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Gold Barz
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Is 10K reasonable?
Gold Barz said:Is 10K reasonable?
Gold Barz said:Heres another question, can we detect radio waves clearly 1000 light years away?
Maybe - if they were transmitting enough...Gold Barz said:Could we detect a technological species 1000 light years away
No, it isn't safe to say that: We're not looking at the entire sky with radio telescopes all the time and random broadcasts would have to be extremely powerful for us to pick up at that distance....since we haven't yet...is it safe to say there are no technological species 1000 from us?
Gold Barz said:Could we detect a technological species 1000 light years away, since we haven't yet...is it safe to say there are no technological species 1000 from us?
plum said:Why would the broadcasts have to be powerful? They would have to be sent 1000 years ago for a civilization 1000 light years away, but radio waves generally don't become weaker as they travel through space.
russ_watters said:Maybe - if they were transmitting enough... No, it isn't safe to say that: We're not looking at the entire sky with radio telescopes all the time and random broadcasts would have to be extremely powerful for us to pick up at that distance.
You are very preoccupied with this issue...
plum said:If they're older than us, then they are very likely far, far older, meaning that they very likely have discovered a more efficient means of communication than radio.
Gold Barz said:Yes, very..its because on another forum, people are assuming that there are a very low number of technological species just because we haven't detected anything in that 1000+ light-year sphere.
ohwilleke said:On surface of the curved Earth the horizon is on the order of 40-60km (this is what they use for military planning purposes at any rate). On a clear day you can see forever (good movie, not very practical unless you have a Hubble Telescope). The Sun is more than 100 million km (100 Gm) away and you see it every day. The stars you can see with your naked eye on a clear night are in some cases hundreds of thousand or even hundreds of millions of light years away, if not further.
Gold Barz said:Could we detect a technological species 1000 light years away, since we haven't yet...is it safe to say there are no technological species 1000 from us?
ohwilleke said:I know you can see the Milky Way, which got me to 100,000. And, I know that there are galaxies you can see, which got me to a larger number.
I stand corrected on the hundreds of millions figure. This source: http://www.seds.org/messier/m/m033.html puts the most distant at 3 million light years (M33) if your eyes are pretty normal, and 12 million light years (M81) if your eyes are exceptionally sharp. Andromeda would be the third most distant object visible to the naked eye. At least I was only off by about one order of magnitude.
They would lose intensity unless they wee pointed directly at us in an extremely narrow beam (ie, a radio laser). Omnidirectional radiation loses intensity in a distance squared relationship.plum said:Why would the broadcasts have to be powerful? They would have to be sent 1000 years ago for a civilization 1000 light years away, but radio waves generally don't become weaker as they travel through space.
But we haven't, so it wouldn't help us talk to them.If they're older than us, then they are very likely far, far older, meaning that they very likely have discovered a more efficient means of communication than radio.
Or even 100, yes.Gold Barz said:So just because we haven't heard anything or detected anything there still could be a technological civilization within 500-700 light years from ours?
On the Contrary, Electromagnetic waves of all freq. (including Radio waves) undergo Red-Shift as Space expands (however miniscule)..plum said:Why would the broadcasts have to be powerful? They would have to be sent 1000 years ago for a civilization 1000 light years away, but radio waves generally don't become weaker as they travel through space.
Chronos said:The frequency thing is a little dicey, but broadcasting at the 21 cm wavelength would be a no-brainer for any advanced civilization
Yaaks said:On the Contrary, Electromagnetic waves of all freq. (including Radio waves) undergo Red-Shift as Space expands (however miniscule)..
21 cm is the frequency of neutral hydrogen. An advanced civilization would realize broadcasts at this frequency would have an excellent chance of being detected by other radio astronomers - who would naturally spend a lot of time mapping the distribution of neutral hydrogen.Pengwuino said:Whys that?
Well!,, i was refrerring to the Universe as a whole, Generally speaking!...GOD__AM said:There is no red shift due to expansion from our own galaxy.