Worm Hole light years away and look at Earth through a giant telescope

[Dnj23]

Summary: I'd like to know if anyone else thinks of these things

<mentor moved to general discussion>[/color]
What if one day we can "warp" x light years away from Earth, build an enormous telescope, and look back at the Earth x years ago with resolution that rivals the American flag on the moon?

Do you think one day that will be possible?

 

[phinds]

Summary: I'd like to know if anyone else thinks of these things

What if one day we can "warp" x light years away from Earth, build an enormous telescope, and look back at the Earth x years ago with resolution that rivals the American flag on the moon?

Do you think one day that will be possible?

No

 

[Dnj23]

No

Lol.

But, you understand the implications of this? You could theoretically observe Earth's past at any point in time.

 

[Vanadium 50]

But, you understand the implications of this? You could theoretically observe Earth's past at any point in time.

Does wanting something to be true affect its probability of being true?

 

[phinds]

Lol.

But, you understand the implications of this? You could theoretically observe Earth's past at any point in time.

Yes, and we could theoretically observe beautiful pink unicorns (if they existed). I'd really like for that to be true, so I'm going with it, based on your logic.

 

[Dnj23]

Does wanting something to be true affect its probability of being true?

Possibly.

The dreams and passions of people achieving the impossible has occurred in history.

 

[Dnj23]

Yes, and we could theoretically observe beautiful pink unicorns (if they existed). I'd really like for that to be true, so I'm going with it, based on your logic.

It's the worm holes that's bothering you?

 

[weirdoguy]

The dreams and passions of people achieving the impossible has occurred in history.

If by "impossible" you mean things that are against well established science, then no, it has not occurred.

 

[davenn]

Possibly.

The dreams and passions of people achieving the impossible has occurred in history.

Rubbish

The discovery of previously unknown science/physics is not the same as being able to do the "impossible"

New science understanding occurs and is done all the time, doing the impossible , isn't

 

[PeroK]

Possibly.

The dreams and passions of people achieving the impossible has occurred in history.

This is explicitly a forum to discuss established science. It's not a forum, thank goodness, to discuss science fantasy. Or to discuss your dreams and passions.

Although you may feel we don't take your question seriously it's important to ignore questions like yours in order to stop this forum degenerating. There are many places on line where you can discuss this stuff at great length. But PF isn't one of them.

 

[Dnj23]

This is explicitly a forum to discuss established science. It's not a forum, thank goodness, to discuss science fantasy. Or to discuss your dreams and passions.

Although you may feel we don't take your question seriously it's important to ignore questions like yours in order to stop this forum degenerating. There are many places on line where you can discuss this stuff at great length. But PF isn't one of them.

You guys are being a bit condescending. My intentions are not to degenerate this forum, it was sincere. I probably don't have your educational background or experience with these type of topics. So please excuse me.

 

[phinds]

You guys are being a bit condescending. My intentions are not to degenerate this forum, it was sincere. I probably don't have your educational background or experience with these type of topics. So please excuse me.

There is absolutely no condescension in that response. You need to read it as a simple statement of fact without the attitude. Internet forums easily degenerate into junk. The moderator's job is to prevent that happening here and most members who have been around for any time join in that effort because we whole-heartedly embrace it.

 

[Dnj23]

There is absolutely no condescension in that response. You need to read it as a simple statement of fact without the attitude.

 

[DaveC426913]

Summary: I'd like to know if anyone else thinks of these things

Yes. Others have considered the idea.

What if one day we can "warp" x light years away from Earth, build an enormous telescope, and look back at the Earth x years ago with resolution that rivals the American flag on the moon?

Do you think one day that will be possible?

Warp drive aside, the problem is that light leaving the Earth dims as the inverse square.

Were you to zoom out to one light year in your spaceship, the number of photons available to your telescope will be so few that any image would be too dim and without enough detail to see much except a fuzzy ball that is Earth.

And that's only "looking back" one year. Zoom out to ten light years, and you're now receiving only 1/100th of the photons. Dimmer, fuzzier image.

Zoom out to 100 light years, and Earth is now only 1/10,000th as bright. You get the idea.

 

[Drakkith]

If we put aside the idea of superluminal travel, this idea becomes far more reasonable to discuss. In such a case you're limited by two things, both of which DaveC touched on in the post above.

1. Resolution
2. Brightness

The brightness is directly related to the number of photons you can gather over time, and scales as 1/r² (double the distance, cut the brightness to a quarter). The resolution is related to the angular size of the object, which scales linearly (double the distance, halve the angular size).

At multi-lightyear distances, both the brightness and angular size of the Earth are extremely small, and you'd need an absolutely massive telescope to gather enough light, in a short enough time, and with enough detail. You can't even do the usual method of taking many shorter exposures and stacking them together to generate the equivalent of one long exposure, as the rotation of the Earth would cause some parts of the Earth to rotate into and out of view over time.

 

[pinball1970]

Summary: I'd like to know if anyone else thinks of these things

What if one day we can "warp" x light years away from Earth, build an enormous telescope, and look back at the Earth x years ago with resolution that rivals the American flag on the moon?

Do you think one day that will be possible?

For a real comparison, if you look at Hubble images of galaxies you can see the sort of resolution you get when the distances are large.These are galaxies remember, some a hundred (EDIT thousand) light years across, you can make out shape, colour and size but that’s about it.The JWST will be able to “look” further and with greater detail than Hubble and will probably be able to see the flags on the moon, but this is the moon, a stone’s throw.As a slight aside this is LROC is and only a 100km orbit or so from the moon’s surface

http://www.lroc.asu.edu/featured_sites/

 

[DaveC426913]

These are galaxies remember, some a hundred light years across...

??

 

[diogenesNY]

Some will fit right in your pocket... just check out any search engine :)

Seriously, the Milky Way is (casually) maybe 100,000 ly across... maybe more like 140,000 if you prefer certain other definitions. Not an expert, YMMV.

Galaxies like Hercules A and M87 are considerably larger.

references available if required

diogenesNY

P.S. Here is a fun link:

http://www.rhysy.net/galaxy-sizes.html

 

[pinball1970]

??

100,000!

 

[pinball1970]

Some will fit right in your pocket... just check out any search engine :)

Seriously, the Milky Way is (casually) maybe 100,000 ly across... maybe more like 140,000 if you prefer certain other definitions. Not an expert, YMMV.

Galaxies like Hercules A and M87 are considerably larger.

references available if required

diogenesNY

P.S. Here is a fun link:

http://www.rhysy.net/galaxy-sizes.html

It was a typo I promise!
Perhaps I should have stuck to very big but very far away.

 

[sophiecentaur]

You guys are being a bit condescending. My intentions are not to degenerate this forum, it was sincere. I probably don't have your educational background or experience with these type of topics. So please excuse me.

I can appreciate that you may feel slightly piqued by the PF response but that's only following our basic rules. One of the main purposes of PF is to promote the 'understanding' of accepted, mainstream Physics (Science). PF does its best to ensure that a serious enquiry about that (arguably) limited range will get a reliable response and possibly some suggestions for further legitimate study.
There are so many other forums that have the extreme opposite approach that one can always find a non-boring, non-sensible response to any off the wall idea by just going a little way down the road. Problem: could you believe in any of the answers you get?

 

[pinball1970]

Being wrong and finding out about it is extremely important, it means you have ruled something out that was incorrect, embrace it.
Lawrence Krauss summed it up in this way, (paraphrase)' I come to work every single day and I am wrong about things. This is important, it's called learning.'

 

[TeethWhitener]

At multi-lightyear distances, both the brightness and angular size of the Earth are extremely small, and you'd need an absolutely massive telescope to gather enough light, in a short enough time, and with enough detail.

This is a fun little exercise. Given a blackbody temperature of the Earth of ~300K and the Earth's radius expressed in light years, you can calculate the number of photons from the Earth impinging on a 1m² telescope mirror per second at different distances. I calculate that at 100 light years, you get about 2 photons per second from the Earth. At 1 million light years, this becomes about 5-6 photons per year.

 

[DaveC426913]

This is a fun little exercise. Given a blackbody temperature of the Earth of ~300K and the Earth's radius expressed in light years, you can calculate the number of photons from the Earth impinging on a 1m² telescope mirror per second at different distances. I calculate that at 100 light years, you get about 2 photons per second from the Earth. At 1 million light years, this becomes about 5-6 photons per year.

Putting numbers to it. That's awesome.

 

[davenn]

These are galaxies remember, some a hundred (EDIT thousand) light years across,

... many much bigger 100,000 ly and bigger

 

[phinds]

... many much bigger 100,000 ly and bigger

Here's one with a 4 million light year diameter

 

[sophiecentaur]

This is a fun little exercise. Given a blackbody temperature of the Earth of ~300K and the Earth's radius expressed in light years, you can calculate the number of photons from the Earth impinging on a 1m² telescope mirror per second at different distances. I calculate that at 100 light years, you get about 2 photons per second from the Earth. At 1 million light years, this becomes about 5-6 photons per year.

We're going to need a bigger telescope.
My little 10 inch Newtonian is so insignificant.
Otoh, we can see (with the naked eye on a reasoable night) the andromeda Galaxy that clocks in at a mere 2.5 MLY.

 

[phinds]

We're going to need a bigger telescope.

Thanks for the chuckle. Never has that paraphrase seemed more appropriate.

 

[Drakkith]

This is a fun little exercise. Given a blackbody temperature of the Earth of ~300K and the Earth's radius expressed in light years, you can calculate the number of photons from the Earth impinging on a 1m² telescope mirror per second at different distances. I calculate that at 100 light years, you get about 2 photons per second from the Earth. At 1 million light years, this becomes about 5-6 photons per year.

Hmmm. I wonder how much reflected sunlight you'd collect at those distances.

 

[TeethWhitener]

Hmmm. I wonder how much reflected sunlight you'd collect at those distances.

With an Earth albedo of 0.3 in full sunlight, I get a photon per m² (from the sun, reflected off earth) every 10 seconds or so at 100 light years. These are really crude approximations, though, so don't start building that telescope just yet.