I find it mildly irritating when people argue, if ET is out there, how come we haven't heard them with our radio telescopes yet. So I thought I might try and put it all in perspective for you so you might understand why it is so quiet round here on SETI.
OK These figures are just ballparks and meant to illustrate a point only (Be gentle Dr Wu
)
The known Universe is about 91 Billion Light years across.
So lets for argument sake take the distance from the top of the African Continent (Tunis in Tunesia) as one side
And Cape Town down the bottom as the other side of the known universe. That's about 10,000km
OK some ballpark numbers to consider...
Capetown to Tunis ------- 10,000km
Size uo the known observable universe 91 billion light years across (28x10 to the 9 parsecs)
1 parsec = 3.26 light years
So the visible universe is about 86.3576 x 10 to the 22 km across
That's 863576000000000000000000 km
OK So another approximation...
I know there were experiments before, but lets call Marconi's transatlantic Transmission in December 12 1901 the first successful signal
I will round it to 1902.
That means if Marconi was sitting on one edge of the known universe (Cape Town) Bottom of Africa
And the Other side of the known universe was Tunis in Tunisia
Marconi's signals are now only 12.6mm from Capetown
If we had a civilization transmitting Radio waves for 1000 year, its signal is only 109 mm from Cape town
If we had a civilization transmitting Radio waves for 1 million year, its signal is only 1.09 m from Cape town
So assuming a civilization may go for 1000 year without either blowing itself up, or finding some medium better than radio
We are looking for blobs of radio 100 mm long coming from all different directions up down left right etc that are travelling at the speed of light
While standing in the middle of the African continent.
So we have to be looking in exactly the right direction, at exactly the right time, and have a blob of radio waves 100 mm long land on our dish, that was sent sometime in the last 13.5 billion years.
That is why SETI radios listen mostly to the top 100 songs of the year and not ET
OK, Wu, time to flame me
OK These figures are just ballparks and meant to illustrate a point only (Be gentle Dr Wu
)The known Universe is about 91 Billion Light years across.
So lets for argument sake take the distance from the top of the African Continent (Tunis in Tunesia) as one side
And Cape Town down the bottom as the other side of the known universe. That's about 10,000km
OK some ballpark numbers to consider...
Capetown to Tunis ------- 10,000km
Size uo the known observable universe 91 billion light years across (28x10 to the 9 parsecs)
1 parsec = 3.26 light years
So the visible universe is about 86.3576 x 10 to the 22 km across
That's 863576000000000000000000 km
OK So another approximation...
I know there were experiments before, but lets call Marconi's transatlantic Transmission in December 12 1901 the first successful signal
I will round it to 1902.
That means if Marconi was sitting on one edge of the known universe (Cape Town) Bottom of Africa
And the Other side of the known universe was Tunis in Tunisia
Marconi's signals are now only 12.6mm from Capetown
If we had a civilization transmitting Radio waves for 1000 year, its signal is only 109 mm from Cape town
If we had a civilization transmitting Radio waves for 1 million year, its signal is only 1.09 m from Cape town
So assuming a civilization may go for 1000 year without either blowing itself up, or finding some medium better than radio
We are looking for blobs of radio 100 mm long coming from all different directions up down left right etc that are travelling at the speed of light
While standing in the middle of the African continent.
So we have to be looking in exactly the right direction, at exactly the right time, and have a blob of radio waves 100 mm long land on our dish, that was sent sometime in the last 13.5 billion years.
That is why SETI radios listen mostly to the top 100 songs of the year and not ET
OK, Wu, time to flame me
