Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Caltech Researchers Find Evidence of a Planet Beyond Pluto

caltech.edu

Post reply on HN
Print view View original

101–110 of 159 posts

Re: Caltech Researchers Find Evidence of a Planet Beyond Pluto

#101

Post by abecedarius »

hmahncke wrote: post #11
antognini wrote: post #9

Earlier quoted context omitted.

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…

Also, we don't know where in its orbit the planet happens to be right now. If we're lucky, it's relatively close to the sun, and it will be detectable. If we're unlucky, it's relatively far away from the sun, and it could easily be undetectable by current observatories because the orbit is so eccentric. [Source: I saw Mike Brown give a talk on this topic at the Cal Academy of Sciences, where he hoped he was lucky...]

Note that an eccentric orbit spends most of its time out in the far reaches, since it moves much slower out there. The odds are against the happy case.

Re: Caltech Researchers Find Evidence of a Planet Beyond Pluto

#104

Post by elbigbad »

SadismoNoise wrote: post #93
hackuser wrote: post #48

The NY Times covers the story well: http://www.nytimes.com/2016/01/21/science/space/ninth-planet... EDIT: After reading the comments in this discussion, many of which are addressed in the NYT article, I'd say the NYT article is almost certainly worth reading.

https://www.youtube.com/watch?v=TkBMAHUkibY

I really like the people and format of HN. Unfortunately these kinds of posts (random gifs, memes, video links) really detract from it. Luckily they only come up sporadically and when they do they're quickly gone.

Re: Caltech Researchers Find Evidence of a Planet Beyond Pluto

#105

Post by xenophonf »

No 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 it should be possible to find the object proposed by the Caltech astronomers here (10x the mass of Earth at around 600 AU). I don't know if WISE's current condition would allow it to perform such a search, as it's completely out of coolant.

Re: Caltech Researchers Find Evidence of a Planet Beyond Pluto

#106

Post by davesque »

SadismoNoise wrote: post #93
hackuser wrote: post #48

The NY Times covers the story well: http://www.nytimes.com/2016/01/21/science/space/ninth-planet... EDIT: After reading the comments in this discussion, many of which are addressed in the NYT article, I'd say the NYT article is almost certainly worth reading.

https://www.youtube.com/watch?v=TkBMAHUkibY

It was just a joke, people. Lighten up.

Re: Caltech Researchers Find Evidence of a Planet Beyond Pluto

#107

Post by Balgair »

tdaltonc wrote: post #25

> 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…

I knew Chaz personally in undergrad and a bit since then. Though I have not read the article yet (I'm in a state of shock really) I can attest to the man. He is so kind, funny, personable, and one a heck of a guitar player. Based on his stellar work in undergrad in modeling the orbital path futures of our solar system on the Gyr timescale, I am sure he is sure of the work. (Only non humanities major to ever win the Dean's Award at UCSC, it was great work)

The man would not ever publish this unless he was sure of it. Science and time may tell him wrong, but I'm one to believe him as a friend. Both he and Olga must be on cloud nine right now! (oh wow, nine, wow!)

I mean WOW! Like, a PLANET! A frickin PLANET! None of this dwarf stuff, a full PLANET! (Not to malign all those folk's hard work in finding the dwarves either).

Jesus tapdancing christ gravy! What a day!

EDIT: Upon further reading, it may still be a dwarf planet as it has not 'cleared' it's orbit. Still, my lord, so happy for them both right now!

Re: Caltech Researchers Find Evidence of a Planet Beyond Pluto

#108

Post by XorNot »

jerf wrote: post #83
jessriedel wrote: post #36

Earlier quoted context omitted.

I think you're right that that's one of the chief concerns, but I think you paint it incorrectly as a technical problem. ("Multiple comparisons" as you call it. Particle physicists call it the "look-elsewhere effect": https://en.wikipedia.org/wiki/Look-elsewhere_effect ) The easy, though tedious, part of the look-elsewhere effect is to calculate a probabilisitic correction for all the various combinatorics of X objec…

I'd also observe that in terms of prior probability, "There is a ninth planet in the solar system that we have not yet detected" is probably hovering at least in the low-integer percentages, and I imagine some scientists would place it higher than that. The general idea is not a wild, far-out one by any stretch of the imagination.

That isn't how probability works though. You have a Bayesian priors problem - you can't establish what the initial probabilities are.

Re: Caltech Researchers Find Evidence of a Planet Beyond Pluto

#109

Post by InclinedPlane »

logingone wrote: post #15

I 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?

Planets are small. A planet 4x the diameter of Earth but 300+ AU away is a factor of about 1 to 1 million. That's equivalent to a single grain of sand nearly a kilometer away.

Re: Caltech Researchers Find Evidence of a Planet Beyond Pluto

#110

Post by noselasd »

SolarNet wrote: post #35
theptip wrote: post #29

Did 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 always reconed Kerbal was inspired by http://www.agi.com/products/stk/ , heavily used in the space industry
Post reply on HN