Are We Alone?

[heeyy_joe]

Alone again, naturally.

[GrayHare]

There's probably other intelligence Out There, but perhaps their yardstick of minimum intelligence is the discovery/invention of faster-than-light communication. Unless/until a planet's life can tune into the FTL channel, they figure no one's living there worth texting with.

[REWahoo]

Perhaps the yardstick isn't technology at all. With all the things I see on the daily news can we really consider ourselves to be 'intelligent life'?

[Skyward1]

Given the known numbers someone once said it is a statistical impossibility and I tend to agree.

[ChainsBeGone]

If there is intelligent life out there, I hope it ignores us. When civilizations met here on Earth, the more advanced civilization almost always subsumed or destroyed the less advanced civilization. I'm pretty sure we'd be on the losing end of any Close Encounter.

[dmpi]

I agree with the OP assertion that science has got ahead of itself in the area of indirect observations implying with high probability or certainty the existence of remote planets. I would feel a lot better if we have actually optically imaged a few planets and that data matches or correlates to what we would expect through indirection observation.

[M Paquette]

Quote:

Originally Posted by dmpi I agree with the OP assertion that science has got ahead of itself in the area of indirect observations implying with high probability or certainty the existence of remote planets. I would feel a lot better if we have actually optically imaged a few planets and that data matches or correlates to what we would expect through indirection observation.

OK.

The Atacama Large Millimeter/submillimeter Array (ALMA) has just started making observations in its newest, most powerful mode. This shows images in the high microwave spectrum. When aimed at HL Tauri, a young star 450 light years out, it clearly resolved the bands in the disc of material surrounding the star that will eventually become planets.



This was done at a resolution of 35 milliarcseconds, similar to the optical resolution of the Hubble orbital telescope.

The European Extremely Large Telescope (E-ELT), currently starting construction with a planned first light in 2024, will be able to resolve down to 1 milliarcsecond (depending on the instrument in use). This should be sufficient to directly image the larger planets (Jupiter to Neptune-like) and may be able to probe their atmospheres via low resolution spectroscopy.

The Webb space telescope planned for launch in 2018 may also be able to measure the atmospheres of the largest extrasolar worlds.

The first planned telescope that may be able to look for the signature of life on extrasolar worlds is the Advanced Technology Large Aperture Space Telescope (ATLAST), a NASA 'strategic mission concept study' that, if funded, might fly in the 2025-2035 period. The resolution of this proposed device is 5-10 times that of the Webb space telescope, and a sensitivity limit up to 2,000 times that of the Hubble.

ATLAST is probably the smallest, earliest telescope to meet your optical imaging requirement.

[growing_older]

Quote:

some years ago where they were going to put a Space Camera out beyond the orbit of Jupiter or Saturn in an effort to be able to observe Planets around Stars.

So what's the purpose of that? Nearest possible useful planet we may have detected at Alpha Centari is over 4 light years away (and the next nearest over 11 light years). That means moving our observation post past Saturn would be between a whopping 0.0033% closer to the target to 0.0013% closer. Hard to see how that tiny difference could help with resolving any image.

[M Paquette]

Quote:

Originally Posted by growing_older So what's the purpose of that? Nearest possible useful planet we may have detected at Alpha Centari is over 4 light years away (and the next nearest over 11 light years). That means moving our observation post past Saturn would be between a whopping 0.0033% closer to the target to 0.0013% closer. Hard to see how that tiny difference could help with resolving any image.

It's not the distance. It's the aperture. Placing multiple telescopes separated by distance and carefully synchronized produces a 'synthetic aperture' or resolving power similar to a single telescope with an aperture the size of the space between the two smaller telescopes. This has been done on earth for both optical and radio telescopes.

With multiple instruments in solar orbit, we can produce a synthetic aperture hundreds of millions of miles across. This is currently in the 'really neat research project' phase.

[Telly]

My opinion is that we ARE alone. It was all a mistake, a terrible mistake...

[Ed_The_Gypsy]

A little Googling gave some interesting results.

There are roughly 100 to 200 billion (100,000,000,000 to 200,000,000,000) galaxies in the VISIBLE universe (where it stops is debatable). We know there is ONE inhabited planet in our galaxy. With that ratio, there are a LOT of them.

There are several estimates for the Milky Way. One is 50 million habitable planets . How many have a) life, b) intelligent life? Good question. If only 1/1 million (my WAG), that is 50. The Milky Way is about 100,000 light years in diameter. The average distance to such a planet would be about 2,000 light years. This is starting to look like we might be able to verify the existence of any neighbors!

98% of all the G2 stars in the universe are older than our sun. Our youthful sun and solar system are the beneficiaries of increasing amounts of elements formed by fusion and fission that are not prevalent in older stars. Let's say that is a requirement for life and later, intelligent life. By orders of magnitude, that brings us back to about 1 of us in a galaxy at this time.

How about a window in time? The universe is about 13.7 billion years old. The Milky Way is about 10 to 13.6 billion years old. The solar system and the Earth are about 4.5 billion years old. Life is about 3.5 billion years old. Man of one sort or another is 2.4 to 7 million years old. Homo Sapiens seems to be about 0.16 to 0.4 million years old. Homo Sapiens went through a genetic bottleneck about 70,000 years ago that left only about 2,000 to 10,000 individuals alive. The last ice age ended about 11,500 years ago and ever since we have been on a real tear! Culture is known to be at least 7,000 years old. Since the last ice age we have taken over the planet from pole to pole. Our population really took off about 1000 BC and then again in about 1940. The Industrial Revolution started in 1790, only 224 years ago. This is the blink of an eye. The way we are going, I don't think the planet will be able to support the population in a couple of hundred years and I would not bet on the survival of the human race for more than another 1,000 years. Based on these wild conjectures, I figure there is roughly a 1,000 year window in time in the life of a solar system when a sufficiently advanced technological society can send or detect communications from Outside. So...maybe, maybe not.

How about leaving our/their planet? The universe beyond the Earth's magnetosphere is pretty hostile to organic life, and the higher the form, the more delicate it is. As it is, transcontinental airline pilots get a hell of a lot more exposure to cosmic rays than bus drivers and astronauts have commonly experienced flashes in their eyes caused by Cherenkov radiation. Mutating like the Fantastic Four in a cosmic ray storm IS fantastic. On long trips, astronauts may be killed outright or be young victims of cancer. So, I doubt that us or them will be doing much interstellar travel in our corporeal forms. Don't bet on FTL travel, either.

Just my random thoughts and opinions.

Gypsy

[Ed_The_Gypsy]

Quote:

Originally Posted by 6miths So many great quotes on the topic. "I think the surest sign that there is intelligent life out there in the universe is that none of it has tried to contact us." Calvin of 'Calvin & Hobbes'

+!

[growing_older]

Quote:

It's not the distance. It's the aperture.

Ah ha. That wasn't clear from the comment about sending out a camera. Thanks.

[Lucantes]

I would be very surprised if we were the only intelligent life form to have ever existed in the entire universe, just because the universe is a really big place full of really neat and cool stuff happening all the time.
Now because the universe is a really big place, we may never actually contact any of these other intelligent life forms....but that doesn't mean they don't, or didn't or won't, exist.

[UnrealizedPotential]

Quote:

Originally Posted by growing_older So what's the purpose of that? Nearest possible useful planet we may have detected at Alpha Centari is over 4 light years away (and the next nearest over 11 light years). That means moving our observation post past Saturn would be between a whopping 0.0033% closer to the target to 0.0013% closer. Hard to see how that tiny difference could help with resolving any image.

I think the purpose of it would be to get far enough away from the Sun to minimize as much as possible the Star light from the Sun.The light from the Sun would still be intense but it wouldn't be as strong and we would be better able to block out the Sunlight and have a better chance at observing distant Worlds.I think on the back side of the Camera there would be some kind of a shield to help block out the light from the Sun.I have no idea if we could photograph Planets from such a Camera but we almost certainly would stand a much better chance than anything we have done thus far.

[donheff]

Quote:

Originally Posted by LOL! Even with trillions and trillions of planets out there, the probability of intelligent life would be infinitesimally small, such that it might exist on only one planet among all of them at any given moment in time. Since one such planet exists now, there is probably not another one at this moment in time. I think we have to assume that chemistry is what it is and physics is what it is. When one does that, then one realizes how special life is and how very very special intelligent life is.

From what I have read this argument applies to our universe with it's finely tuned laws compatable with life (massively unlikely to exist but we are here so obviously it does). But, once this unlikely universe exists, there is no reason that life itself would only evolve in one place. We know there are as many galaxies as stars in our own all subject to the same physical laws, and we don't know whether the observable universe is all there is or a fraction of it. The opportunities for life are virtually endless. What we can intuit is that there are not vast numbers of intelligent beings flitting from system to system visiting virtually every place in existence or we would see some evidence. But the universe is an unfathomably big place so that doesn't mean we are alone. Maybe the speed of light is a real limit and wormholes a fantasy. Maybe intelligence is thinly spread so the likelihood of contact is vanishingly small. Or maybe we are a unique creation 6000 years old and a God is just F'ing with us by providing evidence to the contrary.

[Totoro]

My view:

• Depending on how one defines life, we are most likely not 'alone'
• Barring ways to get past the speed of light limit, we won't find life similar to our intelligence level

First one is getting less controversial with the discovery that most stars have rocky planets, water (ice and liquid) is quite abundant and our sun is not that remarkable. Ed the Gypsy sums up the numbers quite well. Even Europa might contain life, and that's in our own solar system no less.

The second one mainly comes from the observations that

• Life in another galaxy is too far away for anything practical. The nearest satellite (dwarf) galaxy is 2.500 light years away. The andromeda galaxy is 2.5 million light years away. Think about this in context of the Voyager: after nearly 40 years it has barely left our solar system, and it took advantage of a huge gravitational boost to accelerate pretty hard.
• So this narrows the realistic options for detection to the 11 billion or so estimated earth-like planets with a sun roughly similar to our own. Unfortunately quite a lot of them get sterilized or vaporized quite quickly due to gamma ray bursts or other catastrophic events. Our sun is in a quiet neighorhood (lucky us). Still, even at a number of say a few million candidates we will still have company. With some luck we'll able to detect signals of life through emissions.
• Now, establishing whether something is intelligent life is another ball game. To do that, practically speaking, we'll only have our own neighborhood accessible to us. Within the nearest 16 lightyears we have a total of 56 stars. That's 32 years to get a "hello, how are you - fine" thing going. And then you still run into the following issue:
• Of the millions of species on earth we are barely able to communicate on a meaningful level with a handful of them, most of them are mammals (and a few birds). Most we classify as "non-intelligent", none of them we place as on par with ourselves. Other life forms will therefore likely appear non-intelligent to us as well (even if they might be more intelligent!) unless they are in a very narrow band of parameters.

Would love to be proven wrong though in my own lifetime but the odds don't seem to be in our favor.

[mystang52]

Quote:

Originally Posted by UnrealizedPotential Detecting Planets by indirect methods IMO leaves alot of room for doubt and speculation.I am not saying the information is not correct,however if we could observe the Planet that would remove all doubt.So with all due respect I still have doubts .

"I agree with the OP assertion that science has got ahead of itself in the area of indirect observations implying with high probability or certainty the existence of remote planets. I would feel a lot better if we have actually optically imaged a few planets and that data matches or correlates to what we would expect through indirection observation. "

Here's direct image of 3 exoplanets; just points of light but nevertheless interesting:
First 'bona fide' direct images of exoplanets - physicsworld.com

[Brett_Cameron]

Quote:

Originally Posted by mystang52 " " Here's direct image of 3 exoplanets; just points of light but nevertheless interesting: First 'bona fide' direct images of exoplanets - physicsworld.com

Nice pictures. Thanks for the link.

[robnplunder]

Quote:

Originally Posted by 6miths So many great quotes on the topic. "I think the surest sign that there is intelligent life out there in the universe is that none of it has tried to contact us." Calvin of 'Calvin & Hobbes'

I love the quote.

Given so many galaxies out there, I say we are not alone. We are just too far apart to kill (conquer) each other. We consider ourselves intelligent and see how much killings we do among ourselves, against other species, and to ourselves.