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Nasa's Voyager 2 probe 'leaves the Solar System'
- saagarjha 8y agoRelevant xkcd: https://xkcd.com/1189/ https://xkcd.com/1189/
- tokai 8y agoyeah they can keep writing these articles til we're all dead.
- jessriedel 8y agoOf course, that comic's about all the times and ways in which Voyager 1 has left this solar system. We've got decades of hearing about Voyager 2 ahead of us!
- lmilcin 8y agoThere actually isn't anything strange about it leaving solar system multiple times when the heliopause recedes towards Sol and then expands forward again enveloping the craft.
- neaden 8y agoWell it's also that we have multiple ways of defining the border of the solar system.
- lmilcin 8y agoSure, you can say that the Solar system ends where it stops being gravitationally dominant. But think about this, we say we left Earth for space when we actually leave Earth's atmosphere. When you cross heliopause you are actually leaving "atmosphere" of solar system. Within it it is dominated by the particles from solar wind. And the change is very abrupt and well defined (but only in the direction of the motion of the Solar system, ie. where Voyagers are) in contrast to how Earth's atmosphere just gradually thins out and we have to get into some sort of agreement when it actually ends.
- deleted 8y ago[deleted]
- shshhdhs 8y ago> Voyager 1 departed Earth on 5 September 1977, a few days after its sister spacecraft, Voyager 2. Well that’s unusual isn’t it? Perhaps there was a temporary issue/delay with #1? I didn’t see the explanation in the article.
- weberc2 8y agoIIRC Voyager 1 traveled faster than Voyager 2, so it quickly passed Voyager 2. They named it Voyager 1 because it was going to arrive on target sooner.
- jessriedel 8y ago> They named it Voyager 1 because it was going to arrive on target sooner. Do you know this or are you speculating?
- scrumbledober 8y agoI don't have a source but I remember this being a known fact.
- UI_at_80x24 8y agoIt is known Khaleesi.
- jeffbax 8y agoIf you haven't watched it yet, "The Farthest: Voyager in Space" is an incredibly great documentary recently released by PBS https://www.netflix.com/title/80204377 https://www.netflix.com/title/80204377
- krylon 8y agoCannot watch from Germany. :(
- matte_black 8y agoVPN
- mrsteveman1 8y agoIt's probably still available in your region as a $2 rental from one of the other streaming services, and would be well worth it.
- arendtio 8y agohttps://www.werstreamt.es/film/details/1521627/the-farthest/ https://www.werstreamt.es/film/details/1521627/the-farthest/
- hanoz 8y agoThanks. I just Googled this, expecting it to be hard to get hold of in the UK, but was delighted to discover it was broadcast on BBC Four last night and is therefore available on iPlayer for the next 30 days. Looking forward to that.
- eecc 8y agoNetflix? Can't even browse the catalog without signing up first. iTunes? No results PBS? Not available due to rights restrictions. Pirate Bay? Hmm...
- jeffbax 8y agohttp://www.pbs.org/the-farthest/home/ http://www.pbs.org/the-farthest/home/
- japhyr 8y agoMy all-time favorite graph is the plot of incident solar particles on Voyager 1 in 2012 [0][1]. That to me is the perfect image of scientific thinking. "We anticipate that the probe will enter interstellar space and see a significant drop in the number of incident solar particles." And then it happens, clear as day. I teach high school math and science, and I have shown this graph to students every year. Many students get what this really means. They suddenly understand how far Voyager is from us, and how small and isolated our solar system really is in the universe. Now it will be fun to show them the same graph from Voyager 2 [2][3]! [0] https://3c1703fe8d.site.internapcdn.net/newman/gfx/news/hires/2012/jyguyg.jpg https://3c1703fe8d.site.internapcdn.net/newman/gfx/news/hire... [1] https://phys.org/news/2012-10-voyager-left-solar.html https://phys.org/news/2012-10-voyager-left-solar.html [2] http://earth-chronicles.com/wp-content/uploads/2018/11/voyazh.png http://earth-chronicles.com/wp-content/uploads/2018/11/voyaz... [3] http://earth-chronicles.com/space/voyager-2-is-even-closer-to-the-border-of-the-solar-system.html http://earth-chronicles.com/space/voyager-2-is-even-closer-t...
- simulate 8y agoThanks for these graphs! Your Voyager 1 graph [footnote 0, in the parent comment] shows two periods of particles-per-second drops to around 10 particles per second followed by a rebound and then a dramatic drop to 2 to 3 particles per second. The Voyager 2 graph [footnote 2, in the parent comment] shows a single drop to around 17 to 18 particles per second and what looks like the beginning of a rebound. Wouldn't interstellar space be characterized by the drop to below 3 particles per second? Is this the same issue we had with Voyager 1 where Voyager 2 is beginning the process of entering interstellar space but has not yet actually entered it? If not, why are the particle counts about an order-of-magnitude higher for Voyager 2 then they were for Voyager 1 in interstellar space?
- 21 8y ago> why are the particle counts about an order-of-magnitude higher for Voyager 2 then they were for Voyager 1 in interstellar space Better detector? Those are detected particle counts
- swarnie_ 8y agoQuote from the article: "the US space agency says that Voyager 2 has a working instrument aboard that will provide "first-of-its-kind observations of the nature of this gateway into interstellar space"." Does anyone know what Voyager 2 is carrying that Voyager 1 wasn't that might give interesting data in this part of space?
- lordnacho 8y agoHow do they manage to keep sending data back? Is there a really really directional antenna that points at the Earth?
- mbell 8y agoPretty much. The big dish on the voyagers is the comms antenna, not a science instrument.
- imglorp 8y agoThis guy goes into great depth at an EE and signals level on how the Deep Space Network does this. https://www.youtube.com/watch?v=FzRP1qdwPKw https://www.youtube.com/watch?v=FzRP1qdwPKw
- lalaithion 8y agoAnd we have giant antennas that listen.
- aaaaaaaaaab 8y agoYes. Direction + a large enough receiver on Earth. Oh, and lots of error correction.
- mlindner 8y agoYes. Directional antenna with EXTREMELY low bitrates so that the bits have a long time to accumulate any noise out of the signal. Specifically its at 160 bits per second at a transmit frequency of 8 GHz.
- jfries 8y ago160 bits per second is actually pretty high. As comparison the German radio time signal used by parts of Europe sends out 1 bit per second: https://en.wikipedia.org/wiki/DCF77 https://en.wikipedia.org/wiki/DCF77
- Sharlin 8y agoYeah, at the time the probes were launched, 160bps would have been a fairly respectable transmit rate between two computers connected by a cable, located in the same city!
- stewbrew 8y agoThis is great and everything but is there really a need to get this status report every year. If so, shouldn't it rather read: still leaving the Solar System?
- davidcuddeback 8y agoYou're thinking Voyager 1, which left the solar system in 2012. This is reporting on Voyager 2.
- stewbrew 8y agoErm, well that's possible. Anyway I still think less would have been more: https://hn.algolia.com/?query=%22Voyager%202%22&sort=byDate&prefix&page=0&dateRange=all&type=story https://hn.algolia.com/?query=%22Voyager%202%22&sort=byDate&...
- kwoff 8y agoThey should send these out every decade or so. Especially if they could get to where they can relay data from probes further out. Technology advances so quickly, after all.
- alluro2 8y agoYeah, as well as visit Titan and Europa more seriously...Why "we" don't do such things that are silly inexpensive relatively, but burn millions on reality shows is something I'll never learn to accept...
- nabla9 8y agoPure science missions must compete for funding against efforts that inspire and capture the imagination of the people. Getting humans into Mars to study Mars geology is priority. Once humans have been in Mars few times and the public interest vanishes–as it did during moon missions–there may be more money for telescopes and probes and cheaper robotic exploration. 53 million households in the US (over 580 million globally) watched the Apollo 11. The numbers dropped dramatically after the first mission. Apollo 13 was dramatic exception. People get bored easily and lose intrest. --- If I would have a say, the priority should be the Overwhelmingly Large Telescope (OLT). US and other countries should have joined with Europeans to make it happen. The cost was 'just' 1.5 billion. Europeans opted for Extremely Large Telescope (ELT) instead and US is dong thirty meter telsecope. OLT would have been really something.
- ahje 8y ago
- jpmattia 8y agoAnyone happen to know if the Voyager's energy is such to exceed escape velocity wrt sun?
- DavidSJ 8y agoYep, it and four other spacecraft. https://wikipedia.org/wiki/Interstellar_probe https://wikipedia.org/wiki/Interstellar_probe
- raquo 8y agoVoyager 2 has been "leaving the Solar System" regularly for quite a while now. Example from 2007: https://www.nature.com/news/2007/071210/full/news.2007.365.html https://www.nature.com/news/2007/071210/full/news.2007.365.h... I guess the actual thresholds crossed are different but at this point who cares, unless you actually know those thresholds. It's out there and getting farther out. Yay. If you can't describe an achievement without sensationalizing the hell out of it for the Nth time, maybe don't describe it.
- deleted 8y ago[deleted]
- quickthrower2 8y agoVoyager 2 is leaving the atmosphere!
- m3at 8y agoSomeone has been counting: https://m.xkcd.com/1189/ https://m.xkcd.com/1189/
- ohiovr 8y agoI was wondering if I had deja vue over the probe leaving the solar system.
- gadders 8y agoI came here to say this. I was sure I had read it before.
- celias 8y agoIn some sense the Voyager spacecraft have been leaving the solar system since launch. :) As the Nature article points out, Voyager 2 crossed the termination shock in 2007, entering the heliosheath. The recent announcement is about Voyager 2 exiting the heliosphere and entering interstellar space. Here's a nice graphic that shows the various regions - https://www.nasa.gov/sites/default/files/thumbnails/image/pia22835a_20181206_voyager_in_interstellar_space_annotated_1920x1080_72dpi-final.png https://www.nasa.gov/sites/default/files/thumbnails/image/pi...
- listic 8y agoHave we been able to launch faster spacecraft since? I'm thinking whether there could potentially be a newer interstellar probe that could overtake the Voyagers 1 and 2 on the way out of the Solar system.
- hobbes78 8y agoOnly five probes were launched with the ability to leave de Solar System, but the Voyagers are still the fastest ones... https://en.wikipedia.org/wiki/List_of_artificial_objects_leaving_the_Solar_System https://en.wikipedia.org/wiki/List_of_artificial_objects_lea...
- lodi 8y agoNot really, no. These probes don't really accelerate by burning fuel; instead they pick up velocity by doing a bunch of gravity assists. The more of these you do, the faster you go, but sometimes you have to coast around the sun for years to align yourself with the next gravity assist, and this gets worse and worse until you hit solar escape velocity. Using this method, your final interstellar velocity will just depend on how many objects you can slingshot around on your final 'kick' out of the solar system. (So, in other words, you can get in the same ballpark as Voyager, but not orders of magnitude faster.) Here's a video of what it takes "simply" to get out near Jupiter, nevermind out of the solar system. https://www.youtube.com/watch?v=ktrtvCvZb28 https://www.youtube.com/watch?v=ktrtvCvZb28 The Voyager spacecraft took advantage of a special planetary alignment that won't happen again for over a hundred years. --- Having said that, if by 'spacecraft' you mean something weighing a few grams, the Starshot program might be able to obliterate the Voyager records. https://en.wikipedia.org/wiki/Breakthrough_Starshot https://en.wikipedia.org/wiki/Breakthrough_Starshot
- koheripbal 8y ago> a laser with a gigawatt of power (approximately the output of a large nuclear plant) would provide only a few newtons of thrust. wow... that's not very efficient...
- kartickv 8y ago
- a_rahmanshah 8y agoAgain?
- jmts 8y agoI had the same initial reaction. This time it's Voyager 2, not Voyager 1. And the term 'leaves the solar system' is moderately misleading. See my initial response: https://news.ycombinator.com/item?id=18650987 https://news.ycombinator.com/item?id=18650987
- kalimatas 8y ago> Voyager 1 will not approach another star for nearly 40,000 years That's a lonely ride...
- syntaxing 8y agoHow much of a lag is there in the data transmission? I guess that should correspond to how many light years it is away? How does the probe know which direction to send the data? I have so many questions! I gotta watch that documentary and listen to the podcast people are suggesting here!
- rlanday 8y agoThe current one way transmission times are 20 hours and 5 minutes to Voyager 1 and 16 hours and 38 minutes to Voyager 2: https://voyager.jpl.nasa.gov/mission/status/ https://voyager.jpl.nasa.gov/mission/status/ The probes use a star tracker to determine their orientation (they apparently look for the sun and one other star). I assume they keep track of their expected position in the solar system, and this is fine-tuned with updates from the ground station. If you have position and orientation, you can compute where the Earth should be at the current time and point the antenna in that direction.
- lodi 8y ago"Light years" is a bit optimistic. Voyager 1 is about 20 light-hours away (144 times further from the sun than we are). https://voyager.jpl.nasa.gov/mission/status/ https://voyager.jpl.nasa.gov/mission/status/
- joshlegs 8y agoyou know, it's pretty damn incredible that we've sent little tiny space probes out of our solar system and they can still talk to us. sometimes i like imagining this tiny ball of circuits floating in space talking to its home planet and it just boggles my mind.
- garysahota93 8y agoToo soon to make a "one small step" joke?
- pascalxus 8y agojust to be clear, it hasn't "left the solar system", it left the heliosphere. They said it still needs to leave the OOrt cloud before it has officially "left the solar system". but, it's cool that it will continue transmitting until about 2027!
- russellbeattie 8y agoWhat always amazes me is the vast difference between the visual and non-visual effect of the sun. From that distance, the sun is just another glowing speck in the distance, and yet its gravity and radiation is still felt. Like if you had a speaker the size of a pinhead that you could hear from a mile away. (Or probably a lot more).
- Sharlin 8y agoWell, the probes definitely "feel" the visible radiation of the sun as well, for some definition of "feel". At that distance the sun is still much brighter than any other star, and it would be obvious in photos if they still had use of their cameras.
- dmurray 8y agoEven brighter than you might think. Based on the reasoning in this Quora answer [0], which looks reasonable at first glance, it's 10-20 times brighter than a full moon on Earth. If you were out there sitting on Voyager 2, you could read a book by sunlight. [0]https://www.quora.com/How-bright-is-the-sun-to-the-Voyager-spacecraft-now https://www.quora.com/How-bright-is-the-sun-to-the-Voyager-s...
- holoduke 8y agoDo we actually know where they end up? Is it possible to make a reliable calculation on their trajectory in let's say 50.000 years? Do they get locked in a next solar system or will they continuesly be catapulted between systems? They are not solar powered right? So they won't be powered up again when reaching a next star (assuming all electronics are still alive)
- Sharlin 8y agoNeither probe is headed towards any particular star. In roughly 40,000 years each will pass a small nearby star (Gliese 445 and Ross 248 for V1 and V2 respectively) at a distance of over 1ly, far too distant for the stars to have much effect on the trajectory of the probes. Barring any chance encounters, the spacecraft will be drifting in the interstellar space for a very, very long time.
- lholden 8y agoThe big news is that Voyager 2 should be experiencing more interstellar medium than atmosphere from our star at this point. It will still be a while before it could be said to truly "leave the Solar System" if you consider gravitational influence to be a factor. There are objects still orbiting our star at more than a light year away for example (Oort cloud).