A question

[xnamkrad]

Having a discussion here and maybe one of you could help

Comments

[redefining_self]

As long as the signal was detectable over a period of time (maybe a couple of days or so, I don't know how tight the tolerances are on the math) the change on the earth's position would give scientists two separate, presumably intersecting lines pointing to the source that would allow us to estimate distance.

Then the process would begin to identify stars within a reasonable margin of error that might accommodate the signal source.

[xnamkrad]

Thanks, thats a good idea and would suit what is in mind

[captainlucy]

One possibility is to make the same assumption that SETI does, and assume that the alien Signal is a "Hello Universe, we're here!" signal which will presumably include one of a number of universal indicators (eg. it's broadcast will include something at the emission frequency of Hydrogen, or one or more of its energy states) which gives us a measurable yardstick. If we then analyse the signal's redshift, we can determine how fast the signal source is moving either towards or away from us, and use this against figures for the expansion of the universe to obtain an approximate figure. Obviously this only works with objects at great distances (probably extra-galactic); for objects closer to us we can analyse the known relative motion of stars and match them to the signal that way.

For much closer objects (within a couple of hundred parsecs), if the signal lasts long enough we can use stellar parallax (the difference in angle of a nearby star to "fixed" distant background stars caused by the orbit of the Earth around the Sun) to gauge

[xnamkrad]

For purposes of the discussion, the second option sounds like the answer for this.

Thanks

[rlane33]

I think they would be able to use the amount of static in the transmition to determine the distance... but may be not

[xnamkrad]

How could they use the static?

[rlane33]

The more distance between objects, the more static. So if they had to work for several hours to clean up the message enough to understand it verse a few minutes, there's obviously more static in the one message.

If they had a control number, like one mile has no static but the moon causes three minutes to clear, they could determine the distance of the message.

Wow, that seems complicated...

[xnamkrad]

But you explain it so well, and an interesting idea

[pgmcc]

I'd opt for checking the post code, or the IP address.

[xnamkrad]

But what if they are as advanced as say An Post and don't need postcodes?