU [2],
* one light year is 63,241.1 AU,
* distance to the nearest star (Proxima Centauri [2]) is 4.2421 ly = 268,274.973 AU,
[1] https://en.wikipedia.org/wiki/90377_Sedna
[2] https://en.wikipedia.org/wiki/Proxima_Centauri
EDIT: formatting and added Proxima-Alpha Centauri distance.
Re: Caltech Researchers Find Evidence of a Planet Beyond Pluto
#117Did anyone else notice that the rendering of the orbits in the article looks strikingly similar to Kerbal Space Program's orbit UI?
Or is it perhaps the other way around. Did Kerbel use the same UI as a popular rendering program used by astronomers.
I want, by the way, an interactive map of the solar system, complete with known spacecraft, with the same UI as the KSP map. I've never met anything quite as good at visualising planetary systems.
I haven't found one.
Re: Caltech Researchers Find Evidence of a Planet Beyond Pluto
#118I don't seem to have a grasp of our visibility of our solar system. We can see a number of the planets with the naked eye, a number of the moons with binoculars and a few hundred $/£/€/.. telescope. Yet even with these great big radio telescopes, antenna arrays, Hubble, etc, we seem to be quite unaware of what's in our neighbourhood. Anyone have figures of how much we've surveyed?
Just to offer some context in layman's terms: 1. These objects are very, very far from the sun (and Earth). 2. These objects are planet(oids), not stars, so don't produce their own light. 3. They are probably very cold and don't emit much in the IR spectrum. 4. They may have low albedo, coupled with their distance from the sun, means they reflect very little visible light. 5. Space is huge. Trying to spot a tiny, dar…
Like the parent, this seems odd that just now in 2016 we find there might be another planet in our own solar system when planets are being discovered in other solar systems and galaxies all the time.
There's this from the article:
"For the first time in over 150 years, there is solid evidence that the solar system's planetary census is incomplete."
It's our _own_ solar system and we just now found this massive thing?
Re: Caltech Researchers Find Evidence of a Planet Beyond Pluto
#119Earlier quoted context omitted.
Just to offer some context in layman's terms: 1. These objects are very, very far from the sun (and Earth). 2. These objects are planet(oids), not stars, so don't produce their own light. 3. They are probably very cold and don't emit much in the IR spectrum. 4. They may have low albedo, coupled with their distance from the sun, means they reflect very little visible light. 5. Space is huge. Trying to spot a tiny, dar…
Like the parent, this seems odd that just now in 2016 we find there might be another planet in our own solar system when planets are being discovered in other solar systems and galaxies all the time. There's this from the article: "For the first time in over 150 years, there is solid evidence that the solar system's planetary census is incomplete." It's our _own_ solar system and we just now found this massive thing?
Well, we've not yet found it. There is just a very good case for it's existence.
Also, it's arguably easier to find planets in other solar systems because from our vantage point we can observe the stars and measures the dips in light as the planet transits the star (from our perspective). We can't do that without our own solar system given we too are orbiting the same star as the planet we would want to detect.
Also, remember this planet has an orbital period of about 10,000 - 20,000 years, according to the article. It would have just barely completed one orbit since humans started farming.
Re: Caltech Researchers Find Evidence of a Planet Beyond Pluto
#120Earlier quoted context omitted.
Just to offer some context in layman's terms: 1. These objects are very, very far from the sun (and Earth). 2. These objects are planet(oids), not stars, so don't produce their own light. 3. They are probably very cold and don't emit much in the IR spectrum. 4. They may have low albedo, coupled with their distance from the sun, means they reflect very little visible light. 5. Space is huge. Trying to spot a tiny, dar…
Like the parent, this seems odd that just now in 2016 we find there might be another planet in our own solar system when planets are being discovered in other solar systems and galaxies all the time. There's this from the article: "For the first time in over 150 years, there is solid evidence that the solar system's planetary census is incomplete." It's our _own_ solar system and we just now found this massive thing?
One of the main methods we use for finding planets in other systems is watching for them to cross our view of the star -- basically, looking for a star to slightly dim in a periodic fashion, something akin to an eclipse.
With objects in our own system that don't emit light of their own and are much farther away from the sun than we are, they'll never block the light from the sun. If by sheer luck they happen to pass in front of another star and temporarily block it, it's still difficult to figure out what the object was, how fast it was moving, and so on and therefore difficult to correlate with "something in our own system".
Keep in mind, the solar system is REALLY big. "Planet Nine" is proposed to be some 55+ billion miles away, or about six hundred times as far away from the Sun as Earth is.