51–60 of 159 posts
Did anyone else notice that the rendering of the orbits in the article looks strikingly similar to Kerbal Space Program's orbit UI?
I did :-) Maybe they use Kerbal to render the results of "real" simulation software?
If it holds up, this is fantastic. Given how interesting the Pluto system has turned out to be, I can only fantasise about a potential super-earth system relatively nearby. However, to be completely pedantic: would this actually be a planet ? Or still a dwarf planet , despite its massive size? Keep in mind that the definition of planethood is not only that it's large enough to be rounded by its own gravity, but that…
From what I understand, it has cleared the space but there are still harmonic crossings that can't be cleared. Interesting challenge to the new definition - must the orbit be clear, or only clear sailing through the orbit.
> 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…
http://www.dummies.com/how-to/content/how-to-calculate-six-s...
What I mean is that in human terms, Google says the average man is 5'9" with standard deviation 2.9 inches, then 3.8 sigma (the chances of this happening by chance) are the same as the chances of finding someone 6'8". It doesn't seem unbelievable - https://answers.yahoo.com/question/index?qid=20101208183308A...
If a woman is set up on a blind date and told the guy is 6'8" would she find it like not credible?
My understnading of statistics then is that the idea that there just so happens to be a planet ten times the size of Earth in our solar system is pretty unbelievable. So I'd want the chances of it being an experimental fluke to be lower than seeing a 6'8" guy, anywhere, at any time, in any context. Because I would think that's what happens when you look at enough data.
- Aren't the chances of this being completely spurious literally exactly the same as a researcher saying "I saw a 6'8" guy somewhere", meaning anywhere, in any context?
Wouldn't you want higher evidence before stating "evidence found for ninth planet in our solar system, ten times the mass of Earth"?
> 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…
More specifically, quoting from that page, "all Kuiper belt objects with orbits that do not veer into inter-planetary space and spend longer than approximately 2000 years to complete a single revolution around the Sun... trace out elliptical paths that point into approximately the same direction in physical space, and lie in approximately the same plane."
That could be just an observational coincidence, and that's where they claim the statistical figure that you've cited. I have no idea to what extent those figures account for the multiple comparisons issue, but the range of orbital parameters that I've quoted here doesn't look very fine-tuned to me. (The upper bound certainly isn't, anyway!) So it's just a question of how the lower bound was chosen. And on some level, I'm not even sure that that's an issue: an observation that's based on "the longest N bound orbits all show this pattern" feels meaningful to me even if I'm not sure in advance how big N is going to be.
Why 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…
[0]https://en.wikipedia.org/wiki/2012_National_Reconnaissance_O...
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?
Provocative title for this Caltech press release. Mike Brown, the co-author of the paper reported here, discovered Eris, a KBO like Pluto, in 2005. This discovery prompted the IAU in 2006 to demote Pluto out of the realm of "planet" into a "dwarf planet". At the time, Alan Stern's New Horizons mission to Pluto had just been launched, it finally arrived last year. Stern was incensed that NH started out as a visitor to…
Giant, weird orbit, debate ... there can be only one name. This is Planet X. Also because X would be 10th discovered planet, a reference that pluto, while not a planet today, was indeed the ninth _discovered_ planet.
> Ceres was the first asteroid discovered, by Giuseppe Piazzi at Palermo on 1 January 1801. It was originally considered a planet, but was reclassified as an asteroid in the 1850s when many other objects in similar orbits were discovered.
> [...]
> Ceres was assigned a planetary symbol, and remained listed as a planet in astronomy books and tables (along with 2 Pallas, 3 Juno, and 4 Vesta) for half a century.