Actually, no, there’s another time that matters: how long will it take to invent a better probe? There’s not much point in building a probe that takes 1000 years to get somewhere if 50 years from now we can build one that’ll get there in 100. In other words, we shouldn’t bother to build probes that will simply get passed by more advanced ones built later.
I couldn’t begin to demonstrate the math, other than that it involves an inverse square relationship. So if you are standing on a bigger planet, the gravitational pull generated by the larger mass overall is significantly counteracted by the longer distance between you and the planet’s center. Jupiter has nearly 318 times Earth’s mass, but its radius is about 11 times greater, so the Gs at its visible surface, if you could stand on it, would only be about 3. I attempted to work out the math like this, where Earth’s values are 1.
317.8 Earth masses / 121 = 2.62g – fairly close, but I suspect there’s some other factor, presumably a constant, that I’m missing. When working out the Earth versus the Moon, I came up with only 5 lunar gravities for Earth, which again is close but not quite right.
Are there any real astronomers here who can clean up my spotty math?
As for what life would be like, I imagine it would be helpful to be in water, either swimming or spending most of your life semi-submerged, as some of the largest dinosaurs are assumed to have done. I wouldn’t expect much in the way of land evolution.
The constant doesn’t matter, since you’re looking at ratios, so it’ll cancel out. As for getting a factor of 5 difference between the Moon and the Earth, that’s probably just accumulated roundoff error.
I guess fans of the Drake equation are busy revising their guess at n[sub]e[/sub] (n[sub]e[/sub]: the average number of planets that can potentially support life per star that has planets). As the Bad Astronomy article says, this discovery suggests that planets potentially supporting Life As We Know It are quite common.
Oh, and I appreciate Wendell Wagner actually showing the working behind that 1.7g number, rather than just baldly stating it.
I don’t know about that. We could easily end up waiting for some super-fast probe for longer than it would take a probe we could build with current (or not that far-off) technology to get to the planet and send data back.
Columbus didn’t wait around for the advent of supersonic aircraft to get to the New World.
[quote=“Mr.Excellent, post:30, topic:555593”]
The question is whether after 200-400 years we will either have advanced far enough so that our fastest ship would pass the probe along the way, or have wiped ourselves out to the point that the return signals fall on deaf ears.
Cathedrals and other monumental buildings are constructed by wealthy oligarchies in a display of manifest divinity. They’re basically built at the behest of and by the force of will of a single individual or small group, at the expense of a large amount of forced labor. No one has built a grand cathedral comparable to Notre Dame de Paris in several hundred years. With a few exceptions (mostly monuments to hubris like the Libyan Great Manmade River Project) virtually all major civil engineering efforts have been toward a structure that benefits a large number of people, like the James Bay Project, the Indus River Irrigation Program, and the Tennessee Valley Authority. We can’t even Congress to sign up to an annual budget on schedule. What makes you think that we can pull together enough support to maintain consistent funding for 10-20 years for the most ambitious, risky, and most expensive project ever attempted by humankind?
And the problem still remains of how to make such a vehicle sufficiently robust to continue operating for several centuries without any kind of external maintenance, which is vastly beyond any existing reliability engineering experience for complex electronic and mechanical systems. Cathedrals and civil structures are largely a challenge of logistics and labor; building an interstellar space probe is (in addition to that) a massive technical challenge for which the solutions do not yet exist. It’s not impossible, but it is beyond the current state-of-the-art. Heck, just delivering and assembling such a large, complex vehicle in orbit would be a huge technical and logistical challenge. The lower end of an Orion-type vehicle is around 1000 tons, or roughly ten times the maximum payload of the Saturn V rocket to LEO, or forty times the STS/Shuttle capacity to the same orbit. That represents nine continuous years of peak historical STS launch activity (1986 through 1994). Basically, you’d need to develop reliable, robust, and reasonable cost Earth-to-orbit super heavy lift capability just to support taking components to orbit.
Stranger
Near as I can tell things like warp drive are not even theoretically possible.
So, there is no likely chemical rocket that will be invented between now and whenever that will produce a far superior rocket. They know that stuff pretty darn well now.
Other methods such as laser or ion propulsion are also well understood and new tech will not improve their limitations.
In short I am not seeing some super tech for propulsion that we don’t already understand coming along that would change how fast we can get to another star. It really would take the invention of some sci-fi propulsion (finding a way to mas produce antimatter would help a lot but if you think nukes are bad fear the day someone can mass produce that stuff).
So, may as well get on with it now. If something better comes along then great! I’d love to see it. As far as we know though (and not because someone hasn’t thought of it yet but because of the very limits of physics itself) that stuff will remain sci-fi.
Seen a lot of news blurbs on this today. It’s being called the Goldilocks planet. Its variously, proof of life on other planets, a likely place to find extraterrestrial life, just like Earth, a planet in our solar system, and/or proof of extraterrestrial intelligence. If it’s just like earth, their journalists are idiots too.
I find this somewhat interesting. But I’m surprised by the hoopla. I doubt we know much about this planet at all. I don’t think it even indicates a greater chance of extraterrestrial life at all. There is no serious doubt that other planets exist. And this one is not even that much like Earth. If it’s not rotating, half the planet will be very hot, and the other half very cold. The speculated moderate zone in between probably doesn’t exist unless there is water (or other liquid) or an atmosphere on the planet, and we don’t know that there is.
An awful lot of planets like this might be detected before, or if, we find life somewhere else.
What are the odds of imaging this planet, in say the next 50 years? Is there any possibility of technology that could provide even a blurry look?
If you were pulling straws out of the middle of a haystack and before long pulled out a red straw, would you think “hmm, I guess I found the one red straw”, or would you think “there are a large number of red straws in this haystack”?
(assuming you have no prior knowledge of haystack composition, and there isn’t some farmer standing there winking at you.)
I would think I should kill myself if I have nothing better to do than pulling straws out of a haystack.
Does this relate to my post in some way?
Beyond spectral imaging of the atmosphere (which may actually allow us to make some very useful inferences, particularly if is a strongly oxidizing atmosphere like Earth’s) direct imaging will never show more than a tiny dot at interstellar distances, and then only from a large worlds; most planetary bodies are and will continue to be discovered by planar transit, Doppler spectroscopy, or gravitational lensing. The problem with direct imaging is two-fold: one problem is that the intensity of incident light is very low in comparison to the parent star, and the other is that when the planet is near its maximum aspect to be observed (i.e. its “phase” is nearly full) it is either nearly in line with its star, or we’re observing the system well out of plane, which means our observed aspect of the starlit side is small regardless of its position in orbit. I doubt it will ever be possible to detect an Earth-sized world by direct imaging at more than a few parsecs, as the actual incidence in any locus will be so small that the blur it would make as it moves in orbit will be indistinguishable from background noise.
Stranger
Well, you point out various ways in which this planet is thought to be unlike Earth. But the point is, it is still a bit like Earth, and it’s one of the few planets outside our solar system that we’ve looked at. If we can find such a match, albeit not a very good match, by only looking 20 light years away, then it *suggests *that, among the vastly greater number of planets in our galaxy (100,000 light years across) and the unimaginably greater number elsewhere, there may be many Earth-like planets out there.
That’s what I thought before this planet was noticed. But so far, nothing about this one makes it anymore likely to have signs of life, or be a good vacation destination, than the less similar ones. We may find many planets like this one, or even more similar to Earth that don’t meet that criteria. I did say it was somewhat interesting though. IMHO just not worthy of the hype, unless we get more information.
Going back to the original (and erroneous) query of the OP, Human being pass out at five Gs. So, a five G planet would NOT be conducive to human habitation.
No one is saying that this planet is likely to support life. The point is that it is thought to be slightly less unlikely to harbour life than other planets that we have discovered so far. Maybe one probability is 0.000001 and the other is 0.00000000001. You may think “So what? They’re both insignificantly small probabilities”, but multiply them by the colossal number of planets in the universe and the difference becomes important.
Although in what is defined as a habitable zone, it is not very Earth-like in many of its salient properties, and one sample does not a statistical distribution make. However, we have no reason to believe that the Solar system is in any way particularly special. The Sun is a very average sized main sequence G-type yellow dwarf (luminosity class V). F, G, and K stars in luminosity class IV and V (subgiants and dwarfs) comprise around 20% of all stars in the observable neighborhood and have reasonably broad habitable bands in which it is reasonable to assume that rocky worlds may orbit with parameters that are suitable to support liquid water and therefore life as we may imagine it.
It would, in fact, be surprising to discover that the Solar system is an outlier in its distribution and composition of planets, although the actual conditions under which life may come to form, and especially multicellular life (much less cognition and intelligence) are poorly understood and may or may not be vanishing rare.
Stranger
Well, what Stranger said.
And yesterday I was sure planets like this one existed. Today’s news hasn’t changed that.
Quoth Iggins:
If you just want to see the planet distinct from its parent star, there are NASA missions for which the technology is pretty much already there and they’re just awaiting funding which could do the trick. For being able to make even a map of the surface, though, it’d probably be easier (though slower) to send a probe there than to build a telescope here that could do the trick.
Quoth Stranger on a Train:
Actually, we do have some reason to believe that our Solar System is special: Current computer models of solar-system formation tend to predict mostly systems which look very much unlike ours (though I suspect that such models are unduly influenced by current exoplanet observations, which have strong selection effects in them). And the general principle that we should not assume that our place in the Universe is special is here negated by the weak anthropic principle: Even if solar systems with a planet in the habitable zone were rare, we would still find ourselves on one.
That said, though, I don’t think anyone is really surprised at the existence of planets in the habitable zones of other stars. The only reason we hadn’t discovered any prior to this is that our primary methods of planet-detection are biased towards planets that are very close in (and also very massive). But really, the habitable zones of most stars are broad enough that it’d probably be more surprising to not find planets there: It’s not like picking out a red piece of hay; it’s more like picking out a grayish-yellow piece of hay.