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Milky Way, 12 years, 1250 hours of exposures and 125 x 22 degrees of sky

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Re: Milky Way, 12 years, 1250 hours of exposures and 125 x 22 degrees of sky

#121

Post by divbzero »

ekianjo wrote: post #100
divbzero wrote: post #80

Earlier quoted context omitted.

Then again, this photo mosaic spans just one arm of one galaxy in the visible universe.

We know that life only emerges in very specific conditions, that most planets do not have. We also know that even in very stable Earth, we have had billions and billions of species that developed and disappeared and we now only have a single specie with technological capabilities - and for a very short time at that, all things considered. If the universe is 'rich in life', most of it is probably micro-organisms that…

Agreed. It’s a minuscule probability per planet multiplied by a vast number of planets and it’s hard to say which factor carries greater weight. The fact that we haven’t detected any signals from space also sets a limit on the likelihood/duration of intelligent life in our area of the universe.

Re: Milky Way, 12 years, 1250 hours of exposures and 125 x 22 degrees of sky

#122

Post by medstrom »

quesera wrote: post #85
phaedrus wrote: post #60

Earlier quoted context omitted.

Something about that Orion photo in particular makes it seem beyond belief that there is not other life around other stars in the galaxy.

For me, it was this image and story that removed any shred of doubt: https://en.wikipedia.org/wiki/Hubble_Deep_Field The tiny speck of dust that is our whole world is less than a grain of sand on the beaches of the universe. We are not alone. Which doesn't mean that we would want to meet any of our neighbors!

Frankly, since we only have ourselves to sample, we have no idea how large the survivorship bias is. It doesn't matter if there's googol of galaxies or just one galaxy, we have zero direct information on how easily life arises. Putting it another way, observing a googol of galaxies ought to pretty much not at all increase our confidence that other life exists, like how observing a 200% increase in a speed doesn't tell you anything when you don't know what the absolute speed was to start with.

Re: Milky Way, 12 years, 1250 hours of exposures and 125 x 22 degrees of sky

#123

Post by piva00 »

quesera wrote: post #82
wahern wrote: post #74

Earlier quoted context omitted.

Even w/ a clear desert sky hundreds of miles from the nearest city (e.g. middle of Nevada), the sky looks nothing like these pictures. Astrophotography uses exposure times many multiples--and usually several orders of magnitude--longer than the human eye. Can you see the Milkyway? No, not really; not without prompting. If you have no idea what to look for, the disc is just a barely imperceptible, slight increase in o…

I agree with your larger premise, but: > Can you see the Milkyway? No, not really This is not my experience. I have seen the Milky Way very clearly from a few locations in the US. None are particularly remote -- all are just a few hours drive from the large cities I've lived in. Winter months are clearer than summer.

Completely agree, I've seen the Milky Way just by traveling to a city called Eskilstuna, some 200km away from Stockholm, in the middle of the forest and away from settlements you could see the Milky Way much brighter than just a faint streak of light.

Re: Milky Way, 12 years, 1250 hours of exposures and 125 x 22 degrees of sky

#124

Post by jonplackett »

ninkendo wrote: post #112
jonplackett wrote: post #101

Earlier quoted context omitted.

Even with extended life span ain't nobody ever going to another galaxy. Even if we could travel at the speed of light, it would take 2.5 million years just to get to the nearest galaxy.

If we could travel appreciably close to the speed of light, the journey could be close to instantaneous for the traveler. (Depending obviously on how close to light speed we’re talking about.) Time dilation is a nice property.

It might make more sense to take off in your near-light-speed ship, do a few laps of the galaxy, then return home for a thousand-years-in-the-future ship upgrade, then head on to another galaxy.

Re: Milky Way, 12 years, 1250 hours of exposures and 125 x 22 degrees of sky

#125

Post by jonplackett »

Calamity wrote: post #116
ninkendo wrote: post #112

Earlier quoted context omitted.

If we could travel appreciably close to the speed of light, the journey could be close to instantaneous for the traveler. (Depending obviously on how close to light speed we’re talking about.) Time dilation is a nice property.

Indeed - something often misunderstood as always recorded from the perspective of a third party observer. Quick follow up question. If you did depart and travelled at near-ligth speed to another galaxy, arrived there in a few seconds and then looked back at the earth - would it appear as only a few seconds have passed for the earthlings back home as well? By the same token, if you are actively watching another galaxy…

I think the downside is that for earth, time is passing by at 'normal' speed. So as soon as you get up to speed you're leaving behind, possibly the entire human race.

Weird to think that too if aliens show up. Their entire civilisation is probably already gone (unless it's VERY stable over hundreds of thousands of years).

Re: Milky Way, 12 years, 1250 hours of exposures and 125 x 22 degrees of sky

#126

Post by jonplackett »

kvetching wrote: post #106
jonplackett wrote: post #101

Earlier quoted context omitted.

Even with extended life span ain't nobody ever going to another galaxy. Even if we could travel at the speed of light, it would take 2.5 million years just to get to the nearest galaxy.

There has to be a hack.

Wormholes, maybe?

Re: Milky Way, 12 years, 1250 hours of exposures and 125 x 22 degrees of sky

#127

Post by jonplackett »

groby_b wrote: post #108
jonplackett wrote: post #86

Holy crap the universe is massive. It occurred to me the other day that there's barely any science fiction that even occurs outside our own galaxy (Star Wars being the exception that proves the rule). And if it does it's usually something from Andromeda right 'next door'. Even Star Trek only leaves the galaxy maybe one time, and that requires the help of Q.

Wait, what? In what universe is there "barely any science fiction" outside our galaxy? Lensman. The entire Revelation Space series. Beyond the Aquila Rift. Player of Games. Algebraist. Sirens of Titan. Perry Rhodan. And that's off the top of my head. There's quite a bit of SF (both good and trash, and I think the above list has both :) happening outside our galaxy.

Thanks I'll check these out!

I guess I was thinking more about ones that have intergalactic travel. Do any of these actually have travel between galaxies or are they just set in an alt galaxy? Sorry, I din't really explain that thinking very clearly.

Re: Milky Way, 12 years, 1250 hours of exposures and 125 x 22 degrees of sky

#128

Post by TrispusAttucks »

medstrom wrote: post #122
quesera wrote: post #85

Earlier quoted context omitted.

For me, it was this image and story that removed any shred of doubt: https://en.wikipedia.org/wiki/Hubble_Deep_Field The tiny speck of dust that is our whole world is less than a grain of sand on the beaches of the universe. We are not alone. Which doesn't mean that we would want to meet any of our neighbors!

Frankly, since we only have ourselves to sample, we have no idea how large the survivorship bias is. It doesn't matter if there's googol of galaxies or just one galaxy, we have zero direct information on how easily life arises. Putting it another way, observing a googol of galaxies ought to pretty much not at all increase our confidence that other life exists, like how observing a 200% increase in a speed doesn't tel…

You're right in regards to sample size.

However, one thing this argument often ignores is that the Earth is 4.5 billion years old. Life is 3.5 billion years old. The Earth was hot molten rock up until about 20 million years before life began.

So we went from Zero to Life in 20 million.

Once created it was so successful that it took over nearly every part of the Earth in a multitude of evolving forms.

It seems improbable life makes it's appearance so improbably early on Earth that perhaps the only explanation is that life isn't so improbable after all. Perhaps it's even highly likely give the physics of the universe.

Re: Milky Way, 12 years, 1250 hours of exposures and 125 x 22 degrees of sky

#129

Post by AnIdiotOnTheNet »

groby_b wrote: post #104
AnIdiotOnTheNet wrote: post #48

Earlier quoted context omitted.

Depends on what you mean by "civilized", but I take your point. I do wonder, however, if there isn't a correlation between the increase of light pollution and the trend away from reverence for gods. In other words, does the ability to see the grandeur of the heavens on a daily basis influence us to believe in greater beings?

Why is a belief in "greater beings" good or helpful?

I made no value judgement in my post.

Re: Milky Way, 12 years, 1250 hours of exposures and 125 x 22 degrees of sky

#130

Post by quesera »

medstrom wrote: post #122
quesera wrote: post #85

Earlier quoted context omitted.

For me, it was this image and story that removed any shred of doubt: https://en.wikipedia.org/wiki/Hubble_Deep_Field The tiny speck of dust that is our whole world is less than a grain of sand on the beaches of the universe. We are not alone. Which doesn't mean that we would want to meet any of our neighbors!

Frankly, since we only have ourselves to sample, we have no idea how large the survivorship bias is. It doesn't matter if there's googol of galaxies or just one galaxy, we have zero direct information on how easily life arises. Putting it another way, observing a googol of galaxies ought to pretty much not at all increase our confidence that other life exists, like how observing a 200% increase in a speed doesn't tel…

This is true, but I don't find it persuasive.

We know that simple chemistry plus lots of energy can create more complicated chemistry. We have evidence that some protein molecules can be self-replicating under the right conditions.

Given billions of parallel experiments over billions of years, I think it is vanishingly unlikely that exactly one has progressed to the point we would recognize as self-organizing.

But that's faith, not proof. I'll defend it as the most reasonable and non-exceptional version of the story, but I won't claim it as absolute truth.

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