A long way from home
September 18, 2012 6:48 AM   Subscribe

Regarding the first linked photo: what would that look like with a longer exposure time? Are there any photos out there that show the stars "behind" Earth?
posted by curious nu at 6:52 AM on September 18, 2012

Boy, it's weird to think that the two Voyager spacecraft could end up being the last human artifacts in existence.
posted by Malor at 6:59 AM on September 18, 2012 [17 favorites]

Is this the image that Carl Sagan convinced NASA to take? To turn around one of the spacecraft and take an evocative picture of Earth?
posted by three blind mice at 7:08 AM on September 18, 2012

I think the Sagan one was the "pale blue dot" picture, from way further out.
posted by Cironian at 7:09 AM on September 18, 2012

Is this the image that Carl Sagan convinced NASA to take? To turn around one of the spacecraft and take an evocative picture of Earth?

The one Sagan advocated for NASA to take was from the edge of the solar system and shows the Earth as a nearly-indistinguishable dot.
posted by aught at 7:14 AM on September 18, 2012 [1 favorite]

I'm just sad I won't be alive to witness its return to destroy the earth before departing for another dimension in a flash of cheesy 70s special effects.
posted by The 10th Regiment of Foot at 7:20 AM on September 18, 2012 [1 favorite]

...with data taking 16 hours and 38 minutes to reach Earth.

Think about that. After all this time, it's only 16 light-hours away.

I'm just sad I won't be alive to witness its return to destroy the earth before departing for another dimension in a flash of cheesy 70s special effects.

Silly! That was Voyager 6, not Voyager 1. ;-)
posted by aught at 7:27 AM on September 18, 2012

What will signal to the scientists that Voyager 1 has finally reached true "interstellar space"?
posted by Egg Shen at 7:30 AM on September 18, 2012

what would that look like with a longer exposure time? Are there any photos out there that show the stars "behind" Earth?

The Earth is fantastically bright. A longer exposure would simply result in the Earth overpowering the shot even more.
posted by Thorzdad at 7:33 AM on September 18, 2012 [1 favorite]

The same shot, 13 years later.

[With the requisite narration from Carl Sagan that is pretty much the best speech ever.]
posted by schmod at 7:33 AM on September 18, 2012 [3 favorites]

It still astounds me that we're able to take pictures from outer space.
posted by xingcat at 7:38 AM on September 18, 2012 [8 favorites]

The Earth is a sunlit object. Expose accordingly.
posted by Egg Shen at 7:43 AM on September 18, 2012

What will signal to the scientists that Voyager 1 has finally reached true "interstellar space"?

The speed and direction of the solar wind particles, mainly, as well as the strength and direction of the Sun's magnetic field and intensity of cosmic rays.
posted by aught at 7:47 AM on September 18, 2012 [1 favorite]

The speed and direction of the solar wind particles, mainly, as well as the strength and direction of the Sun's magnetic field and intensity of cosmic rays.

I've assumed that, by definition, "interstellar space" would require there to be no such wind or field.

Wrong?
posted by Egg Shen at 7:53 AM on September 18, 2012

That's so awesome. Pictures like that make me simultaneously proud and humbled.

Come so far, so far to go.
posted by Mooski at 7:54 AM on September 18, 2012 [3 favorites]

Outer space is so fucking cool.
posted by JohnnyGunn at 7:56 AM on September 18, 2012 [4 favorites]

Thinking about the scale of the cosmos--that something moving at forty thousand miles per hour will take eight times longer than all of recorded human history to even approach what will then be the closest star to our Pale Blue Dot--is beyond mind-boggling. It's a lung-busting gravity bong rip that leads the mind to awe and dread and everything between and beyond.

It's liberating to think of how much else there is in the universe, and at the same time frustrating to know that we, and our ancestors for who-knows-how-many generations, will never explore it in person, never touch the surface of an extrasolar planet, never be warmed by another star. The Voyagers are on the most fabulous vacation imaginable and sending us "Wish You Were Here" postcards from places we'll never visit.
posted by uncleozzy at 7:58 AM on September 18, 2012 [6 favorites]

After all this time, it's only 16 light-hours away.

In fairness, light can circle the Earth 7 times in a second. So 16 light-hours is pretty fucking epic on a terrestrial scale.

It's just that, as noted above, terrestrial scale is so pissant in cosmic terms.
posted by Egg Shen at 8:01 AM on September 18, 2012

Using currently known methods (even if experimental), could current technology theoretically make a vehicle fast enough to catch up to Voyager? And if not now, approximately how far away in the future would it be possible (using a reasonably conservative rate of technological advancement)?

Of course, you could make a device that goes a little faster and eventually catch up, but I'm talking about something that could catch up to it in, say, less than half the time Voyager took to get to the position where the two vehicles would meet.
posted by chambers at 8:02 AM on September 18, 2012

Imagine if we keep sending vehicles over time, centuries even, that keep meeting up with Voyager, and add onto the craft, making it a larger, faster, and more robust vehicle as decades and centuries pass. It would be a weird layer cake containing technological strata from different eras.

I kinda think Sagan would dig that.
posted by chambers at 8:07 AM on September 18, 2012

Using currently known methods (even if experimental), could current technology theoretically make a vehicle fast enough to catch up to Voyager?

Perhaps an ion drive, as used on the Dawn or Deep Space probes?
posted by Brandon Blatcher at 8:09 AM on September 18, 2012

The Earth is a sunlit object. Expose accordingly.

The Earth is a sunlit object with a rather high albedo -- about .3. The moon is a sunlit object with a lower albedo, .13, but it has a strong directional component. The moon doesn't reflect light equally in all directions, which is why a full moon is brighter, because the effective albedo is higher when the light is reflecting nearly 90° back, and would be a further 30% brighter if it reflected exactly backwards. We don't see that, because we call such times "a full lunar eclipse."

That's why the moon appears substantially dimmer in this pic -- and why it was substantially brightened in post-process to make it show up clearly in the photo. Otherwise, it would either be invisible or a barely visible smudge.

Never mind the chances of seeing a star. The apparent magnitude of the quarter moon is about -10, the Earth, full, from the moon is magnitude -17.7, so the quarter earth would be about -15. That means the moon is about 100 times dimmer than the Earth. Stars? The brightest one is Sirius at -1.6, which means that it's some 2300x dimmer than the moon, here, and about 230,000x dimmer than the Earth.

So, no stars. And a shot that was exposed for the stars would be nothing but a solid feild of white from the Earth's glow.
posted by eriko at 8:13 AM on September 18, 2012 [7 favorites]

eriko: Would it be possible to do what they've done with the solar observing satellites lately? A giant 'block' in front of where the Earth would be, to allow imaging around?

IF the world ever decided to send a satellite like Voyager out again, I mean.
posted by DigDoug at 8:17 AM on September 18, 2012

Voyager's twitter feed is pretty good stuff, though right now it's full of anniversary-related messages. Most of the time it's "I am so-many million miles from earth, so many hours of light time" and the status of various commands that have been sent.
posted by jquinby at 8:22 AM on September 18, 2012

Using currently known methods (even if experimental), could current technology theoretically make a vehicle fast enough to catch up to Voyager? And if not now, approximately how far away in the future would it be possible (using a reasonably conservative rate of technological advancement)?

Voyager except for the initial launch and the times it slingshots around planets, Voyager is just coasting through space. If you had any sort of spaceship that could accelerate continuously (an Orion dropping atom bombs behind it, a light sail pushed by a big laser beam or riding the solar wind, or even a chemical rocket that using fuel lifted to orbit in a space elevator or gathered from someplace like an asteroid where it wouldn't need to use all the fuel to lift it's own weight out of the gravity field), you could catch up to Voyager pretty quickly, depending on how much acceleration you had.

If you could accelerate constantly at 1/100 of Earth's gravity, Jupiter is 58 days away. At .1g, Jupiter is 18 days away. At .1g, Saturn is 26 days away. Much more if you want to stop when you get there.

If you accelerate at A gravities to midpoint, then turnover and then decelerate at A gravities to your destination, elapsed time is approximately 4 SQRT (D/A) days, with D in astronomical units.
posted by straight at 8:25 AM on September 18, 2012 [1 favorite]

It looks like the current max speed of ion drives is around 200,000 mph - voyager is going about 57,600mph, so it may be possible to catch up to it with current tech. Although to actually slow down and physically link up to it and not just whiz by is an entirely different matter.
posted by chambers at 8:26 AM on September 18, 2012

I've assumed that, by definition, "interstellar space" would require there to be no such wind or field.

At the risk of paraphrasing the linked article, the working theories generally predict Voyager will move through a zone of solar wind turbulence to a kind of boundary where the solar wind is deflected and moving at a right angle to the direction of the sun, then will pass beyond that to encounter a weaker but more complex interstellar medium of solar-wind-like plasma emitted by nearby stars and more distant supernovae. How closely the evidence will support these ideas of course still remains to be seen.

Using currently known methods (even if experimental), could current technology theoretically make a vehicle fast enough to catch up to Voyager?

Most of the variations among speeds of outer solar system probes result from differences in the trajectory when the probe is sling-shotted around Jupiter or one of the other big planets, rather than some kind of active engine propelling them, but I imagine there are more aggressive angles we could use to achieve higher velocities. I think New Horizons will reach Pluto in 9 years as opposed to the 12 or 13 years it took the Voyagers to get to the orbit of Pluto, so just looking at that, clearly a new probe could eventually catch up to earlier distant ones.
posted by aught at 8:28 AM on September 18, 2012 [1 favorite]

The Voyagers and Pioneers will soon have company as New Horizons aims for a Pluto flypast in 2016.

And, sadly, that's it for the outer planets. After Cassini's demise in 2017 there's one final mission - Juno - which is on its way to Jupiter for a couple of years orbiting in 2016-7. Then... nothing. There's talk of landing on Europa or Titan, but it takes a long time to get from talk to launch.

The Voyagers themselves will finish their missions around 2021, with New Horizons expected to last until it reaches 50 AU in around 2026.
posted by Devonian at 8:35 AM on September 18, 2012 [1 favorite]

Boy, it's weird to think that the two Voyager spacecraft could end up being the last human artifacts in existence.

You might be right, but I hope you're wrong.

More optimistically, I can imagine some future scenario in which they're given a type of "UN world heritage" status that would seek to protect them (from interference from other spacecraft) on their current trajectories to honor the legacy of the human race's early spacefaring days.
posted by BobbyVan at 8:43 AM on September 18, 2012 [3 favorites]

There's talk of landing on Europa or Titan

I'd love to see that happen in my lifetime.
posted by Mister_A at 8:45 AM on September 18, 2012

And, sadly, that's it for the outer planets.

It is sad. The Uranus and Neptune systems certainly each merit at least a serious Galileo/Cassini-style orbiter mission to fully explore these complex systems of moons and rings. There have been proposals, but as Devonian says, it takes a long time to get from proposal to funding to development to launch, and the 1-2 punch of the increasing emphasis on manned missions and economic crises in the U.S. and Europe make me doubt anything will happen on this front in the next decade at least.
posted by aught at 8:48 AM on September 18, 2012

And it looks to me that we're going to degenerate into "Moties", squabbling over the home rock without even getting to populate the asteroids and other real estate in the system before we flicker out. Because the cash and resources needed to get OUT of here while we still have them, would be more useful spent on buying another yacht, placing another political pawn, some more conquests of resource bearing areas... And if people left the gravity well, how would the current powers that be maintain control anyhow?

The pictures just hurt to look at after 30 years of effectively turning our backs on manned exploration or even sending humans beyond low orbit. They're not kidding when they say the big regrets are the things you didn't do, not the ones you did. Goes for cultures as well as individuals.
posted by bert2368 at 8:59 AM on September 18, 2012 [7 favorites]

I'd love to see that happen in my lifetime.

ATTEMPT NO LANDING THERE

couldn't resist; sorry
posted by jquinby at 9:05 AM on September 18, 2012 [5 favorites]

Next stop? The red dwarf star Gliese 445 in the constellation of Camelopardalis in the year 40,272 AD.

I hope it doesn't find Necrons, Tyranids or Chaos demons there.
posted by Gelatin at 9:19 AM on September 18, 2012

Another problem is that we're running out of plutonium-238, which is the only suitable power source for deep space missions and hasn't been made for decades (it's a byproduct of nuclear missile warhead manufacturing). There's enough for one more mission (sorry, Space.com link) but that's it. Juno is solar-powered, which is quite some feat out at Jupiter, but if we're going to land on a moon or two that won't cut it.

We could make more, but that's expensive and politically messy. We used to buy some from Russia, but it's not in the market now.
posted by Devonian at 9:24 AM on September 18, 2012 [1 favorite]

Goes for cultures as well as individuals.

On the other hand, culturally, it's still very very early years. Humans may well crash and rebuild a dozen times before we get it right. (Not much consolation to those of us with scant decades ahead of us.)

Happily, if it does it includes a handy map designed to lead any such critters back to us. ;-)
posted by aught at 9:51 AM on September 18, 2012

The one Sagan advocated for NASA to take was from the edge of the solar system and shows the Earth as a nearly-indistinguishable dot.

Wow, I had never seen this shot or heard of it before. I was not prepared for how it made me feel: a little lost and very lonely but somehow deeply hopeful. Not sure what that means.
posted by lakersfan1222 at 10:51 AM on September 18, 2012

it's weird to think that the two Voyager spacecraft could end up being the last human artifacts in existence.

The garbage we left on the Moon will be there for another 5 billion years until the Sun enters its red giant phase.

But yeah, those gold records will probably make it to the heat death of the universe.
posted by Egg Shen at 11:19 AM on September 18, 2012

Nice photo: my new wallpaper.

Werner told me I could go to the moon. He was there, on black and white TV. Walt promised, smiling through his broomy mustache, mickey waving and jumping up and down. Tomorrowland. He showed me the drawings. I believed them.

Bah!
posted by mule98J at 11:47 AM on September 18, 2012 [1 favorite]

The garbage we left on the Moon will be there for another 5 billion years until the Sun enters its red giant phase.

Or until it's disrupted by a near-enough meteor strike. I wonder what the probability of that over the next 5 billion years is?
posted by ROU_Xenophobe at 11:52 AM on September 18, 2012

It looks like the current max speed of ion drives is around 200,000 mph - voyager is going about 57,600mph, so it may be possible to catch up to it with current tech.

To reach out and flip the record? That tone arm's been skipping a long while now.
posted by Durn Bronzefist at 11:54 AM on September 18, 2012 [1 favorite]

I just closed the thread about the polar ice melting and this is the next thread. It's ime for alcohol.
posted by ersatz at 2:00 PM on September 18, 2012

Well, ime for alcohol if you're not.

I can imagine some future scenario in which they're given a type of "UN world heritage" status that would seek to protect them (from interference from other spacecraft)

Good luck getting the Klingon Empire to honor that, though!

Anyway, on the overall exploration front, I'm optimistic that various technologies -- from propulsion to launch to computing to communications -- will create a kind of confluence or disruptive matriculation to the next level of exploration, in a lots-of-cheap-craft kind of way. It's hard to see these things in advance, but we've been coasting on incremental improvements for a while now. Besides, the US isn't the only nation interested in this sort of thing now, and the opportunity to collaborate might end up being the way we solve the funding aspect.

Meantime, we have this emphasis on possible human exploration of the Moon and Mars, which itself may provide a basis for less-expensive spinoffs from what will undoubtedly be a massive spending spree, in a why not? spirit.
posted by dhartung at 3:14 PM on September 18, 2012 [1 favorite]

We are trapped on an insignificant blue speck surrounded by nothing with only the barest sliver of time to contemplate it all.
posted by humanfont at 7:14 PM on September 18, 2012 [1 favorite]

Malor: "Boy, it's weird to think that the two Voyager spacecraft could end up being the last human artifacts in existence."

Don't forget good, old Pioneers 10 and 11. They have the bonus of having plaques that show, among other things, human naughty bits.
posted by InsertNiftyNameHere at 1:25 AM on September 19, 2012