'Hundreds of Worlds' in Milky Way

Raphael Emportu writes "BBC news is reporting that rocky planets, possibly with conditions suitable for life, may be more common than previously thought in our galaxy, a study has found. New evidence suggests more than half the Sun-like stars in the Milky Way could have similar planetary systems. There may also be hundreds of undiscovered worlds in outer parts of our Solar System, astronomers believe. Future studies of such worlds will radically alter our understanding of how planets are formed, they say."

Comments

No shit.

[Anonymous Coward]

No shit that there are other planets like ours out there. The incomprehensibly massive scale of the universe dictates it to be true, statistically-speaking.

Today, children receive next to no education in the field of astronomy. Were they to have a proper understanding of what lies beyond Pluto, they'd probably grow up to realize how silly it is to believe that there is only one planet like Earth.

Re:No shit.

[meringuoid]

Imagine we discover: That the chance of a star to have planets is one in a million. Doesn't seem impossible, does it? The chance of a star with planets to have one at the correct distance (taking star heat in consideration) to be between 0 and 100 C, one in a billion. The chance of a planet in the correct position to have water. One in a million.

Point 1: very long odds, given the number of extrasolar planets we've already discovered.
Point 2: extremely long odds. It's a reasonably wide zone for the Sun, from about halfway between Earth and Venus out to Mars - which would probably be inhabitable if it were larger and could hold a thick atmosphere. Moreover the zone will shift as the star evolves and brightens, so a planet that starts out frozen may spring to life in later years. Come the red giant phase even Titan might bear life.
Point 3: totally redundant. It just repeats point 2, but for some reason does so with a probability greater by a factor of one thousand. Counting the same criterion twice just to get the numbers down by a factor of a million is cheating.

So, we still have nine planets. Now, cross your fingers that one of those is not radioactive, doesn't show the same side to the star (that happens quite often), is big enough to have enough gravity to hold an atmosphere, etc.

How do you know that tidally locked planets are commonplace? There are none in our system.

Well, it's nice to have a destination...

[Thanshin]

Now, if we only had some means of reaching it...

The speed of light is a barrier like few the humanity has ever found.

Re:Well, it's nice to have a destination...

[IndustrialComplex]

I don't know if I agree with that assessment. It seems to me as if H. Ergaster simply progressed as far as his brain would allow, and no farther. A simple hand axe was just the apex of his ability. Looking at H. Ergaster makes me rather worried about the future of our species...after all, we haven't been around nearly as long. What if we run up against an innate limit in our brains, and our technology can proceed no further?


I think that it helps illustrate what is actually a non-distinct separation between H. Ergaster (thanks for identifying that) and modern humans.

If it were the case that H. Ergaster simply reached the limits of their mental capacity, we should have seen other examples of tool use. We should be able to find species which developed tools a step or two beyond H. Ergaster. Instead what we see is that there is a type of technological explosion beyond that point.

I would argue that our intellect has reached a sort of 'critical mass' with regard to its capacity to manufacture tools of increasing complexity and advancement. While we may reach plateaus, our intellect allows us to circumvent artificial limits and develop new technologies. Even now, we are inventing tools that help us create tools that are beyond our physical limitations (CAD, genetic simulations, etc).

In contrast, H. Ergaster invented and used the stone axe, and almost a half million years later was still using the same stone axe. In a similar amount of time, modern humans have progressed from the stone axe, to sending robotic explorers to other planets.

Not so Rare Earth

[sgbett]

Interesting, considering that just last night I was watching a documentary, on BBC4 no less, about rare earth theory and how miraculous it was that the conditions on earth are as they are.

Funny but, I couldn't shake the feeling that the reason conditions here on earth are so 'perfect' for life as we know it was more to do with life as we know it evolving to fit the conditions ...

Re:Aquatic life?

[TripMaster Monkey]

Wouldn't it be feasible that intelligent life could arise on a planet that is liquid?

Our own earthly cephalopods are pretty darned smart. Given the right conditions, it's not difficult to imagine a similar species attaining greater intelligence. Of course, such an intelligence, having developed in such an alien environment, would be radically different from ours. As Larry Niven says, there are brains out there that think just as well as yours...but differently.

Also, although an aquatic species could conceivably develop intelligence, I can't imagine what form its technology would take. With such elementary things as fire denied to them, it's doubtful that they could progress to any reasonable level.

Energy is the issue

[microbox]

The speed of light is not a deal-breaker. It means that, from *our* perspective, we'll send people to distant planets and never hear from them again. But from their perspective, it may be a few years. If interstellar travel actually happens, then the speed of light issue is just a managable logistical issue. It means that space-farers must be able to think for themselves. They already must be self-sufficient in other respects.

If there is a deal-breaker, then it is contruction and propulsion of such a craft. The vaster the craft, then the more unlikely it's construction. We might be able to fire ourselves off in a single direction, but how do we slow down, and what if we need to change course. If we need to come home, then we've doubled the energy required!

Then there are complex issues with people - our fragile minds and bodies. How do we react to the stress of space-travel, can we do it?

The speed of light seems like a comparatively simple issue.

Re: bad guess

[Jeremy_Bee]

I disagree. I understand the argument you are trying to make, but your "1 in a million" suggestions are really more akin to wild stabs at the biggest number you can think of, than they are reasonable guesses. 1:1000000 is really an unusually small ratio, and not as common as you intimate. It certainly has no actual relation to the situations that present themselves in the formula.

You can't simply spout a bunch of hyperbole and expect to be taken seriously. Especially in reply to an article that attempts to actually determine those numbers and percentages based on facts. This kind of talk is really no different from the comedy statement that "90% of people know that you can prove anything with statistics." It's meaningless.

While we will likely have to wait a whole lot longer for meaningful answers to the Drake equation, attempts at putting fact-based numbers on the variables should be applauded, and discounting them with what amounts to emotional hyperbole should be discouraged IMO.

Re:Aquatic life?

[rijrunner]

    Except, we are in the midst of people arguing about exactly how intelligent cephalopods and sea based mammals are.

    The truth of the matter is that we have no real way to gauge the intelligence of other alien life forms. Almost all tests are based on a set of assumptions. It is only fairly recently that we have even defined classes of intelligences within humans (Linguistic, Spatial, Musical, Body-Kinesthetic, Interpersonal, Intrapersonal, Logical/Mathematical). It is entirely possible that intelligent life could evolve in aquatic environments that score extremely high in multiple categories there and we would have no real way of knowing. We know that there are a number of species that have highly evolved linguistic characteristics. But, what are they saying? Is it "See Spot Run"? Is it something profound? Is it elaborate fart jokes? It is entirely possible that the social structures are subtle enough that we have no means of determining how complex they are. When whale song can be heard from thousands of miles away, how do you determine the society that hears it and responds and the relationship between the one singing and the ones listening?

    Someone once said that either we are alone, or we are not. Either answer is mind boggling.

    My view is that we don't even know if we alone here on Earth, much less the universe.

Re:But do we want them?

[Chemisor]

> (Sorry to pick on you but your statments are a bit too Malthusian for the facts.)
> We are going to develop a reliable renewable energy source (probably fusion and solar) before we trully "run out."

And yours are too optimistic. We've been in technological stagnation since 2000 and it's only going to get worse from now on. Research is not a high priority during a depression, and we are definitely heading for one now. I rather doubt we'll have fusion. For one, nobody is seriously working on it. The few projects in existence are just token government efforts "to be doing something". I do not expect them to succeed.

> Plus the mined resources aren't gone...they are in buildings.

Yes, they are. They are also in dirt. The reason we have ore mines is not that iron doesn't exist anywhere else, but that it's concentrated there and is in an easily extractable form. Abandoned skyscrapers will indeed have iron, but at a very low density. Most of it is embedded in concrete as rebar, making it very hard to extract by hand, and impossible to extract on industrial scale. The iron that's out in the open will rust after a few decades of exposure. How long will your house stand if you never fix roof leaks? Once it's rusted, the energy required to extract it becomes enormous. Industrial ores today are sulfides, which are easily melted. Melting rust is very very difficult by comparison.

> they are just harder more expensive to tap.

But that's the whole point. To us they are too expensive to tap now. To a civilization at 12th century level of technology it is impossible to reach at any cost. In fact, even that level requires abundant metal to reach. With all the surface metal gone, civilization might not be able to leave stone age. How will you build a modern mine with a flint axe and a wooden shovel? Or an oil well under the sea? The further you fall, the harder it becomes to climb back. If our civilization falls into stone age, it would quite likely just stay there.

> Actully whe have more proven reserves now than we did 50 years ago,

I would take the official "proven reserves" figures with a very large grain of salt. Some of them are just guesses. Others are outright lies. No, I don't have links, sorry :)

Re:Just because it's rocky

[StikyPad]

most of the extrasolar systems we've found also tend to have Jupiter-like and larger planets and that in the majority of cases, these planets are either fairly close to their stars or in highly eccentric orbits.

That's not an attribute of solar systems in general; it's an attribute of solar systems *we can detect* by viewing perturbations in a star's relative position. There's a reason the first planets have had extremely short orbits and extremely large mass. By virtue of the methodology, the larger the planet and the closer the orbit (which makes for a larger/faster wobble, respectively), the easier we can detect them. A planet with the mass of our Sun would still take centuries to detect with current technology if it had the orbital period of Pluto.

Granted, you qualified your statement, but then you went on to describe the likelihood of an Earth-like planet based on our limited findings. That's a bit like saying "The faintest stars we can see with the naked eye are magnitude 4, therefore it's unlikely that many stars are dimmer than that."