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Shouldn't we have heard alien radio signals by now? Why not?

by SeventhSigma
Tags: alien, radio, signals
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Orion1
#19
Aug20-11, 02:58 PM
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Most humans underestimate the vastness of space-time.

Watch this video and pay close attention to time index 2:35 to 2:49, the extent of humanity's first radio signals to scale with the Milky Way galaxy. This should provide some indication as to just how difficult it is to detect an artificial transmission, even within our own galaxy, let alone any artificial transmission from another galaxy.

Reference:
The Known Universe by the American Museum of Natural History - YouTube
Ryan_m_b
#20
Aug20-11, 03:13 PM
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Quote Quote by Orion1 View Post


Most humans underestimate the vastness of space-time.

Watch this video and pay close attention to time index 2:35 to 2:49, the extent of humanity's first radio signals to scale with the Milky Way galaxy. This should provide some indication as to just how difficult it is to detect an artificial transmission, even within our own galaxy, let alone any artificial transmission from another galaxy.

Reference:
The Known Universe by the American Museum of Natural History - YouTube
Very cool! Can anybody tell me the reason as to why the areas of the universe we have mapped extend from Earth in a sort of double fan shape rather than a sphere?
Orion1
#21
Aug20-11, 03:39 PM
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Quote Quote by ryan_m_b
Can anybody tell me the reason as to why the areas of the universe we have mapped extend from Earth in a sort of double fan shape rather than a sphere?

Watch the TED lecture by astrophysicist George Smoot. The short answer is that this is the limit of the present galaxy sky survey data which must be mapped and cataloged.

Reference:
George Smoot: The design of the Universe
Ryan_m_b
#22
Aug20-11, 03:58 PM
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Quote Quote by Orion1 View Post

Watch the TED lecture by astrophysicist George Smoot. The short answer is that this is the limit of the present galaxy sky survey data which must be mapped and cataloged.

Reference:
George Smoot: The design of the Universe
Very interesting. Thanks
Drakkith
#23
Aug20-11, 06:31 PM
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Quote Quote by Orion1 View Post

Watch the TED lecture by astrophysicist George Smoot. The short answer is that this is the limit of the present galaxy sky survey data which must be mapped and cataloged.
That was awesome!
Flustered
#24
Jan24-12, 01:46 PM
P: 75
Do all intelligent civilizations evolve like we do? Do they all go through the same technology advances we do? What if another life form, had technology in totally different ways than humans, but they were still type 0 or 1 civilizations like us? Is it possible for life forms on the other side of the universe to have different elements and particles from us? Could their periodical table have more elements?
Flustered
#25
Jan24-12, 02:07 PM
P: 75
Also could someone elaborate on the this question.
I once heard that not every galaxy can even harbor life, my teacher told me that only spiral galaxies can have life. Other galaxies cannot have life because they are not spinning there for new stars are not being born, or something to that extent.
DaveC426913
#26
Jan24-12, 02:18 PM
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Quote Quote by Flustered View Post
Do all intelligent civilizations evolve like we do? Do they all go through the same technology advances we do?
We don't know.

Probably there are some considerable differences, but we kind of assume a certain amount of convergent evolution in both biology and technology. (Not the kind that leads to bipedal axial symmetry, but the kind that leads to physical multi-cellular bodies with sensors, organs and brains, as well as a desire to observe the "thousand point of light" in the night sky.)
Quote Quote by Flustered View Post
Is it possible for life forms on the other side of the universe to have different elements and particles from us?
They might be made of different elements than us, though those elements will still be from our periodic table

Quote Quote by Flustered View Post
Could their periodical table have more elements?
No.

Quote Quote by Flustered View Post
I once heard that not every galaxy can even harbor life, my teacher told me that only spiral galaxies can have life. Other galaxies cannot have life because they are not spinning there for new stars are not being born, or something to that extent.
meh.

There are arguments that they may harbor less life than life as we know it, but it's pretty speculative.
Ryan_m_b
#27
Jan24-12, 02:24 PM
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Quote Quote by Flustered View Post
Do all intelligent civilizations evolve like we do? Do they all go through the same technology advances we do?
Evolutionary processes are the same whether or not it is life in the Earth's oceans or dots on a simulator but that doesn't mean they have to be anything like us physically or socially (beyond the need to be able to reproduce with variation to evolve and have the faculties to innovate and build/use tools).

There's little reason to believe that they will have the same technology though they may develop similar solutions to similar problems. It all depends on what natural and social problems they attempt to overcome, what resources they have to do it and what their psychology and culture permit.

This is speculation (albeit logical) and doesn't really mean much until we have more than one tool-using species that we would judge equivalently intelligent to compare ourselves with.
Flustered
#28
Jan24-12, 02:32 PM
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Quote Quote by Ryan_m_b View Post
Evolutionary processes are the same whether or not it is life in the Earth's oceans or dots on a simulator but that doesn't mean they have to be anything like us physically or socially (beyond the need to be able to reproduce with variation to evolve and have the faculties to innovate and build/use tools).

There's little reason to believe that they will have the same technology though they may develop similar solutions to similar problems. It all depends on what natural and social problems they attempt to overcome, what resources they have to do it and what their psychology and culture permit.

This is speculation (albeit logical) and doesn't really mean much until we have more than one tool-using species that we would judge equivalently intelligent to compare ourselves with.
Is it a given that a type 1 civilization can only get there if math is involved, math is a big part of physics and what not. Is it possible for a civilization to get farther than us without math? Also would they have the same concepts as us? Would they need to use negative numbers like we do? Could they advance farther without language?

Michio Kaku was saying that star wars would be a type 3 civilization, is it even possible for all those different life forms to be living in the same galaxy at the same time and fighting one another. I know it is SCI FY but what are the chances? Also Kaku was talking about civilizations taking all of their power from the stars, how would a civilization begin to take solar power from all the visible stars and use it?
Ryan_m_b
#29
Jan24-12, 02:35 PM
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Quote Quote by Flustered View Post
Is it a given that a type 1 civilization can only get there if math is involved, math is a big part of physics and what not. Is it possible for a civilization to get farther than us without math? Also would they have the same concepts as us? Would they need to use negative numbers like we do? Could they advance farther without language?

Michio Kaku was saying that star wars would be a type 3 civilization, is it even possible for all those different life forms to be living in the same galaxy at the same time and fighting one another. I know it is SCI FY but what are the chances? Also Kaku was talking about civilizations taking all of their power from the stars, how would a civilization begin to take solar power from all the visible stars and use it?
The kardashev scale isn't a scientific proposition, it's an idea that doesn't entirely make much sense. The idea being that type 2s have the capability to build dyson spheres and a type 3 simply does this to all stars in the galaxy, but there is no reason to think that there is an absolute path that a tool-using, sentient race would follow this scale. Regarding mathematics it would be pretty important, you can't produce any good science, economics or even politics without it and it would most likely be similar.
Flustered
#30
Jan24-12, 02:38 PM
P: 75
Off topic//

Our all galaxies the same age? And has any galaxies that we know of, started to "die" or are "dead".
Flustered
#31
Jan24-12, 02:48 PM
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Quote Quote by Orion1 View Post



Watch the TED lecture by astrophysicist George Smoot. The short answer is that this is the limit of the present galaxy sky survey data which must be mapped and cataloged.

Reference:
George Smoot: The design of the Universe
Problems with this video, how can we map 360 degrees the CMB, but not 360 degrees of all the galaxies in the universe?

He also didn't explain what in our galaxy is blocking us from mapping the voids, nor did he explain why telescopes can't do it either.

He also said our galaxy is on the "boonies" not at the CENTER of the universe, he was implying that there is a center of the universe, he said it as clear as day.

In another thread, everyone is saying there is no center, but he said different.
Flustered
#32
Jan24-12, 03:02 PM
P: 75
Is there a connection between the formation of galaxy superclusters, and the human brain cells. They look a lot alike.
DaveC426913
#33
Jan24-12, 03:45 PM
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Quote Quote by Flustered View Post
Off topic//
Our all galaxies the same age? And has any galaxies that we know of, started to "die" or are "dead".
All galaxies are not the same age, no. But galaxies won't really die. Galaxies are just collections of stars. I suppose in principle a galaxy could be composed of nothing but dead stars...

Quote Quote by Flustered View Post
Is there a connection between the formation of galaxy superclusters, and the human brain cells. They look a lot alike.
No. Not in any but the most basic ways in mechanics of shapes. (A bubble and a star are both spherical but only because they are both comprised of competing symmetrical inward and outward forces).
Drakkith
#34
Jan24-12, 08:49 PM
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Quote Quote by Flustered View Post
Problems with this video, how can we map 360 degrees the CMB, but not 360 degrees of all the galaxies in the universe?

He also didn't explain what in our galaxy is blocking us from mapping the voids, nor did he explain why telescopes can't do it either.
The CMB is a much longer wavelength than visible and infrared light and is able to penetrate through large sections of our galaxy to be seen, whereas most of the visible light is blocked by dust. It is also very very smooth and is fairly easy to capture a large portion of the sky. In contrast, the vast majority of galaxies require a very high magnification and multiple hours of exposure time to see properly. This puts constraints on how much we can map with the few telescopes we have that can even see them. As an example, consider the Hubble Deep Field and Hubble Ultra Deep Field images. They requires DAYS of exposure time just to capture a very very small area of the sky.

He also said our galaxy is on the "boonies" not at the CENTER of the universe, he was implying that there is a center of the universe, he said it as clear as day.
If you go to the video again, you can see that he said we were not at the center of our Solar System, Galaxy, and Cluster, not universe.
Wanderlust
#35
Jan25-12, 06:03 PM
P: 7
Several Speculative Scenarios

There are no active civilizations within a few tens of thousands of light years. Active being functional and broadcasting for at least a hundred thousand years time. [radius of the galaxy]

There are no civilizations active within a hundred thousand years in time, don't forget we are separated in time as much as space. There is only a 100,000 year window of detection after a civilizations stops broadcasting in one wavelength

All current active advanced civilizations use different communication systems than we do, perhaps ones we have not thought of. Maybe other frequencies or other ideas we have not tried

We are the first civilization to emerge and activate in the galaxy

We are alone in the galaxy

Communication methods fade into the cosmic background after a distance. (most likely, stuff fades out as distances get larger) You need power to go long.

We are not trying hard enough [money]
epenguin
#36
Jan25-12, 06:15 PM
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Quote Quote by tasp77 View Post
We are first.
Some people (i.e. this astronomer I heard in a meeting about 12 years ago) think we are last - we arrived when the party is nearly over.


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