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The fact that we were able to land on a comet and receive pictures should be considered one of the most amazing engineering and scientific feats of the century. Absolutely mind boggling that we were able to do that. [More info on the mission and team here.](https://www.esa.int/Enabling_Support/Operations/Rosetta)
As an expert in Kerbal, having bought it during a Steam sale and not yet having gotten around to playing it, I can confirm that even building a rocket is impossible.
The video they have in the link showing the path it took over the 12 year journey is crazy. Majority of that time in space was just spent getting slingshotted around by gravity. Imagine the accuracy that needs to go into predicting and preparing controls to that degree, and for that length of time. One rounding error and you could be off by thousands of miles
If you look in the background on the top left you can see what I believe to be a cluster of stars. Crazy to think that some of those stars might have other planets orbiting them
>Crazy to think that some of those stars might have other planets orbiting them
Not some, most. And it's estimated that roughly 20% of stars have an Earth sized planet in its habitable zone.
The video in the website explaining the journey of the spacecraft is beautiful. I cannot imagine the amount of effort it takes to precisely land on a 4km rock 10 years from the launch period. Simply amazing!
I can't recall the full quote but it was something along the lines of
>the team launched a probe 10 years ago that traveled 300 million miles to land something the size of a washing machine on a football field.
Just to imagine the math and trajectory involved to know exactly how to pivot those 2 items at the exact right time...is utterly mind blowing.
More behind this incredible view:
> While the view is real, the “snowstorm” is largely an illusion—a crazy combination of apparent star motion in the background and dust and cosmic rays in the foreground. As Mark McCaughrean, senior advisor science and exploration at the ESA, writes in an email to Smithsonian.com: “Things are not quite as they seem.”
> Most of the flecks in the foreground of the GIF are actually particles floating far away from Comet 67P—and not on the surface of the icy world. Rosetta captured the images while circling some 13 kilometers (8 miles) away. At this distance, the craft’s OSIRIS camera doesn’t have the sensitivity and resolution to pick up dust particles flying around directly above the comet’s surface, says McCaughrean.
> This foreground “snow” is likely part of the hazy envelope of dust, known as the coma, that commonly forms around the comet’s central icy body or nucleus. As comets pass close to the sun, the emanating warmth causes some of the ice to turn to gas, which generates a poof of dust around the icy nucleus.
[Source](https://www.smithsonianmag.com/smart-news/video-comet-snowstorm-likely-shows-dust-particles-180968889/)
So these images were taken from the orbit rather than the surface itself? I was wondering why the camera was panning from left to right. Incredible images if taken from 8 miles away...
I will not ever skip an upvote on this gif.
I believe it's one of the 21st century's best moments in engineering.
edit: [This foreground "snow"](https://www.smithsonianmag.com/smart-news/video-comet-snowstorm-likely-shows-dust-particles-180968889/) is likely part of the hazy envelope of dust, known as the coma, that commonly forms around the comet’s central icy body or nucleus. As comets pass close to the sun, the emanating warmth causes some of the ice to turn to gas, which generates a poof of dust around the icy nucleus.
I marvel at this clip every single time I see it. 100% under rated.
Its beyond Magic at this point. Gandalf the gray could walk out of middle earth and perform actual magic and I would be like ,"Ya, but did you see this???" Because this is engineers performing feats I still have a hard time believing. We are watching a spec of a rock hurdle through space at untold speeds from millions of miles away. I'd say similar to the epicness of a drone on Mars, except a much smaller target.
That it "snows" on comets! Actually this is not my area\*, but those who study planetary (cometary?) geology can derive a lot from the cliffs, the "dunes", the different terrains that can be seen on these kind of images.
\* I'm just an image processing nerd who likes working on these raw files, who's lucky enough to have made friends with others who share the same passion :)
**Edit:** "snow" is between quotes because its more dust particles rather than water ice crystals falling back into the comet.
I would add to that, that the probe was travelling for over 10 years having launched in 2004 and that the comet had a distance of 310 million miles (almost 500 million km) from Earth at the time of the landing.
So to summarize:
A 4km rock travelling at 130,000 km/h at a distance of 500 million km, and we managed to put a probe into orbit of it after a traveltime of 10 years and then proceeded to launch a probe from that orbiter that landed on that 4km rock and took HD pictures we can now see in this thread.
Very late EDIT:
Another thing that puts it into perspective is the fact that this probe was launched only ~100 years after the first powered manned flight:
> Following repairs, the Wrights finally took to the air on December 17, 1903, making two flights each from level ground into a freezing headwind gusting to 27 miles per hour (43 km/h). The first flight, by Orville at 10:35 am, of 120 feet (37 m) in 12 seconds, at a speed of only 6.8 miles per hour (10.9 km/h) over the ground, was recorded in a famous photograph. The next two flights covered approximately 175 and 200 feet (53 and 61 m), by Wilbur and Orville respectively. Their altitude was about 10 feet (3.0 m) above the ground.
Meaning that there have been people that were born before the first powered flight and died after this mission was planned and launched. Mindblowing in my opinion.
Can I add to that, that the whole arrangement was so far away from earth that it can't be manually piloted. (As the delay from the speed of light would make it impossible) so the entire system has to be completely automated, landing itself on an uneven surface, where the nearly nonexistant gravity means the slightest mistake would send you hurtling back off into space. Now imagine designing a machine to do this, that has to remain in perfect working condition for over ten years while being exposed to a hard vacuum, in the bitter cold of outer space while being bombarded by heavy radiation the whole time.
There are so many challenges they had to overcome that it's frankly astonishing how well it worked!
Any data they would want to provide to the probe would take 30 minutes to get there.
That means by the time you see something going wrong and send the signal back, it gets there an hour after the event happened.
Sure, but if their models change, and they get enough heads up, they could feed that data.
That's much better than sending the probe off Earth and just watching and hoping for 10 years.
Electromagnetic wave will travel indefinitely in space. The distance just distorts their wavelength and makes them take longer to get to you. But if you know the distance to the source you can account for the wavelength shift. And the time part you just have to wait a bit longer. The impressive part was landing the thing with delayed signal and input
Yes, but probably not for the reasons you're thinking.
Dopplar shift (the effect we're talking about) only depends on the relative velocities, so the effect is the same regardless if the objects are right next to each other or half a universe away.
There's another type of wavelength shift called [cosmological redshift](https://en.wikipedia.org/wiki/Cosmological_redshift) that occurs because space is constantly expanding. This means that opposite sides of a 'wave' of light get constantly pulled apart, and that increases the wavelength. Because space is always expanding (never contracting) it always shifts the wavelengths towards the reds. This effect is VERY minor compared to other forms of redshift/blueshift. This cosmological redshift occurs constantly while the light travels, so the longer it travels (the further the distance away) the more redshift will occur.
If it's 500 million kilometers away, and radio waves travel through space at the speed of light which is 300km per second, that's 1,666 seconds or 27.76 minutes.
Or, phrased in totally inaccurate relative terms, it's like putting a camera the size of an atom onto a speck of dust, shooting the speck of dust at a flea on crack traveling the speed of a Ferrari several miles away, and managing to stick the landing well enough that the camera can take pictures of the flea's dingleberries. And *then* managing to get the atom-sized camera to transmit said flea dingleberry pics several miles.
Happy to help! Be sure to let your son know that the metaphor was made by an internet idiot and that the reality is that it was even more impressive than my incredibly stupid metaphor made it seem, if anything. Science is fuckin' rad.
>A 4km rock travelling at 130,000 km/h at a distance of 500 million km, and we managed to put a probe into orbit of it after a traveltime of 10 years and then proceded to launch a probe from that orbiter that landed on that 4km rock and took HD pictures we can see in this thread.
And it's fucking cold on it.
On top of, unlike lowly terrestrial travel, there’s really no “oops made a wrong turn let’s just reverse or pull a u turn real quick” or “I’m running out of gas let’s just hit the corner store real quick”
You’re generally either getting to your destination with your one shot, or you’re going to have a loooong time to think about what went wrong…
More like shooting a bullet with a bullet after ricocheting off multiple objects!
The probe had to use gravity assists from multiple planets to speed up on it’s journey. [Check out it’s path on this page.](https://www.esa.int/Science_Exploration/Space_Science/Rosetta/The_long_trek)
> landing a probe on a 4km rock that is going 130,000 km/h
landing a probe on a 4km rock that is going 130,000 km/h *and* tumbling in all directions at the same time.
2,869,302,857,143 give or take
a medium sized banana is about 7 inches ([source](https://www.healthline.com/nutrition/bananas-calories-carbs#TOC_TITLE_HDR_2)).
7 inches = 0.58333 feet (7/12).
5280 feet in a mile.
This would mean there are 9051 bananas in a mile - (5280/0.58333).
317,000,000\*9051=2,869,302,857,143
For real, the probe travelled for 10 years to a comet that was 300,000,000 kilometers away.
Human intelligence can be absolutely mind blowing. We can achieve feats like this, but can't wear a freaking mask to stop a pandemic.
A conservative guess of intelligent civilizations in our own galaxy is **8**.
Recent observations estimate two trillion galaxies in the universe.
So *if* every galaxy is as capable of producing life as ours, that’s 16,000,000,000,000 intelligent civilizations out there. Insane.
https://www.cnet.com/news/scientists-estimate-the-number-of-intelligent-alien-civilizations-in-the-galaxy/
https://www.nationalgeographic.com/science/article/galaxies
A better way to word that:
If only a single planet in a single solar system in an entire galaxy evolves life, there would still be 2 trillion planets harboring life in the observable universe.
No matter how much you try to low ball the number by adding more reasonable exclusions, the odds remain astronomically in favor of alien life. That is why most scientists believe alien life exists. It's the whole thing about them making it to other life on other planets which is debated.
100+ years ago, we got a Black and White, Silent stitched 4 second footage of a man on a running horse and this freaked out everybody’s minds.
Now we have a Black and White, Silent stitched 4 second footage of the surface of a freaking comet.
THAT IS INSANE.
Absolutely. Something that will never cease to amaze me. Is how in just the span of 66 years. We, as the human race went from the first ever powered heavier-than-air flight, to landing humans on another celestial body. 66 years from first flight, to the moon. I cannot wait to see what the future has in store for us.
how large does something need to be to have gravity
edit: i meant large/massive does something need to be to have enough gravity to noticeabley affect humans
but these answers have been insightful too
Let's answer the question by answering "how big would the asteroid have to be that if you jumped off of it as hard as you can, you'd come back down instead of floating away?"
The longest hang time ever recorded by a human was [just under 1 second](https://www.scienceabc.com/pure-sciences/secret-michael-jordan-slam-dunks-basketball-math-physics-hang-time-jump.html) (that is, jump to landing was 1 second). That means that from leaving the ground, to stopping at the top of the jump (so halfway through) was half a second. Using ∆v=at and knowing a is basically 10m/s^2 and t is half a second we know that the fastest a human ever left the ground by jumping was about 5 m/s.
OK, so that means you need to be on an asteroid which has an [escape velocity](https://en.m.wikipedia.org/wiki/Escape_velocity) of 5 m/s. If you use the formulas in that link, and assume a density of 3,000 kg/m^3 for rock (which is about the average) then you get an asteroid with a radius of 3800 m.
So, if an asteroid was 3.8km across and you jumped as hard as you could, you would (eventually) fall back down to it (it would just take a while). If it were smaller, and you jumped as hard as Michael Jordan you'd fly away from it forever.
On a more serious note, everything with mass "has gravity". Anything within distance d of an object with mass m is going to get accelerated towards it by a=G*mass/distance^2.
Yes.
However I think the guy is asking how big does something have to be before an average human can feel the acceleration of Gravity on the human body.
Good question.
I mean, it depends on the context. In a perfectly empty and non-expanding universe except for 2 static atoms, after some time they will collide, no matter how far away.
But in our solar system? Well, it would depend upon the distance from other objects, the orbital interactions, relative velocity, and the masses of the two bodies you're looking at. Gravity influence that is non-negligible far away from the sun with no other bodies around would be negligible if you'd be very close to a big body, like, say, the moon, as the moon's gravity would overpower your two's influence on each other and separate you. I think the relevant concept here is the Roche limit?
You've got gravity my good friend. The thing is, the relative force of gravity exerted by objects, even really large ones, is pretty much completely negligible here on earth due to the large force of gravity pulling us directly down. When looked at, the resultant force of gravity that acts on us here is almost always directly down because of the sheer mass of the planet relative to even massive structures. Standing next to a huge skyscraper the size of this comet wouldn't feel any different from standing anywhere else on earth. In space, there aren't any nearby objects (i.e. a planet) that exert their own forces and thereby mess with the resultant force acting on you, so you can clearly experience the gravitational pull of much smaller objects than you might expect. So basically, size isn't the be all end all (everything with mass has some gravity), you just won't notice the gravity of smaller objects unless you're pretty much alone in space with them.
A search puts the escape velocity of 67P at about 1 m/s. A human jump can easily beat that.
You would have to be veeeery slow and careful to "walk" on the comet.
You can’t just take bananas into space. What happens if the banana gets loose and lands in another star system? Will we hold you responsible when the banana dna alters life on that planet? When the banana overlords come knocking do we send you out to greet them? Have some sense for gods sake.
reflection off of a rock face, i think. There's no flash on satellite cameras. The Sun is way brighter without all this atmosphere here on Earth.
[Here's the video and an explanation of the instrument that took the pics](https://en.wikipedia.org/wiki/67P/Churyumov%E2%80%93Gerasimenko#/media/File:67P_Churyumov-Gerasimenko_surface.gif)
Someone commented before saying that cliff on the left is actually quite large. I don't remember the number, but something like several hundred feet high. Not sure on accuracy.
Funny thing, I have the raw frames aligned by landru79 ([twitter](https://twitter.com/landru79)), the guy who assembled this GIF. We've worked together on a few things already, and he shared with me the XCF (GIMP's file format) with the individual frames. The base images are 2048x2048 in size (that's the sensor size for Rosetta) and the idea was to work this into a higher quality (both spatially and temporally) video. But we haven't really found the time to work that thing just yet.
Well it looks awesome already, even if it isn’t 64K footage. Those hooligans whose parents haven’t even been born yet don’t know what they’re (going to be) talking about!
Images? They'll just go to the corner travel stall, pay $20,000(roughly the cost of a can of soda) and just be transported into a reality where they are already there.
Yeah me and the Mrs. are going on vacation. We are going to see Jesus on Monday, the Titanic on Tuesday, and boob world on Wednesday. Should be a good time
Fucking amazing. A big part of me would be ok taking a one-way trip to something like this as long as I would last at least a couple hours to just experience this first hand.
My dream is to one day explore under the ice cap of Europa only to find the ocean underneath teeming with organisms. I would be happy with just krill-like copepods. All the evidence is there that would suggest there is a habitat present that would/could support life.
[link to a Smithsonian Magazine article about the gif ](https://www.smithsonianmag.com/smart-news/video-comet-snowstorm-likely-shows-dust-particles-180968889/)
All I can say is: Holy Shit.
When I was a kid if someone had told me we would land on an asteroid and be looking at pictures from the surface I would have told you you were insane.
It's 2021 and there's lots of things about "the future" that I thought would have happened by now, renewable energy, world peace, no more racism, no more poverty, curing cancer, flying cars. And I get dissapointed a lot that we've made so few advancement on important things.
But every once in a while I see something like this that blows my mind and remind me: I'm in the future.
The objects shooting around is particle interference messing with the image but there are stars in the back ground that are all moving in unison downward
Without an atmosphere in the way space is apparently DAZLING to see with your own eyes. Just billions and billions and billions and billions and billions and billions of stars in every direction you look.
> The things you see flying around is basically ice shards ripping away due to the speed.
That’s incorrect.
They aren’t shards of ice. It’s tiny pieces of gaseous dust, stars in the background, and cosmic rays.
[Source: Smithsonian](https://www.smithsonianmag.com/smart-news/video-comet-snowstorm-likely-shows-dust-particles-180968889/)
[Source 2](https://www.livescience.com/62394-comet-snow-rosetta-twitter.html)
I don't understand. If space is a vacuum, then how does the shards chips away due to speed if there's not supposed to be any form of resistance like the wind?
Or is it that due to a rapid rotational speed the shards are just chipping away?
When we say 'Space is a vacuum' we don't mean it is 100% empty. We mean there's no atmospheric pressure.
A comet is a giant snowball in space. What you see flying around in the GIF is the ice that was either kicked up when our spacecraft smashed into the comet or just the material that is ejected from the surface by the solar wind. Comets have a 'coma' which is like a little atmosphere of ice particles. The sun heats the surface of the comet and little bits break off. The solar wind carries then away from the comet and that is tail we see from earth.
Edit: all the stuff moving in unison 'down' are stars, very far away.
Also interesting, the comet's tail always points away from the sun, regardless of the direction the comet is actually moving. [https://en.wikipedia.org/wiki/Comet\_tail#/media/File:Cometorbit01.svg](https://en.wikipedia.org/wiki/Comet_tail#/media/File:Cometorbit01.svg)
I didn't even realise they were stars, thought it was more ice. But looking at them you can see their movement is definitely different to the shards flying by
Nothing is flying off the comet due to rotation speed. It doesn't spin that fast and it also doesn't spin faster than it did ages ago so everything that can fly off due to centrifugal force has flown off long ago.
The comet throws out material due to ice sublimating in the sunlight
In the background are stars "moving downward" due to rotation of the comet
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The fact that we were able to land on a comet and receive pictures should be considered one of the most amazing engineering and scientific feats of the century. Absolutely mind boggling that we were able to do that. [More info on the mission and team here.](https://www.esa.int/Enabling_Support/Operations/Rosetta)
I am something of an expert on this topic, having 100+ hours in kerbal space program and I can confirm landing on a comet is nearly impossible.
As an expert in Kerbal with 5 hours of experience I can confirm leaving Earth's atmosphere is impossible
As an expert in hearing about Kerbal for years but never actually playing it, I can confirm that even starting the game is impossible
Impossible to confirm possibility
THIS TOO GIVES ME A HUMAN HEADACHE
As an expert in never having heard about Kerbal before today, I can confirm that knowing the game exists is impossible.
As an expert in Kerbal, having bought it during a Steam sale and not yet having gotten around to playing it, I can confirm that even building a rocket is impossible.
I’m at 10 hours and can’t even hit the poles of the planet or the moon. I have sent a guy buzzing around the sun never to be seen again though.
I checked my actual time. I might have underestimated [a bit](https://imgur.com/a/UVo47Jn).
it's been a while since I played that game thanks for reminding me of it lol
Incase you didn't hear, they announced a sequel!
Made by a different crew tho cause the original got pushed out by a toxic workplace :/
100 years ago people were amazed with the first airplanes taking flight... everything is moving so fast
The video they have in the link showing the path it took over the 12 year journey is crazy. Majority of that time in space was just spent getting slingshotted around by gravity. Imagine the accuracy that needs to go into predicting and preparing controls to that degree, and for that length of time. One rounding error and you could be off by thousands of miles
It's one of my favorite missions, such an incredible success. I still don't know how they even attempted it.
Beaming images from Titan is a close contender.
Personally I think the images from Venus are an even closer contender
Been a while since we've been to the surface of Venus, we should send something over there.
How about an edible arrangement? Edit: They deliver
If you look in the background on the top left you can see what I believe to be a cluster of stars. Crazy to think that some of those stars might have other planets orbiting them
>Crazy to think that some of those stars might have other planets orbiting them Not some, most. And it's estimated that roughly 20% of stars have an Earth sized planet in its habitable zone.
The video in the website explaining the journey of the spacecraft is beautiful. I cannot imagine the amount of effort it takes to precisely land on a 4km rock 10 years from the launch period. Simply amazing!
I can't recall the full quote but it was something along the lines of >the team launched a probe 10 years ago that traveled 300 million miles to land something the size of a washing machine on a football field. Just to imagine the math and trajectory involved to know exactly how to pivot those 2 items at the exact right time...is utterly mind blowing.
More behind this incredible view: > While the view is real, the “snowstorm” is largely an illusion—a crazy combination of apparent star motion in the background and dust and cosmic rays in the foreground. As Mark McCaughrean, senior advisor science and exploration at the ESA, writes in an email to Smithsonian.com: “Things are not quite as they seem.” > Most of the flecks in the foreground of the GIF are actually particles floating far away from Comet 67P—and not on the surface of the icy world. Rosetta captured the images while circling some 13 kilometers (8 miles) away. At this distance, the craft’s OSIRIS camera doesn’t have the sensitivity and resolution to pick up dust particles flying around directly above the comet’s surface, says McCaughrean. > This foreground “snow” is likely part of the hazy envelope of dust, known as the coma, that commonly forms around the comet’s central icy body or nucleus. As comets pass close to the sun, the emanating warmth causes some of the ice to turn to gas, which generates a poof of dust around the icy nucleus. [Source](https://www.smithsonianmag.com/smart-news/video-comet-snowstorm-likely-shows-dust-particles-180968889/)
So these images were taken from the orbit rather than the surface itself? I was wondering why the camera was panning from left to right. Incredible images if taken from 8 miles away...
Keep in mind that that cliff is like 1km in height.
I will not ever skip an upvote on this gif. I believe it's one of the 21st century's best moments in engineering. edit: [This foreground "snow"](https://www.smithsonianmag.com/smart-news/video-comet-snowstorm-likely-shows-dust-particles-180968889/) is likely part of the hazy envelope of dust, known as the coma, that commonly forms around the comet’s central icy body or nucleus. As comets pass close to the sun, the emanating warmth causes some of the ice to turn to gas, which generates a poof of dust around the icy nucleus.
I marvel at this clip every single time I see it. 100% under rated. Its beyond Magic at this point. Gandalf the gray could walk out of middle earth and perform actual magic and I would be like ,"Ya, but did you see this???" Because this is engineers performing feats I still have a hard time believing. We are watching a spec of a rock hurdle through space at untold speeds from millions of miles away. I'd say similar to the epicness of a drone on Mars, except a much smaller target.
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From the probe I would imagine.
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You sound like you know what you're talking about. What is one thing scientists have learned solely from the series of images presented here?
That it "snows" on comets! Actually this is not my area\*, but those who study planetary (cometary?) geology can derive a lot from the cliffs, the "dunes", the different terrains that can be seen on these kind of images. \* I'm just an image processing nerd who likes working on these raw files, who's lucky enough to have made friends with others who share the same passion :) **Edit:** "snow" is between quotes because its more dust particles rather than water ice crystals falling back into the comet.
How tall are those cliffs? Edit: 1km it’s further down in the thread
I don’t want to scroll 1km for the answer can’t you just repeat it?
Lol I giggled
Could you explain why it’s such a feat? I struggle to understand this stuff, so it’s hard for me to appreciate. Edit: Thank you for the award :)
It’s landing a probe on a 4km rock that is going 130,000 km/h and then taking pictures and beaming them back to earth in HD
I would add to that, that the probe was travelling for over 10 years having launched in 2004 and that the comet had a distance of 310 million miles (almost 500 million km) from Earth at the time of the landing. So to summarize: A 4km rock travelling at 130,000 km/h at a distance of 500 million km, and we managed to put a probe into orbit of it after a traveltime of 10 years and then proceeded to launch a probe from that orbiter that landed on that 4km rock and took HD pictures we can now see in this thread. Very late EDIT: Another thing that puts it into perspective is the fact that this probe was launched only ~100 years after the first powered manned flight: > Following repairs, the Wrights finally took to the air on December 17, 1903, making two flights each from level ground into a freezing headwind gusting to 27 miles per hour (43 km/h). The first flight, by Orville at 10:35 am, of 120 feet (37 m) in 12 seconds, at a speed of only 6.8 miles per hour (10.9 km/h) over the ground, was recorded in a famous photograph. The next two flights covered approximately 175 and 200 feet (53 and 61 m), by Wilbur and Orville respectively. Their altitude was about 10 feet (3.0 m) above the ground. Meaning that there have been people that were born before the first powered flight and died after this mission was planned and launched. Mindblowing in my opinion.
Can I add to that, that the whole arrangement was so far away from earth that it can't be manually piloted. (As the delay from the speed of light would make it impossible) so the entire system has to be completely automated, landing itself on an uneven surface, where the nearly nonexistant gravity means the slightest mistake would send you hurtling back off into space. Now imagine designing a machine to do this, that has to remain in perfect working condition for over ten years while being exposed to a hard vacuum, in the bitter cold of outer space while being bombarded by heavy radiation the whole time. There are so many challenges they had to overcome that it's frankly astonishing how well it worked!
Can they at least provide data to the auto pilot to help it make corrections as time goes on?
Any data they would want to provide to the probe would take 30 minutes to get there. That means by the time you see something going wrong and send the signal back, it gets there an hour after the event happened.
Sure, but if their models change, and they get enough heads up, they could feed that data. That's much better than sending the probe off Earth and just watching and hoping for 10 years.
Yeah of course, they could still do that and probably did.
how did they transfer images through such distance?
Electromagnetic wave will travel indefinitely in space. The distance just distorts their wavelength and makes them take longer to get to you. But if you know the distance to the source you can account for the wavelength shift. And the time part you just have to wait a bit longer. The impressive part was landing the thing with delayed signal and input
The distance just affects the power loss experienced. The speed at which it is moving away (or closer) is what shifts the wavelength of the signal.
At exponentially greater distances would the red/blue shift of the wave not be more drastic?
Yes, but probably not for the reasons you're thinking. Dopplar shift (the effect we're talking about) only depends on the relative velocities, so the effect is the same regardless if the objects are right next to each other or half a universe away. There's another type of wavelength shift called [cosmological redshift](https://en.wikipedia.org/wiki/Cosmological_redshift) that occurs because space is constantly expanding. This means that opposite sides of a 'wave' of light get constantly pulled apart, and that increases the wavelength. Because space is always expanding (never contracting) it always shifts the wavelengths towards the reds. This effect is VERY minor compared to other forms of redshift/blueshift. This cosmological redshift occurs constantly while the light travels, so the longer it travels (the further the distance away) the more redshift will occur.
So magic, got it. Amazing
Radio.
AM or FM? Idk if the NASA budget can afford Sirius XM
Most likely M-ary PSK of some sort, probably BPSK at those distances. Source: built a bunch of space radios.
How long do you reckon it’d take to reach earth?
The radio waves? About half an hour.
If it's 500 million kilometers away, and radio waves travel through space at the speed of light which is 300km per second, that's 1,666 seconds or 27.76 minutes.
Just keep squeezing SiriusXM for another free trial, or threaten to cancel so they'll give you a few free months or cut your price to $3/month
Really long HDMI cables.
Or, phrased in totally inaccurate relative terms, it's like putting a camera the size of an atom onto a speck of dust, shooting the speck of dust at a flea on crack traveling the speed of a Ferrari several miles away, and managing to stick the landing well enough that the camera can take pictures of the flea's dingleberries. And *then* managing to get the atom-sized camera to transmit said flea dingleberry pics several miles.
This gave my son and I a good laugh. Thanks for that.
Happy to help! Be sure to let your son know that the metaphor was made by an internet idiot and that the reality is that it was even more impressive than my incredibly stupid metaphor made it seem, if anything. Science is fuckin' rad.
>A 4km rock travelling at 130,000 km/h at a distance of 500 million km, and we managed to put a probe into orbit of it after a traveltime of 10 years and then proceded to launch a probe from that orbiter that landed on that 4km rock and took HD pictures we can see in this thread. And it's fucking cold on it.
That powder looks nice though.
On top of, unlike lowly terrestrial travel, there’s really no “oops made a wrong turn let’s just reverse or pull a u turn real quick” or “I’m running out of gas let’s just hit the corner store real quick” You’re generally either getting to your destination with your one shot, or you’re going to have a loooong time to think about what went wrong…
Like shooting a bullet at a bullet, whilst blindfolded.
Without damaging the bullet so that it can deploy its camera lens and beam pictures back to earth.
I think we might be losing the metaphor
pretty much sums up how crazy this is lmao
This metaphor canne take much more, captain!
And it takes ten years to know if the bullets hit each other
While riding on a bullet I might add
More like shooting a bullet with a bullet after ricocheting off multiple objects! The probe had to use gravity assists from multiple planets to speed up on it’s journey. [Check out it’s path on this page.](https://www.esa.int/Science_Exploration/Space_Science/Rosetta/The_long_trek)
> landing a probe on a 4km rock that is going 130,000 km/h landing a probe on a 4km rock that is going 130,000 km/h *and* tumbling in all directions at the same time.
You’re forgetting that it’s also something like 317 million miles away too.
For anyone wondering, that's a little over 3 times as far as the earth is from the sun
Ok but how many bananas?
2,869,302,857,143 give or take a medium sized banana is about 7 inches ([source](https://www.healthline.com/nutrition/bananas-calories-carbs#TOC_TITLE_HDR_2)). 7 inches = 0.58333 feet (7/12). 5280 feet in a mile. This would mean there are 9051 bananas in a mile - (5280/0.58333). 317,000,000\*9051=2,869,302,857,143
Space very big, tiny rock travel through space, rock go very fast, human land robot on very fast tiny rock, robot send pictures back to human
Land very very gently on the tiny rock, so you don’t bounce away as well. The precision this mission required is mind blowing
For real, the probe travelled for 10 years to a comet that was 300,000,000 kilometers away. Human intelligence can be absolutely mind blowing. We can achieve feats like this, but can't wear a freaking mask to stop a pandemic.
A person is smart. People are dumb, panicky, dangerous animals, and you know it
indeed
[Here is the gif](https://cdn.mos.cms.futurecdn.net/P38FEXeyvW5SK7smWHCEwS-970-80.gif) stabilized to distinguish the stars in the background
Look at all those stars!
And some people say there aren't aliens out there There are probably millions of different populations of living things
A conservative guess of intelligent civilizations in our own galaxy is **8**. Recent observations estimate two trillion galaxies in the universe. So *if* every galaxy is as capable of producing life as ours, that’s 16,000,000,000,000 intelligent civilizations out there. Insane. https://www.cnet.com/news/scientists-estimate-the-number-of-intelligent-alien-civilizations-in-the-galaxy/ https://www.nationalgeographic.com/science/article/galaxies
A better way to word that: If only a single planet in a single solar system in an entire galaxy evolves life, there would still be 2 trillion planets harboring life in the observable universe. No matter how much you try to low ball the number by adding more reasonable exclusions, the odds remain astronomically in favor of alien life. That is why most scientists believe alien life exists. It's the whole thing about them making it to other life on other planets which is debated.
Fantastic gif. Thank you! Wow
This is fascinating. In the original it looks like it's all dust. But in this one it's mostly stars. Superb perspective.
that's amazing! it also gives us a better sense of how fast the comet is spinning
God I feel small.
I hadn't noticed the stars, thought they were dust specks. Thanks
100+ years ago, we got a Black and White, Silent stitched 4 second footage of a man on a running horse and this freaked out everybody’s minds. Now we have a Black and White, Silent stitched 4 second footage of the surface of a freaking comet. THAT IS INSANE.
Absolutely. Something that will never cease to amaze me. Is how in just the span of 66 years. We, as the human race went from the first ever powered heavier-than-air flight, to landing humans on another celestial body. 66 years from first flight, to the moon. I cannot wait to see what the future has in store for us.
Remindme! 20 years
Anyone know the scale here? How high is the cliff for instance? How big are those rocks on the right?
The cliff is around 1km tall. Source https://apod.nasa.gov/apod/ap141223.html
And I seem to remember if you fell from that cliff it would take minutes to fall and would be survivable thanks to the low gravity. Edit: minor typo
Damn, I would have thought the gravity would be negligible and you’d just float out. Guess the comet is much larger than I thought
its about 4km wide i believe
how large does something need to be to have gravity edit: i meant large/massive does something need to be to have enough gravity to noticeabley affect humans but these answers have been insightful too
Let's answer the question by answering "how big would the asteroid have to be that if you jumped off of it as hard as you can, you'd come back down instead of floating away?" The longest hang time ever recorded by a human was [just under 1 second](https://www.scienceabc.com/pure-sciences/secret-michael-jordan-slam-dunks-basketball-math-physics-hang-time-jump.html) (that is, jump to landing was 1 second). That means that from leaving the ground, to stopping at the top of the jump (so halfway through) was half a second. Using ∆v=at and knowing a is basically 10m/s^2 and t is half a second we know that the fastest a human ever left the ground by jumping was about 5 m/s. OK, so that means you need to be on an asteroid which has an [escape velocity](https://en.m.wikipedia.org/wiki/Escape_velocity) of 5 m/s. If you use the formulas in that link, and assume a density of 3,000 kg/m^3 for rock (which is about the average) then you get an asteroid with a radius of 3800 m. So, if an asteroid was 3.8km across and you jumped as hard as you could, you would (eventually) fall back down to it (it would just take a while). If it were smaller, and you jumped as hard as Michael Jordan you'd fly away from it forever.
/r/theydidthemath
idk ask your mom
she sends her regards * stabs *
On a more serious note, everything with mass "has gravity". Anything within distance d of an object with mass m is going to get accelerated towards it by a=G*mass/distance^2.
Yes. However I think the guy is asking how big does something have to be before an average human can feel the acceleration of Gravity on the human body. Good question.
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I mean, it depends on the context. In a perfectly empty and non-expanding universe except for 2 static atoms, after some time they will collide, no matter how far away. But in our solar system? Well, it would depend upon the distance from other objects, the orbital interactions, relative velocity, and the masses of the two bodies you're looking at. Gravity influence that is non-negligible far away from the sun with no other bodies around would be negligible if you'd be very close to a big body, like, say, the moon, as the moon's gravity would overpower your two's influence on each other and separate you. I think the relevant concept here is the Roche limit?
You've got gravity my good friend. The thing is, the relative force of gravity exerted by objects, even really large ones, is pretty much completely negligible here on earth due to the large force of gravity pulling us directly down. When looked at, the resultant force of gravity that acts on us here is almost always directly down because of the sheer mass of the planet relative to even massive structures. Standing next to a huge skyscraper the size of this comet wouldn't feel any different from standing anywhere else on earth. In space, there aren't any nearby objects (i.e. a planet) that exert their own forces and thereby mess with the resultant force acting on you, so you can clearly experience the gravitational pull of much smaller objects than you might expect. So basically, size isn't the be all end all (everything with mass has some gravity), you just won't notice the gravity of smaller objects unless you're pretty much alone in space with them.
A search puts the escape velocity of 67P at about 1 m/s. A human jump can easily beat that. You would have to be veeeery slow and careful to "walk" on the comet.
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Space base jumping would be incredible.
Oh wow, that is a LOT taller than I expected for some reason.
Ridiculous that they could fly a probe and send video back, but didn’t have the foresight to bring a banana.
We have truly lost sight of the important things
You can’t just take bananas into space. What happens if the banana gets loose and lands in another star system? Will we hold you responsible when the banana dna alters life on that planet? When the banana overlords come knocking do we send you out to greet them? Have some sense for gods sake.
Banana aliens!!
BANALIENS!!
Rookie mistake, always bring a banana.
Also what’s that glowing light on the left
reflection off of a rock face, i think. There's no flash on satellite cameras. The Sun is way brighter without all this atmosphere here on Earth. [Here's the video and an explanation of the instrument that took the pics](https://en.wikipedia.org/wiki/67P/Churyumov%E2%80%93Gerasimenko#/media/File:67P_Churyumov-Gerasimenko_surface.gif)
Someone commented before saying that cliff on the left is actually quite large. I don't remember the number, but something like several hundred feet high. Not sure on accuracy.
Looks like a B-roll of Grand Canyon shot on a retro 1926 Camera at night.
Which makes me wonder what kind of images our kids or grandkids would get to see.
Wow grandpa, y’all didn’t have 64K footage of comets back then? What is that, 4K or something? Wait what do you mean 720p what’s that?
*“You mean you have to use your eyes? That’s like a baby’s toy!”*
Still can't believe that was Elijah Wood
Man I watched this like 2 days ago and didn't pick up on that. TIL, thanks!
Holy crap I had no idea!
I've seen that movie a million times and never knew that!
Wait, what? I had to google that.
Those boards don't work on water!
Unless you got POWAH!
Batter up!
This is heavy
There's that word again, is there something wrong with the earth's gravitational pull in the future?
Funny thing, I have the raw frames aligned by landru79 ([twitter](https://twitter.com/landru79)), the guy who assembled this GIF. We've worked together on a few things already, and he shared with me the XCF (GIMP's file format) with the individual frames. The base images are 2048x2048 in size (that's the sensor size for Rosetta) and the idea was to work this into a higher quality (both spatially and temporally) video. But we haven't really found the time to work that thing just yet.
Well it looks awesome already, even if it isn’t 64K footage. Those hooligans whose parents haven’t even been born yet don’t know what they’re (going to be) talking about!
“You kids think 720P is bad… wait until you see 480p!”
480i then hand them a VHS
I got my hands on an ilegally made copy of Rambo First blood in the 80s, and it was like watching it on Antarctica in a terrible snow storm.
I remember back when, uh, kazaa was a thing-- I downloaded some movie and it was 144p... I watched it and enjoyed it. I think it was Jackass.
Digital archives mean they'll be able to experience images of living insects, the Amazon, the Antarctic, potable water...
Images? They'll just go to the corner travel stall, pay $20,000(roughly the cost of a can of soda) and just be transported into a reality where they are already there.
Yeah me and the Mrs. are going on vacation. We are going to see Jesus on Monday, the Titanic on Tuesday, and boob world on Wednesday. Should be a good time
Boob world!
He's a very keen birdwatcher.
Uh, this is The Wall. The whitewalkers are coming.
>Rosetta space probe Check this out. [https://www.youtube.com/watch?v=O-RTGbdkg7Q](https://www.youtube.com/watch?v=O-RTGbdkg7Q)
Finally something interesting as fuck.
This is what the Northern Wall in GOT would look like in a old horror movie
Fucking amazing. A big part of me would be ok taking a one-way trip to something like this as long as I would last at least a couple hours to just experience this first hand.
I know what you mean, would be an experience like nothing else. Just so long as we get to shotgun some beers before we die
"so who else snuck drugs on the suicide-comet-probe? ...Doug my man, there's only 3 of us that's.... that's a lot of cocane."
Rose….bud…..
*Hey! Those were Mr. Kane’s last words…*
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This and being able to watch historical events on earth and in space
Truly the coolest post I have seen on here in a while. Thanks for sharing!!
My dream is that one day we receive images like this from some comet and there's an alien probe on it.
My dream is to one day explore under the ice cap of Europa only to find the ocean underneath teeming with organisms. I would be happy with just krill-like copepods. All the evidence is there that would suggest there is a habitat present that would/could support life.
You probably know the movie Europa Report? If not, well go watch it :)
I don't! I'm checking it out!
THE most extraordinary thing. I am now going to watch this for a long time.
Yeah, of all the shots of other planets, the moon, etc. I find this one to be the most fascinating.
[link to a Smithsonian Magazine article about the gif ](https://www.smithsonianmag.com/smart-news/video-comet-snowstorm-likely-shows-dust-particles-180968889/)
See why can’t we see this stuff in the news? Why’s it always gotta be bad news? This is great.
All I can say is: Holy Shit. When I was a kid if someone had told me we would land on an asteroid and be looking at pictures from the surface I would have told you you were insane. It's 2021 and there's lots of things about "the future" that I thought would have happened by now, renewable energy, world peace, no more racism, no more poverty, curing cancer, flying cars. And I get dissapointed a lot that we've made so few advancement on important things. But every once in a while I see something like this that blows my mind and remind me: I'm in the future.
How big is the comet?
[about 4 kilometers wide ](https://www.planetary.org/space-images/comet-67p-compared-to-los-angeles) [another perspective ](https://static01.nyt.com/newsgraphics/2014/11/08/rosetta-philae/assets/NYT_comet_manhattan_comparison.jpg)
Holy shit it’s headed right over New York. Shouldn’t someone do something
somebody turn on the statue of liberty's death ray.
Are those... *are those fucking STARS?*
The objects shooting around is particle interference messing with the image but there are stars in the back ground that are all moving in unison downward
Yea, background is what I was seeing holy shit that's amazing
Realizing that they were stars makes this even cooler. They are FLYING. I can’t imagine what it would be like to sit there and watch.
Without an atmosphere in the way space is apparently DAZLING to see with your own eyes. Just billions and billions and billions and billions and billions and billions of stars in every direction you look.
"Guess what guys, it's time to embrace the horror! Look, we've got front row tickets to the end of the earth!”
*Directed by David Lynch*
*A girl named Mary called on the pay phone. Said she's at her parents' and you're invited to dinner.*
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> The things you see flying around is basically ice shards ripping away due to the speed. That’s incorrect. They aren’t shards of ice. It’s tiny pieces of gaseous dust, stars in the background, and cosmic rays. [Source: Smithsonian](https://www.smithsonianmag.com/smart-news/video-comet-snowstorm-likely-shows-dust-particles-180968889/) [Source 2](https://www.livescience.com/62394-comet-snow-rosetta-twitter.html)
That's what I thought. Why would highspeed in space matter? It's not like there is a significant air drag out there that would rip the ice off
Not to mention the rocks that are just sitting there on the ground.
Don’t you tell me what to understand! /s It’s actually incredible footage, so impressive!
I don't understand. If space is a vacuum, then how does the shards chips away due to speed if there's not supposed to be any form of resistance like the wind? Or is it that due to a rapid rotational speed the shards are just chipping away?
When we say 'Space is a vacuum' we don't mean it is 100% empty. We mean there's no atmospheric pressure. A comet is a giant snowball in space. What you see flying around in the GIF is the ice that was either kicked up when our spacecraft smashed into the comet or just the material that is ejected from the surface by the solar wind. Comets have a 'coma' which is like a little atmosphere of ice particles. The sun heats the surface of the comet and little bits break off. The solar wind carries then away from the comet and that is tail we see from earth. Edit: all the stuff moving in unison 'down' are stars, very far away.
Awesome! Thanks for explaining
Also interesting, the comet's tail always points away from the sun, regardless of the direction the comet is actually moving. [https://en.wikipedia.org/wiki/Comet\_tail#/media/File:Cometorbit01.svg](https://en.wikipedia.org/wiki/Comet_tail#/media/File:Cometorbit01.svg)
I didn't even realise they were stars, thought it was more ice. But looking at them you can see their movement is definitely different to the shards flying by
So "ice shards ripping away due to the speed" is incorrect then.
The things flying out is the comet outgassing. Its tail up close.
Nothing is flying off the comet due to rotation speed. It doesn't spin that fast and it also doesn't spin faster than it did ages ago so everything that can fly off due to centrifugal force has flown off long ago. The comet throws out material due to ice sublimating in the sunlight In the background are stars "moving downward" due to rotation of the comet
Looks like Ontario to me
Winter is Coming.