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Three Neptune-sized Planets Found Nearby
WillAffleckUW writes "CNN reports the discovery of three Neptune-sized planets found in orbit around a sun 41 light years away. The star they orbit is similar to our Sun, and the planetary distribution is probably similar to our Solar System. Recent observations by NASA's Spitzer Space Telescope last year revealed that HD 69830 also hosts an asteroid belt, making it the only other sun-like star known to have one. No word on if they have habitable moons, or monoliths yet."
For those of you not immediately familiar with exactly what a Neptune-sized object is, it is about 12.645679 sextillion Volkswagens (go ahead, look it up. I have time). Now, as to why they would categorize an object that is 41 light-years away as 'nearby' is another question.
(Go ahead, tell me the tale of how immensely huge the universe is and how 41 light-years away can only be described as nearby. Then tell me you won't mind helping me move if it's 'nearby')
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As opposed to something that is over 7,000 - 10,000 light years away, 41 isn't very far. I mean it's no Alpha Centauri, but it's close in astronomical terms.
...and that's the way the cookie crumbles.
ba-dum-cha. Thank you, thank you, I'll be here all week.
There could be sentient being living there. Odds are 50/50 they have more advanced technology than we do. If they can travel at near light speed, they could arrive here 82+ years after we started beaming massive amounts of radio and tv into space, which would be soon. Maybe we should prepare a "reception" for them or something.
It's only a matter of time until somebody picks up our signals and comes to crash the party.
Nearby, like many words, is not an absolute term. It is relative to the scale of the things involved. No, 41 lightyears is not nearby if you're talking about the distance from your house to the nearest gas station, but when you are talking about interstellar distances, 41 lightyears is much more near our sun (i.e., nearby) than say a star on the opposite side of the Milky Way.
Think of it like this. We'll use another word whose meaning is varaible in a similar way: close. A scafolding platform collapses and a pile of bricks comes within one foot of crashing down on you. You might say, "Wow! that was close." You throw a pitch in a ball game and you throw wide one foot left of the strike zone. No one would call that close. You'd need to be in a range of, say, a centimeter from the plate for a pitch to be called close.
my pet machine
We might not have the technology to travel there physically in my lifetime (or lifespan, whatever) but that should be close enough to warrant some refocusing of more than a few SETI dishes. And for the longer term maybe a satelite designed to last 500 years to send there. This might be a project worth investing in even though we will be long gone before it would achieve fruition.
We are all just people.
Yeah, some might consider this a possible life site. But how can we know the planets are indeed distributed as they are in our Solar System, with a rocky planet with the right elements located in zone around the star that can support liquid water for billions of years?
Also, three Neptune sized planets probably would not protect such a terrestrial world against frequent life-exterminating collisions as our Jupiter and Saturn (and to a lesser extent Uranus and Neptune) have done. Neptune is no where near Jupiter's size, and Jupiter has almost certainly saved us from death.
I'm really impressed by the speed of progress here. I'm hoping that in ~30 years, we'll actually be able to SEE these planets. That's really exciting!
I'll form my OWN solar system! With blackjack! And hookers!
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Yeah? And I'd like to know why this country spends HUNDREDS of billions of dollars on unnecessary wars. One gains knowledge for all mankind, the other pisses off the rest of the world and generates more enemies for us to have to fight down the road. I'd say the billions for space study is much more worthwile than many of the other things we do.
Assuming we can spot Neptune sized planets, if we were looking at our Solar System, we would see four planets well outside the "habitable" zone. Here we see three big rocky planets where only one is "just inside" the habitable zone--and I rashly assume it's just within the too-hot side (the outermost planet has a year of 197 days, compared to Venus's 224).
How is this "similar"? Seems pretty different to me...
It wasn't that long ago (err, wow, 10 years, maybe that's long) that the first extrasolar planet was discovered. I still remember that news announcement I watched on TV...
Anyway, since the discovery of those 3 planets, another planet has been found. Check out the exoplanet encyclopedia (my favourite exoplanets site). It has a catalog with all the data of those planets, some with uncertainty factors. Discovery method, size, catalogue number, the whole lot. Try chucking all that into a spread-sheet, and plot some scatter graphs. Should be a lotta fun. The last time I tried this, it was a bit problematic because the masses are not really known (for planets discovered using spectral shifts), but are merely minimum (maximum?) limits only. But still, an order of magnitude plot could be fun.
Anyway, the 3 planets are already in the catalogue under HD 69830. Don't forget to check out this one as well. Exciting times. I look forward to 200 planets!
Assuming that Bode's Law applies there, it's a reasonable assumption that a planet resides within the habitable zone around that star.
However, unless it has through some miracle of coincidence a large moon to provide the environment of constant change via tides and crustal flexing, I doubt that Darwinian processes would have had the time to produce an ecosphere like ours. Maybe something along the lines of the Paleozoic era might be possible.
But then, with an asteroid belt comes catastrophic encounters, and maybe that would be the larger driving influence for Darwinian change.
But in any case, I doubt that the coincidence would be strong enough to extend to a similarity of geography that would support an ecological mechanism similar to ours, that regulates climate change between two quasi-stable regimes.
Quite possibly, once life developed on such a world it might quickly drive it into a greenhouse state like Venus, without the mechanisms that switch us between greenhouse and icehouse that we have.
We spend more on foreign aid in the US than we do on NASA. And I'm not counting any of the goings on in Iraq or wars as foreign aid, either.
Space travel is a fraction of the budget. The RIAA makes more money every year than the NASA budget for any given year. And they've contributed nothing to man kind like NASA research has. Just, you know, for some perspective: We waste more money on shitty music than the government spends on NASA and research.
Yes, there is a limit.
That limit is 6 solar masses. Think about it: 6 times the mass of our sun. Made of rocks.
Why the limit? Because that is the mass of an object, after which it will collapse in on itself to form a black hole. I don't know enough of the science to be able to state at what point the center of the planet begins to form neutronium, but the surface at least, will remain rocky, until the object does completely collapse.
Rocky is just "rocks" and rocks are happy to sit in a very high level of gravity. Your 5 solar mass rocky world might have mountains that reach as high as 3 or even 4 millimetres, and fantastically deep trenches up to 2 mm deep might form during "earthquakes".
The only questions in my mind are:
1) How long after the thing stops accreting material does it take to form a rocky surface?
2) What is the surface gravity of a 5 solar mass rocky world?
3) At what point does the interior begin to form Neutronium.
How many escape pods are there? "NONE,SIR!" You counted them? "TWICE, SIR!"
Suppose one light year is 1 km. Then the tinyest speck of dust on the monitor is about 5 times bigger than Earth (1 micron), Sun is about half the size of the dot above i (0.1mm), distance from Earth to Sun is the length of the word "length" (1.5cm). The size of the Solar system (Pluto orbit) is about the size of your computer - 0.7 meter. The most distant objects in Oort cloud are probably within your room (a few meters). The nearest star - 4km away, like a gas station. The new planets are 41km away - the state border :-). Our Miky Way galaxy is a few times larger than Earth, maybe half way to the Moon. The nearest spiral galaxy is not too far - just 8 times more distant than Moon. The edge of the Universe (12 bln l.y.) is about the size of Sedna orbit.
So, 41 light years is relatively near :-).
Dude, you could at least give some attribution to http://starchild.gsfc.nasa.gov/docs/StarChild/ques tions/question19.html
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IANAP (I Am Not A Physicist), but my bet would have been on the Chandrasekhar limit there, which puts the limit at a little under 1.5 solar masses. (Admittedly, that does change with the chemical composition, so no idea how that works for heavy enough elements associated with "rocks".) Since we're talking a planet, not a star, I'll assume there was never nuclear fusion in the centre to generate extra pressure, so the limit would be purely and only the limit at which degenerate electron pressure is no longer enough.
Also, rocks (solids, metals, whatever) may be happy to sit in high gravity, but not _that_ high, or not without remaining the same kind of thing one calls a "rock" in casual conversations. A mass supported by electron degeneracy pressure isn't quite the same as the mostly crystalline structure you'd have in mind for a "normal" rocky planet.
I'm also not sure if it would form mountains or trenches (even 3 to 4 mm high) at that point, since the whole thing is held together by the quantum pressure of a "gas" made of electrons. It's, so to speak, some atoms "floating" in that electron gas. What keeps it from collapsing at that point isn't a crystalline structure that can be re-shaped to form a mountain or a trench, but just the fact that getting any denser would force the electrons to occupy even higher energy states, thus increasing the pressure, thus pushing it back into shape. So at a wild guess, that thing couldn't form any long lived mountains any more than you can get mountains on Jupiter.
I'm also not sure if you can get just a little neutronium in the centre, while leaving the surface intact. The way I understood it (but again, IANAP) once it does start to collapse into neutronium, then it goes all the way. (Maybe also blowing a part of itself into space, supernova style. The fast collapse will produce enough energy for that.) If the pressure is enough for the centre to collapse, this will just produce an avalanche reaction where the collapse both increases the gravity (less R --> more g) _and_ takes out some of the electron gas that supported the star to start with. So basically it's like puncturing an inflated balloon: it won't stop at losing just a little gas.
That's why we talk about the Chandrasekhar limit as a hard limit. In fact, hard enough to use Type Ia supernovae as a standard candle for really long range astronomy. You can know pretty exactly at what mass the star went *BOOM* and exactly how bright that explosion was. Because it happened as soon as the star went even a just a tiny little bit above that limit. When that happened, it didn't just get a little neutronium in the core, but started the final countdown.
But again, IANAP, so I'd be curious to hear about it from a real physicist.
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