NASA’s Kepler Mission Discovers Bigger, Older Cousin to Earth • Hacker News Board

Re: NASA’s Kepler Mission Discovers Bigger, Older Cousin to Earth

#301

Post by darkmighty » Sat, Jul 25, 2015, 7:01 AM UTC

greeneggs wrote: post #276

Pharaoh2 wrote: post #241

Earlier quoted context omitted.

Are you sure it will be probably less than 1 order of magnitude? Unless there is some restriction that limit the plane of the orbit around a star with relation to the galaxy, which is unlikely... Assume the plane needs to be within 1 degree from the line joining the star and kepler. I would guess it probably less. It would be a function of size of the planet, size of the star, radius of the orbit and distance of star…

> Assume the plane needs to be within 1 degree from the line joining the star and kepler... That would give about 179 planes that we cannot see... Assuming you mean 1 degree in either direction, or 2/360 = 1/180, this is off by about a factor of pi/2 ~= 1.57. The correct answer is sin(pi/360) ~= pi/360 ~= 1/115. Still two orders of magnitude, but slightly better. The reason is that the degrees are not equally likely…

Ah that's some good analysis. I would love seeing this calculation done precisely, for that 30 light year figure (and other distances). There's other factors to put in too whose significance idk like the size of the sun -- if it's much larger this increases significantly the range of angles in which occlusion occurs.

Re: NASA’s Kepler Mission Discovers Bigger, Older Cousin to Earth

#302

Post by [deleted] » Sat, Jul 25, 2015, 10:23 AM UTC

darkmighty wrote: post #301

greeneggs wrote: post #276

Earlier quoted context omitted.

> Assume the plane needs to be within 1 degree from the line joining the star and kepler... That would give about 179 planes that we cannot see... Assuming you mean 1 degree in either direction, or 2/360 = 1/180, this is off by about a factor of pi/2 ~= 1.57. The correct answer is sin(pi/360) ~= pi/360 ~= 1/115. Still two orders of magnitude, but slightly better. The reason is that the degrees are not equally likely…

Ah that's some good analysis. I would love seeing this calculation done precisely, for that 30 light year figure (and other distances). There's other factors to put in too whose significance idk like the size of the sun -- if it's much larger this increases significantly the range of angles in which occlusion occurs.

[deleted]

Re: NASA’s Kepler Mission Discovers Bigger, Older Cousin to Earth

#303

Post by darkmighty » Sat, Jul 25, 2015, 10:24 AM UTC

greeneggs wrote: post #276

Pharaoh2 wrote: post #241

Earlier quoted context omitted.

Are you sure it will be probably less than 1 order of magnitude? Unless there is some restriction that limit the plane of the orbit around a star with relation to the galaxy, which is unlikely... Assume the plane needs to be within 1 degree from the line joining the star and kepler. I would guess it probably less. It would be a function of size of the planet, size of the star, radius of the orbit and distance of star…

> Assume the plane needs to be within 1 degree from the line joining the star and kepler... That would give about 179 planes that we cannot see... Assuming you mean 1 degree in either direction, or 2/360 = 1/180, this is off by about a factor of pi/2 ~= 1.57. The correct answer is sin(pi/360) ~= pi/360 ~= 1/115. Still two orders of magnitude, but slightly better. The reason is that the degrees are not equally likely…

Indeed taking into account that the sun is much larger than earth I got the value of P=0.00465 by taking P=sin(arctg(solar radius/1 au)). So the planet size actually shouldn't matter significantly on this particular probability, since the planetary radius is like 1% of the solar radius.

Re: NASA’s Kepler Mission Discovers Bigger, Older Cousin to Earth

#304

Post by macspoofing » Sat, Jul 25, 2015, 2:03 PM UTC

Cyph0n wrote: post #193

omonra wrote: post #179

Earlier quoted context omitted.

Was anybody but Arabs involved in the conquest of the early 7th century? Ie I'm sure other people took on Islam afterwards but he was talking about a specific point in history. We don't call the Spanish conquest of the Americas a Christian one even though they were Christians who ultimately converted everybody to Christianity.

Quite a few of the Prophet's companions were not Arabs, but yes the majority were. Nonetheless, it is more correct to identify as a Muslim before an Arab. What irritates me greatly is when historians refer to the Muslim scientists of the Islamic Golden Age as "Arabs", when most of them were not Arabs at all. It's such a simpleminded and sweeping generalisation that clearly shows the thoroughness of the so-called orie…

>What irritates me greatly is when historians refer to the Muslim scientists of the Islamic Golden Age as "Arabs"

To me it's strange to ascribe such areas of study to the religion. What does Islam really have to do with optics besides Ibn Al-Haytham being a Muslim? No one ever ascribes enlightenment science as 'Christian science'.

Re: NASA’s Kepler Mission Discovers Bigger, Older Cousin to Earth

#305

Post by MertsA » Sat, Jul 25, 2015, 9:33 PM UTC

guimarin wrote: post #180

johnchristopher wrote: post #113

Earlier quoted context omitted.

There was an kind of on-topic post on imgur about that today: [The Fermi paradox: We're pretty much screwed...]( http://imgur.com/gallery/Wtog9 )

I find myself thinking that the existance of Dark Energy/Dark Matter is the solution to the fermi paradox. there is some kind of energy creating system which creates dark matter. This matter is no good for normal matter so it is transported far away from stars/galaxies and dumped. This would probably be true if we could create a physics model that can explain like 1% of Dark Matter occurring naturaly. Then we just as…

Or maybe there is no Dark Matter and we can't see a huge portion of stars because all of the light is being captured like a Dyson sphere. Unfortunately both of those hypotheses are rather improbable, we can observe very very distant galaxies and they all seem consistent with respect to Dark Matter AFAIK.

Re: NASA’s Kepler Mission Discovers Bigger, Older Cousin to Earth

#306

Post by Gravityloss » Mon, Jul 27, 2015, 10:55 AM UTC

flashman wrote: post #229

Gravityloss wrote: post #111

The significance is this: it's very likely that there are a lot more such planets a lot nearer to us. This is because Kepler can only detect planets which lie in the same plane as earth and the star so the planet occults the star. Assuming random distribution, there's probably thousand fold amount of off plane planets. There are 259 stars within about 30 light years. Communication could be conceivable with such dista…

> Assuming random distribution, there's probably thousand fold amount of off plane planets. For a star like ours with a single Earth-size planet at 1AU, the odds of observing a transit are 0.47%. There is a page devoted to this question which gives some idea of the variables involved: http://certificate.ulo.ucl.ac.uk/modules/year_one/NASA_Keple...

Thanks, that's an excellent response!

Assuming a constant density of earth like stars, a density of 200 earth likes in a 1500 light year sphere would mean one earth like in 250 light year sphere.

Assuming a disk instead, it would be about 100 light years.

Don't know how it relates to the local star neighbourhood... https://en.wikipedia.org/wiki/Orion_Arm

Of course, sampling from this small amount of data is pretty prone to problems...

Re: NASA’s Kepler Mission Discovers Bigger, Older Cousin to Earth

#307

Post by Bill2156 » Wed, Jul 29, 2015, 1:06 AM UTC

tempestn wrote: post #245

oberstein wrote: post #178

Earlier quoted context omitted.

Donate to the relevant parties. Unless you're already very old or very sick, it's hard to say you're condemned. A lot can happen in the next 40 years.

Indeed. FTL travel not so much, but working cryonics (with revival) isn't _that_ far-fetched in a reasonable timeframe.

Cryonics with revival is far, far closer in technological achievement (and actually has working science associated with it) than is any realistic FTL travel. Worm holes, Einstein...and those who have further derived his special and general theories of relativity, namely Alcubierre, Natario and White, all towards a "warp" type drive, are at best "speculative". One step above educated fantasy at this point. No working science. Just incomplete math and ideas. FTL.. warp and worm holes are thousands, if not tens of thousands of years beyond us. A suspended animation scenario... about 100 to 150 years....if that far.