Texting the cosmos - hey aliens, yeah you with the planet buster ray - we're here.

[PB666]

http://www.bbc.com/news/science-environment-34211549

Some folks, I don't know, why do you want to blast the cosmos with earthen platitudes?

[GeneralVeers]

Texting the Cosmos - hey, aliens who are part of the Unified Federation and have the cure for cancer - we're here.

If the aliens are playing Kerbal Space Program 2......so much the better! Where can I get a copy?

[Aethon]

METI is not science. It is an attempt to provoke a response from an advanced civilization whose motives and abilities we cannot know. If there are other powerful entities in the universe, they certainly aren't broadcasting obvious signals into space. There must be a reason for this. As the newest born technological baby bunny in the galaxy, it is FOOLISH to shout into the jungle.

[wx7]

I am now awaiting conspiracy theories about that to show up on the interwebs.

[Camacha]

This discussion is well over 100 years too late.

/thread

Oh, and please stop just dropping links. You make a lot of these threads. Please summarize the information you think is relevant and what your take on it is. If you want to start a discussion, please actually start a discussion.

[Aethon]

You could help start it by specifying what you mean by 100 years too late.

This is one of the only things I disagree with a true american hero, Seth Shostak about. That the cat is out of the bag and they know we are here. Yes anyone within 70 lys know there is technological life on Earth, and anyone else worth noting has known for the last 2 billion years that the Earth has life on it, but the nearest ETI is probably around 1000 lys away from us. Our signals haven't arrived there yet, and the Galaxy itself is >100,000 lys across.

http://arxiv.org/ftp/arxiv/papers/1207/1207.5540.pdf

"Earth’s radio leakage comes from many different sources that range from active cellphones to television and radio broadcasts to high-power radars used for astronomy and by the military.3 All of these signals travel through space at the speed of light, so television broad casts that occurred twenty years ago are now twenty light years away from Earth (for comparison,Proxima Centauri, the closest star to the Sun, is 4.2 light years away). Leakage radiation from television transmitters occurs approximately in a sphere surrounding Earth, so that the distance at which Earth’s radio signature can be detected has sometimes been termed the radiosphere. However, radar beams are the strongest radio leakage, and spread into space from Earth like pins on a pincushion, with most of the beams (pins) concentrated in the northern hemisphere. The intensity of signals from Earth decays with distance according to an inverse square law, but prior analyses have shown that these faint signals could still be detected at astronomical distances by a sensitive receiver and a sufficiently large antenna."

Edited September 16, 2015 by Aethon

[Camacha]

You could help start it by specifying what you mean by 100 years too late.

You seem to understand perfectly well, so there is no need for that

This is one of the only things I disagree with a true american hero, Seth Shostak about. That the cat is out of the bag and they know we are here. Yes anyone within 70 lys know there is technological life on Earth, and anyone else worth noting has known for the last 2 billion years that the Earth has life on it, but the nearest ETI is probably around 1000 lys away from us. Our signals haven't arrived there yet, and the Galaxy itself is >100,000 lys across.

Well, the cat is out of the bag, dead or alive. Even if our signals have not reached alien life, there is absolutely nothing within science of even most fiction that we can do about those signals reaching them. Unless you call something like inventing FTL travel, finding the alien inhabited world(s) and wiping out their species before our signals reach them a viable plan, of course

[ChrisSpace]

I say we blast as many signals into space as we can. What's the worst that can happen?

[PB666]

I say we blast as many signals into space as we can. What's the worst that can happen?

oh my, hmmm, miley twerking 1 minute loop forever on all media. broadcast.

[YNM]

I... Guess we don't even need to send anything. They certainly knew that this particular star have planets... If guys want to send anything just send it as long as they don't bill me.

[magnemoe]

You could help start it by specifying what you mean by 100 years too late.

This is one of the only things I disagree with a true american hero, Seth Shostak about. That the cat is out of the bag and they know we are here. Yes anyone within 70 lys know there is technological life on Earth, and anyone else worth noting has known for the last 2 billion years that the Earth has life on it, but the nearest ETI is probably around 1000 lys away from us. Our signals haven't arrived there yet, and the Galaxy itself is >100,000 lys across.

http://arxiv.org/ftp/arxiv/papers/1207/1207.5540.pdf

"Earth’s radio leakage comes from many different sources that range from active cellphones to television and radio broadcasts to high-power radars used for astronomy and by the military.3 All of these signals travel through space at the speed of light, so television broad casts that occurred twenty years ago are now twenty light years away from Earth (for comparison,Proxima Centauri, the closest star to the Sun, is 4.2 light years away). Leakage radiation from television transmitters occurs approximately in a sphere surrounding Earth, so that the distance at which Earth’s radio signature can be detected has sometimes been termed the radiosphere. However, radar beams are the strongest radio leakage, and spread into space from Earth like pins on a pincushion, with most of the beams (pins) concentrated in the northern hemisphere. The intensity of signals from Earth decays with distance according to an inverse square law, but prior analyses have shown that these faint signals could still be detected at astronomical distances by a sensitive receiver and a sufficiently large antenna."

It looks like you can detect TV signals out to 50 lightyears with an 1 km/2 array. This require that you scan earth for an good part of an day and that you have done this the last 40-50 years. High power radars can be detected father away but is much narrower beams, rarely on all the time and they don't carry an signal.

[Scotius]

I say we blast as many signals into space as we can. What's the worst that can happen?

"Stop spamming, you newbz!!!111!1!1"

[PB666]

"Stop spamming, you newbz!!!111!1!1"

When has that reply ever worked?

[KerikBalm]

If there are other powerful entities in the universe, they certainly aren't broadcasting obvious signals into space. There must be a reason for this. As the newest born technological baby bunny in the galaxy, it is FOOLISH to shout into the jungle.

The *if* question should be limited to our own galaxy.

As I've stated many times on other threads, given the speed of light, the reasonable travel speeds that could be achieved with fission/fusion/antimatter propulsion methods (.2c), the size of the galaxy (100,000c) the age of the universe/the galaxy/most stars and planets (a few to 13 billion years), the first species/genus/civilization/robots created by a civilization capable of interstellar travel should be spread all over the galaxy before another emerges.

In the absense of any evidence that such a widespread entity, it is reasonable to suppose that we may have a chance of being the first such entity in our galaxy.

Next is the inverse square law... those TV broadcasts will be undetectable relative to the background signal before too long, even the powerful radars we use.

Even a deliberate message will not reach far (unless very tightly focused, in which case only a few target areas can receive it).

If they are close enough to receive it, probably could already do spectroscopic investigations of Earth's atmosphere and know it has life.

The rapid CO2 rise accompanying civilization, actually started centuries ago.

If they wanted to come check us out, they'd already be here/on the way before we sent any radio message.

I'm not so worried... but on the other hand... why risk it?

[YNM]

I think that, if we think we are "new", they should be around already, because their science instruments would be better than ours. I mean, we even now tries to get spectrograph of alien atmosphere, maybe they can resolve Earth from Sun from >50 ly away by the time we consider making those equipment.

[PB666]

The *if* question should be limited to our own galaxy.

As I've stated many times on other threads, given the speed of light, the reasonable travel speeds that could be achieved with fission/fusion/antimatter propulsion methods (.2c), the size of the galaxy (100,000c) the age of the universe/the galaxy/most stars and planets (a few to 13 billion years), the first species/genus/civilization/robots created by a civilization capable of interstellar travel should be spread all over the galaxy before another emerges.

In the absense of any evidence that such a widespread entity, it is reasonable to suppose that we may have a chance of being the first such entity in our galaxy.

Next is the inverse square law... those TV broadcasts will be undetectable relative to the background signal before too long, even the powerful radars we use.

Even a deliberate message will not reach far (unless very tightly focused, in which case only a few target areas can receive it).

If they are close enough to receive it, probably could already do spectroscopic investigations of Earth's atmosphere and know it has life.

The rapid CO2 rise accompanying civilization, actually started centuries ago.

If they wanted to come check us out, they'd already be here/on the way before we sent any radio message.

I'm not so worried... but on the other hand... why risk it?

CO2 has risen rapidly and fallen before, nothing special there.

Photochemical smog has a unique spectrum, lacking the typical volcanic indicators, but they would have to resolve signals from metropolii.

A very high resolution telescope like that proposed in the other thread could see oblique night lights maybe at a distance of 1/2 of a light year. Yes if we remove structural limits, we could build a scope that could resolve ES planets 100 ly away in a few pixels of detail. But the structural limit comes from holding the extreme ends of a telescope within micrometers of the idea, avoiding segmental flexibility generated by gravitational waves, drag, solar winds, servo motors, etc.

[PB666]

Our non-directional transmissions are easily drowned in universe's RF noise. Directed (to star system) transmission can be detected, and reacted upon.

That's why it's stupid idea.

^^^^^^^^^^^^^^^^^^

[KerikBalm]

CO2 has risen rapidly and fallen before, nothing special there.

Photochemical smog has a unique spectrum, lacking the typical volcanic indicators, but they would have to resolve signals from metropolii.

Rapidly on the Geological timescale... but the rate of increase of CO2 is unprecedented as far as I am aware.

Even so... Earth is no "spring chicken" (indeed <1 billion years from being uninhabitable, 4.5 billion years old out of a 5.5 billion year lifespan) with the massive volcanism that the early Earth had.

A big change happening this late in our history should at least get them curious and wondering what is going on - but yea, I'm not positive that the rate of change we currently see is diagnostic of a civilization

[Aethon]

Our non-directional transmissions are easily drowned in universe's RF noise.

Not necessarily true.

Seth Shostak : https://youtu.be/hM71Gxl2XcM?t=4809

"and it doesn't matter what the distance is, you can always pick them up, if you have a big enough antenna"..

[NFUN]

If the aliens are advanced enough to have FTL travel and planet buster rays, why would they care about us? I'd assume that they'd have better things to do than screw around with random podunk species out of their way, unless, by some amazing coincidence, they were traumatized like the Ur-Quan.

[insert_name]

If they are close enough to receive it, probably could already do spectroscopic investigations of Earth's atmosphere as life.

The rapid CO2 rise accompanying civilization, actually started centuries ago.

If they wanted to come check us out, they'd already be here/on the way before we sent any radio message.

the rise in CO 2 could also be interpreted as an increase in volcanic activity, or a series of comet impacts or other chemical reactions, if they werent watching for very long they might not know the rate at which earths co2 grows naturally, also who says they used fossil fuels