Are We Alone?

[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]

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]

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]

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]

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]

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]

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]

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]

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]

" "

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]

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.

 

[nuke_diver]

"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

A few more ...somewhat more recent than that article

List of directly imaged planets

So really we haven't got ahead of ourselves, there are a LOT of planets and therefore a lot of opportunity for life and intelligent life. I think we will find evidence of extraterrestrial life (maybe on Mars maybe elsewhere) but intelligence will be much tougher. We have only been communicating by radio for a little more than a century. If in say another century we find a better way our radio signals will stop. Those signals also get weaker and weaker with distance so they become harder to detect out of the background noise. So IMO unless you can physically go to the planets to check them out (ie some kind of warp drive that doesn't exist) it will be almost impossible to detect an intelligence unless they are very close <50 light years maybe closer.

I personally think it is arrogant to believe that we are the only ones but I also think it is a very hard thing to find/detect given the vastness of space. Also if the intelligence communicates in a manner than we never considered (say flashes of light ie cuttlefish) we will never detect them

 

[robnplunder]

SETI should be stopped just in case .... ;-)

 

[Fermion]

Of course there are other lifeforms out there. The math says it would be more likely to win powerball three times in a row than be alone in the universe.

(edit: I did sort of make up that statistic, but it is estimated there are at least 100 billion galaxies in our universe, some containing over a trillion stars. When you start working with figures of 100 billion trillion, even long odds become pretty good.)

The math also says it is likely we are too far away to ever contact another world species, certainly to establish 2-way conversation over any realistic timeframe.

Of course I also believe that in one of the infinite universes that has been or will be, I was alive when we did establish contact with an alien species. Perhaps this particular universe and time is that one.

 

[Bikerdude]

If you have doubts you must have never seen this:

 

[robnplunder]

One only needs to watch Ancient Aliens program on history channel. Every ancient mystery or feat is connected to aliens and/or their technology. Apparently, earth is a magnet for benevolent aliens. Tongue firmly in cheek.

 

[Gumby]

Seems an appropriate opportunity to post this "Pale Blue Dot":

 

[Gumby]

And, more directly related to the OP, here is some reading about the Drake Equation, which tries to estimate the probability that we might eventually contact an intelligent life form.

Drake equation

 

[ejman]

It is difficult for us to understand that the distances between starts and Galaxies are so vast and beyond normal human experience that even in the imaginary realms of Star Trek faster than light travel it would take 75 years to travel back from the other end of our Galaxy - about 75,000 light years. So even at "Warp 9.9" they make only about 1,000 light years per year i.e. it takes one day to travel 2.75 light years. At that rate, it takes 2,538 years to travel to our nearest neighbor galaxy - Andromeda.

My personal belief is that the universe is teeming with life and that there are many many intelligent beings throughout our galaxy and universe. I also believe that the speed of light is an absolute physical limit (unlike say the speed of sound) so that we will effectively remain isolated forever. The physical resources required for interstellar travel at sub light speeds are just so massive that no planetary society would dedicate a majority of its output to such an endeavor just for the fun of it.

Worm holes are fun to think and read about but there is absolutely no physical real evidence for such.

 

[mystang52]

I love this subject matter, and I suspect this thread will have its own long lifespan.
As to intelligent life developing elsewhere (forgetting for now any ability to detect them): The universe, and our own solar system, is one heckuva dangerous place. Planetary collisions, large meteors and comets [think: the one that killed the dinosaurs], coronal mass ejections, etc etc all make things quite difficult for complex life forms to develop. Many exoplanetary systems are not conducive to advanced life, at least in part due to Jupiter-like planets in orbits that disturb the orbits of the other planets. Our solar system is relatively stable, which allowed Earth to survive and thus provide the time needed to let humans evolve. And then, throw in our Moon, which stabilizes Earth's rotation. All in all, many "lucky" events needed for intelligent civilizations.

 

[6miths]

To quote the late Michael Crichton, "Life finds a way."