SETI just got €100mil to look for Aliens

Bongalongherb

Unless one of you out there on this planet can understand what technology an alien civilisation say 1 million or more years ahead of us is using then we're never going to be able to receive or communicate with them or even know they exist using simple radio waves.

Maybe we are using our ancient radio wave technology the wrong way, who says they would be even using any radio source in our measured electromagnetic spectrum ? Could they be using some other kind of signal that is not radio waves at all but something much more advanced. Radio signal transmission that travels at the speed of light is very slow on a galactic term and crude imo.

I'm sure that if an advanced civilisation a million years ahead of us would be using communication technologies we can't even fathom and this is probably why we cannot sense them electronically. I know that the world scientists are looking for planets/civilisations that have the same or near the same technological advancement as us so we can possibly detect them, but say if there is none and they are all thousands or millions of years more advanced and don't use what we understand to be communication sets, they could and possibly are out there but they are so far advanced from us they would seem invisible regarding their technology.

Maybe they communicate through what scientists call Dark Matter of which they think exists but cannot measure it or understand it just yet. Maybe like the way we look at Ethernet connection/direct connection, not wirelessly, this so-called dark matter could be a direct link to everything in the universe but we cannot detect it because it is directly connected of which we have no access to detect and understand just yet?. Crazy universe and anything is possible in the near/far future.

RichardoKhan

Errr should we really be sending out calling cards?
Nothing ive seen yet displayed by nature at large suggests any potential visitors will come in peace? Heard the theory that any civilisation capable of inter stellar travel would have left war & greed behind a long time ago. BUT what if they havent & indeed it powers their colonisation?

Captain Chaos

RichardoKhan wrote: »

Errr should we really be sending out calling cards?
Nothing ive seen yet displayed by nature at large suggests any potential visitors will come in peace? Heard the theory that any civilisation capable of inter stellar travel would have left war & greed behind a long time ago. BUT what if they havent & indeed it powers their colonisation?

Like the Europens conquering the Americas all over again. It never works out well for the less technically advanced side even with the home team advantage.

RichardoKhan

Captain Chaos wrote: »

Like the Europens conquering the Americas all over again. It never works out well for the less technically advanced side even with the home team advantage.

Might wait to see what their Planet/s were like then claim asylum......

_Tombstone_

What might an alien think of human technology?

maninasia

They should know we are here, or at least some of them.

We don't need to worry about sending a signal out, because a more advanced technological civilization can detect us very easily (they certainly don't need to wait for our TV signals etc). And given timescales involved in our evolution...some should certainly know about us already.
Finally them being interested in 'us' rather than the beautiful blue planet Earth and all its billions of species..?

mickmackey1

Yes indeed, Earth has been broadcasting a biological signal for hundreds of millions of years and we could well stick out like a sore thumb in our part of the galaxy. The fact we've sent out a few radio signals over the last century or so is beside the point; it's far too late to considering hiding ourselves from detection.

Keplar240B

biological signal

JJJJNR

The planets, solar systems and therefore all universes are linked like a massive network, its a complete head fcuk.

Thargor

Keplar240B wrote: »

biological signal

The "signal" is just visible light bouncing off our plant and out into space, and yes all some aliens would need is a good enough spectrometer and they'll be able to survey the sky and see which planets have biological life, you can even examine the spectrum for signs of industry. Earth has been broadcasting this signal for billions of years at this stage. We'll soon be scanning the sky with similar technology, we already are its just not sensitive enough yet.

Myrddin

Thargor wrote: »

The "signal" is just visible light bouncing off our plant and out into space, and yes all some aliens would need is a good enough spectrometer and they'll be able to survey the sky and see which planets have biological life, you can even examine the spectrum for signs of industry. Earth has been broadcasting this signal for billions of years at this stage. We'll soon be scanning the sky with similar technology, we already are its just not sensitive enough yet.

Light, being relative though makes this somewhat less exciting no? If an Alien civilization scanned Earth today with a spectrometer, they'd see nothing if they're 100+ light years away. Similarly, we can scan every star in the sky & detect nothing, while entire civilizations may have sprung up over the hundreds or thousands of years that light has been travelling to us

mickmackey1

Myrddin wrote: »

Light, being relative though makes this somewhat less exciting no? If an Alien civilization scanned Earth today with a spectrometer, they'd see nothing if they're 100+ light years away. Similarly, we can scan every star in the sky & detect nothing, while entire civilizations may have sprung up over the hundreds or thousands of years that light has been travelling to us

They would not see technology but they would see vast quantities of oxygen for example. And oxygen, being a very reactive element, is being constantly replenished by, in our case, living organisms. So they would deduce that Earth is, at the very least, worthy of further research.

Yes it takes millions of years for information to travel around the universe, but plenty of stars are billions of years older than the sun, so that shouldn't be a problem.

Thargor

The Fermi Paradox really is baffling when you think of how old the galaxy is at this stage, no signs of anything major in other galaxies either.

mickmackey1

Thargor wrote: »

The Fermi Paradox really is baffling when you think of how old the galaxy is at this stage, no signs of anything major in other galaxies either.

Maybe the 'Paranoid Universe' theory is the best one - even advanced aliens are wary of travelling outside their corner of the galaxy because they might encounter even greater technology. If FTL is impossible, there's just no way of knowing who is the king of the jungle.

Thargor

Yeah but with the sheer size of things there should be a million "Jehovas Witness" type species screaming their location aswell

testaccount123

http://www.independent.co.uk/news/world/forget-water-on-mars-astronomers-may-have-just-found-giant-alien-megastructures-orbiting-a-star-near-a6693886.html

_Tombstone_

Thargor wrote: »

The Fermi Paradox really is baffling when you think of how old the galaxy is at this stage, no signs of anything major in other galaxies either.

A rake of ETs building a dyson sphere just across the way there.

_Tombstone_

Ethics of Alien Contact

Keplar240B

mickmackey1 wrote: »

They would not see technology but they would see vast quantities of oxygen for example. And oxygen, being a very reactive element, is being constantly replenished by, in our case, living organisms. So they would deduce that Earth is, at the very least, worthy of further research.

Yes it takes millions of years for information to travel around the universe, but plenty of stars are billions of years older than the sun, so that shouldn't be a problem.

but how can you detect oxygen from faraway?

Keplar240B

testaccount123 wrote: »

http://www.independent.co.uk/news/world/forget-water-on-mars-astronomers-may-have-just-found-giant-alien-megastructures-orbiting-a-star-near-a6693886.html

There's a more skeptical. Article on time magazine google it .

Interesting , I always wondering why we could not detect megastrucutres if (big if) this is it I guess the answer is we only started and sample size I tiny ,

So there are planets or no planets detected in this system
So the aliens or robots inhabit their structure?

ps200306

Keplar240B wrote: »

but how can you detect oxygen from faraway?

With a spectrograph. We've already started doing this from earth. This is the visible emission spectrum of oxygen:



You're more likely to be seeing the corresponding absorption spectrum, i.e. looking through the atmosphere of a planet at a background star with these frequencies notched out. But it's the same identifiable pattern of lines (even when mixed with others), and totally unique to oxygen.

ps200306

Keplar240B wrote: »

There's a more skeptical. Article on time magazine google it .

Ta. Here is the Time Magazine article.

And here's the preprint of Boyajian et al.'s paper from MNRAS. Technical, but well worth a read.

I don't think Time has interpreted her quite right -- she's not suggesting a comet swarm, but comet fragments from a breakup event ... a bit similar to how Shoemaker-Levy 9 was broken up by tidal forces in Jupiter's gravity back in the 90s. This would give the required signature -- not too clumpy but not too dispersed either -- and without the requirement of an infrared signature. Seems to me that the detected companion star might also be responsible for disrupting comets in KIC 8462852's version of an Oort cloud, so maybe comets in the inner stellar system are more common.

nyarlothothep

Forgive my ignorance but if you angled the Hubble Space Telescope at this would we be able to get a glimpse of massive alien structures that we could reverse engineer/theorise about based on photographic evidence to usher in a new age of interstellar travel?

Keplar240B

nyarlothothep wrote: »

Forgive my ignorance but if you angled the Hubble Space Telescope at this would we be able to get a glimpse of massive alien structures that we could reverse engineer/theorise about based on photographic evidence to usher in a new age of interstellar travel?

The only way to clear up this mystery is to make more observations. Boyajian suggests long-term monitoring from ground-based telescopes to look for a recurrence of the dimming events, and is working with Wright to use a radio telescope to listen in for alien broadcasts leaking from the system.

My money is on comet collisions. But part of me hopes I’m wrong.

http://www.theguardian.com/science/across-the-universe/2015/oct/16/alien-megastructure-could-explain-mysterious-new-kepler-results

ps200306

nyarlothothep wrote: »

Forgive my ignorance but if you angled the Hubble Space Telescope at this would we be able to get a glimpse of massive alien structures that we could reverse engineer/theorise about based on photographic evidence to usher in a new age of interstellar travel?

No. You have to think in terms of angular resolution. When you look at the moon or sun in the sky (assuming you could look without being dazzled) you see a disc about half a degree wide, or 30 arcminutes (one degree is 60 arcminutes). The human eye has a resolution of one arcminute. That's the smallest angle at which you can see any detail. Anything smaller is an unresolvable point.

To take an example, a 10cm wide object would subtend an angle of 1 arcminute at a distance of 350 metre. That's about the size of a human hand. If someone waved at you from a hillside 350 m away, you'd just be able to make out their hand. Somewhat further away, you might still see the person, but you couldn't make out their hands.

It doesn't mean an object smaller than one arcminute is invisible. You could see it if it was bright enough. You could easily see a 10 cm wide lamp from more than 350 m away. If someone passed their hand in front of it you'd see the light dimming, even though you could not resolve either the hand or the lamp. (Galileo tried to measure the speed of light using shuttered lanterns separated by five times that distance).

Unlike the sun and moon, the stars are too far away for us to resolve with our eyes. Not only that, almost all of them are too far away to resolve with even the largest telescopes. The Kepler mission detects planets by seeing the light dimming when the planet goes in front of a star, just like the hand in front of the lamp. As you can guess from the foregoing discussion, it doesn't mean we can "see" the planet in the sense of being able to resolve it.

The Hubble space telescope has an angular resolution about 1,200 times better than the human eye -- about 1/20 arcseconds, where an arcsecond is 1/60 arcminutes. (It's not a coincidence that the Hubble's 2.4 metre mirror has about 1,200 times the diameter of the pupil of your eye).

Based on its stellar type, we think the parent star KIC 8462852 is about 1.6 times the diameter of our Sun. At a distance of 1,480 light years, it would subtend an angle of 3/100,000 arcseconds. That's more than a thousand times too small for Hubble to resolve. And that's the parent star, not the planet, which could be dozens of times smaller again. Based on how long the star was dimmed for, even the hypothetical megastructures are only half the width of the star. So again, they are vastly too small to resolve with any current telescope.

Think of it as NASA's dirty little secret -- even though they've detected thousands of exoplanets, they haven't actually "seen" any of them.

Myrddin

Great explanation, thanks for that It has served to remind me just how far away things are from us here

Maximus Alexander

ps200306 wrote: »

Based on its stellar type, we think the parent star KIC 8462852 is about 1.6 times the diameter of our Sun. At a distance of 1,480 light years, it would subtend an angle of 3/100,000 arcseconds. That's more than a thousand times too small for Hubble to resolve.

So all we need is a space telescope with a 2.4km mirror? Jeez guys, what's the hold up?:D

Myrddin

Maximus Alexander wrote: »

So all we need is a space telescope with a 2.4km mirror? Jeez guys, what's the hold up?:D

Is that what the math says yeah? Crazy stuff, if only!

Maximus Alexander

Myrddin wrote: »

Is that what the math says yeah? Crazy stuff, if only!

Well I'm assuming a linear relationship between aperture and resolution, but in that case, yeah! And then you would only resolve the disk of the star, not the 'structures' or whatever are in orbit. :eek:

ps200306

Maximus Alexander wrote: »

So all we need is a space telescope with a 2.4km mirror? Jeez guys, what's the hold up?:D

Not quite as bad as that. Consider the design of reflecting telescopes -- a Newtonian has a secondary mirror that bounces the light from the primary out the side of the telescope to an eyepiece; a Cassegrain (of which the Hubble is a type) uses the secondary mirror to bounce the light back down through a hole in the primary, to an eyepiece at the end. In both cases there's a hulking great obstruction in the path of the primary mirror, between it and the object being observed.



It turns out that the obscuration of the primary doesn't affect the resolution of the telescope, only it's light-gathering power. In other words, you need a longer exposure to get an image, but the image can be just as sharp. This leads to the possibility that you could break the primary mirror up into pieces and put them in different places, and still get the effective resolution of a telescope the size of the distance between the pieces. The distance is called the effective aperture. (The combined mirror area is the collecting aperture). So really, all we need is two telescopes separated by a distance of 2.4 km.

It's been done with the two Keck telescopes in Hawaii to give an 85 metre aperture with ten times the resolution of the Hubble. (You may be wondering why it's not 30 times or more, since that's the ratio of the apertures. It turns out the resolution is also inversely proportional to the wavelength of light, and the combined Kecks work in the near infrared, at about three times the wavelength of visible light).

Unfortunately, it's not a simple technique. The images from the two (or more) telescopes have to be recombined (or "interfered") at a single eyepiece, and for optical telescopes this means complicated arrangements of light paths between the component scopes. The biggest effective aperture achieved to date is 160 m at an Australian telescope, for a resolution about 70 times that of Hubble. There have been proposals for a space-based system with a 1 micro-arcsecond resolution, and a moon-based one with a 2 km aperture and a resolution of 0.1 micro-arcsecond. That would give us half a million times the resolution of Hubble.

Before we get too excited, even these most extreme resolutions would only allow images of stars like KIC 8462852 a couple of hundred "pixels" across. And planets would still be amorphous blobs. The real advantage would be in astrometry rather than imaging. We'd be able to detect tiny lateral movements of stars. (We can already detect tiny radial movements using Doppler spectroscopy). That would allow the gravitational pull of planets on stars to be detected very precisely, without relying on the rare chance alignments that allow Kepler to detect planets by the transit technique.

Just to round out the discussion of long baseline interferometry: at much longer wavelengths -- microwave and radio wavelengths -- the combining can be done electronically, so the size of the effective aperture is practically unlimited. Radio telescopes have been combined to give effective apertures thousands of miles long. Although the longer wavelength reduces the resolution, it is still possible to achieve micro-arcsecond resolutions. Proposed space-based arrangements would do even better, and this has been tried experimentally. As with optical telescopes, you still need large dishes/mirrors to see faint sources.