[HN Gopher] Earth Received a Message Laser-Beamed from 10M Miles...
___________________________________________________________________
Earth Received a Message Laser-Beamed from 10M Miles Away in NASA
Test
Author : hackernj
Score : 60 points
Date : 2024-03-17 07:04 UTC (15 hours ago)
(HTM) web link (www.sciencealert.com)
(TXT) w3m dump (www.sciencealert.com)
| tosh wrote:
| > the laser photons took about 50 seconds to get from spacecraft
| to telescope
| dr_dshiv wrote:
| >If we're going to eventually be able to send high-definition
| video messages to and from Mars without a significant delay, then
| this is a step towards the tech we need.
|
| Won't all Mars messages have a significant delay due to the speed
| of light more than bandwidth?
| mr_sturd wrote:
| In the case of Perseverance, I think data has to be sent in
| batches to a relay satellite and the forwarded back to Earth.
| That time when the satellite has line-of-sight with the rover
| is short, before the signal is lost, and it has to wait before
| continuing.
|
| It'll mean more data can be sent in these batches from what I
| understand.
| thrance wrote:
| I think they meant "more significant than it need to be".
|
| Recently I looked up how long it takes light to go to Mars from
| Earth : it's between 3 and 20 minutes depending on their
| relative positions.
| mytailorisrich wrote:
| That's my interpretation as well.
|
| Traditionally deep space bandwidth is low so that sending
| huge amount of data takes a long time in addition to time of
| travel.
| sneak wrote:
| Yup, no realtime communications of any sort, even texting,
| with people living in the Mars cities. I think living in the
| moon will be much more attractive to people, given that you
| can still have video/voice calls with a slight lag (2600ms
| roundtrip) and text conversations with no perceptible latency
| increase (vs ones to people still on Earth).
| dotnet00 wrote:
| Personally I don't think an up to 20-40 minute lag for
| communications will be that big of a deal, it'll take a bit
| of getting used to, plus mechanisms to synchronize internet
| data with Earth, but we're pretty used to asynchronous
| communications, and prior to the advent of electricity, not
| having realtime communication over large distances was
| normal and tolerable.
| thfuran wrote:
| >plus mechanisms to synchronize internet data with Earth
|
| Even in a future where there's a city on Mars, that seems
| unlikely.
| dotnet00 wrote:
| I disagree, long term I think we'd have at least a
| significant portion of internet data synchronized between
| the two. Of course early on it'd probably just be in the
| form of certain popular entertainment sources and
| informational resources being periodically uploaded from
| Earth, more akin to a Plex or Invidious server and
| Wikipedia backup for Mars.
|
| But as the size of a colony grows, it just makes more and
| more sense to sync up as much data as possible. Eg a
| YouTube Mars which downlinks ahead of time trending
| videos + videos from people subscribed to by Martians +
| videos the algorithm thinks Martians will like and
| uplinks the same stuff for Earth.
| thfuran wrote:
| Some very small subset is perhaps plausible, but I think
| you're overestimating how much Google or Netflix would
| care about addressing a small and inconvenient market.
| sneak wrote:
| A major self-sustaining colony on Mars will probably take
| 50-100 years, at which point Google as well as its
| current jurisdiction of registration (Delaware) will
| likely both be history.
| thfuran wrote:
| Self-sustaining? I think that's far enough out that is
| basically pointless to speculate a deadline. It would
| require too many breakthroughs.
| mewpmewp2 wrote:
| Maybe you can get an AI agent for both of you who knows
| how to perfectly simulate you in a dialogue or predict to
| great accuracy what you would say on both sides.
| mikhailt wrote:
| Deleted due to incorrect understanding.
| Evidlo wrote:
| Faster-than-light communication of any sort breaks
| causality and is not permitted by physics.
|
| Quantum entanglement does not allow you to communicate.
| It just means two particles have a linked but random
| state.
| thecosmicfrog wrote:
| This is why Star Trek uses "subspace" as a plot handwavium[1]
| to explain how a starship can hail Earth from hundreds of
| lightyears away with seemingly no latency.
|
| [1] handwavium, my favourite new word:
| https://www.urbandictionary.com/define.php?term=handwavium
| macintux wrote:
| For some illogical reason I never had a problem with sending
| messages across such vast distances, but when the Enterprise
| detected another ship starting its engines from a light year
| away my suspension of disbelief collapsed.
| jryb wrote:
| Easy fix: subspace-based sensors. If the other ship is
| transmitting in any way, or its engine produces visible
| artifacts in the subspace field, it could be detected.
| sigmoid10 wrote:
| You're mixing up two concepts here: Bandwidth and latency
| (ping). Latency will always be limited by the speed of light,
| but bandwidth is currently limited by radio transmission. The
| upload speed for rovers like Curiosity and Perseverance peaks
| at like 2000kb/s tops under ideal conditions and is also
| limited to a few minutes at a time when the relay orbiter is in
| the right position. With lasers, bandwidth is measured in
| hundreds of Gb/s. That's the difference between sending an
| image in less than a second vs. having to wait a day.
| fallingknife wrote:
| This will get us to Mars orbit, but don't we have to go to
| radio anyway to relay through the atmosphere to the surface?
| sigmoid10 wrote:
| Mars atmosphere can barely be called that. It's less than
| one percent of earth's pressure. People just have a wrong
| perception of it because of wildly inaccurate depictions in
| movies like The Martian. And even if you want to transmit
| using radio between the surface and low orbit, it's far
| less of a bandwidth issue than transmitting over millions
| of kilometers. Deep space transmissions of the future will
| use optical wavelengths instead of radio, there's no
| question about it.
| estiaan wrote:
| It's not just the atmosphere that's an issue though,
| having a laser in earth's orbit track something on mars'
| surface and vice versa would require some incredible
| tracking, it would be easier to go from orbit to orbit
| sigmoid10 wrote:
| It's not that hard with modern electronics. Telescopes
| with adaptive optics have been doing that since the 90s.
| Also beware that a laser doesn't remain perfectly
| coherent over many kilometers (let alone millions). So
| it's not like you need to perfectly hit a satellite dish
| area of a few m^2 on the surface of mars from earth. It's
| not really any harder to do from the surface than from
| orbit. In fact it might actually be easier since you
| don't just have to account for the rotation and orbit of
| earth but also for the orbital velocity of the relay.
| LoveMortuus wrote:
| Aren't photos and radio waves basically the same thing?
|
| I guess the only issue that could happen is the scattering
| due to atmosphere, but as others have noted it's barely
| existent.
| perihelions wrote:
| The laser experiment in the OP terminated at a ground-based
| optical telescope in California.
|
| If you wanted a solution robust against clouds, I don't
| know if it'd make more sense to have a optical->radio relay
| satellite in earth orbit, or to have a redundant network of
| ground-based optical receivers in multiple places.
|
| (There's a quirk of physics that transmitting and receiving
| aren't symmetric in these setups. All of the atmospheric
| distortion happens in the few kilometers of atmosphere, out
| of tens of millions of km path lengths. Because the angular
| distortion happens at the start of their optical paths,
| laser signals going from Earth-outwards will have much
| larger absolute distortions, than signals being received on
| Earth from space).
| tres wrote:
| Relevant quote: "Never underestimate the bandwidth of a
| station wagon full of tapes hurtling down the highway." --
| Andrew S. Tanenbaum
| mewpmewp2 wrote:
| How is he mixing up concepts there? Due to light speed
| bottleneck you would literally always have at least 3 minute
| delay unless you break the physics, in some way. So the ping
| would always be at least 6 minutes. 3 minutes is quite a
| significant delay for any sort of comms. Video or otherwise.
|
| If anyone is mixing up concepts, it seems to be the article
| author to me, mixing up speed width bandwidth.
| farmdve wrote:
| It will. It always will, no technology on Earth now or likely
| in the future allow this to change. The only thing that will
| change is bandwidth or how much data can be sent at once.
| thfuran wrote:
| Yes, and that changes how long you have to wait for a fixed
| amount of data to arrive, especially when transmission
| windows are narrow and sufficiently low bandwidth would mean
| having to waste time waiting between several.
| mewpmewp2 wrote:
| But the delay will always be significant either way.
| rasz wrote:
| In time we might find ways to glitch the simulation.
| IIAOPSW wrote:
| Yeah, but the throughput will be incredible.
| rmbyrro wrote:
| For a moment I deluded myself that this was SETI news, but was
| skeptical due to the proximity. It's so terrifying that no one's
| out there after billions of years and billions of star systems in
| the galaxy only.
| sigmoid10 wrote:
| Well, the headline is probably intentionally slightly
| misleading in that way. But it'll only fish certain people,
| because 10 million miles will only sound far if you know
| nothing about space.
| sven_8127642 wrote:
| There's certainly intelligent life out there. It definitely is
| horrifying that in the current age there's been no contact
| with, as you mentioned, billions of years of time spanned
| across the galaxy and billions of systems out there.
|
| You also have to think that we're occupying such a small
| portion of our species existence. There's hundreds of thousands
| of years of human history we just have zero record of. During
| that course of time, we have no way of knowing if there WERE
| attempts of advanced life to contact our planet/species, only
| for them to find (presumed) low intelligence or no means of
| advanced communications.
|
| Maybe we'll be fortunate enough to experience whispers of proof
| in our lifetimes, but I imagine it'll be in the next few
| thousands of years if we can manage to remain relevant
| technology wise before CC cooks us.
| nyokodo wrote:
| > There's certainly intelligent life out there... > Maybe
| we'll be fortunate enough to experience whispers of proof in
| our lifetimes
|
| Certainty without evidence is faith. There's nothing wrong
| with that exactly, I just like to point it out for the crowd,
| that may not include you, who judge other faiths for the same
| unavoidable human behavior that they blatantly and
| hypocritically indulge in.
| thfuran wrote:
| Why is that terrifying?
| CooCooCaCha wrote:
| Loneliness is creepy, it begs the question of why we can't
| find anyone else out there and the answer to that question
| leads to existential dread and fear.
|
| Why does life seem so rare? Especially since we've been able
| to find so many planets that seem habitable.
|
| Is it hard to jumpstart life? Or have there been many planets
| with intelligent life and almost all of them die out for some
| reason? Maybe technology is far more limited than our
| imaginations would like to believe and we don't hear from
| anyone else because it's impossible.
|
| Lots of thoughts here that don't sit well with most people.
| mewpmewp2 wrote:
| Not sure if I deluded myself, but the title did seem
| intentionally worded for this reason so I definitely cringed.
| nullhole wrote:
| Should have a (2023) on this, I think.
|
| The article says "An earlier version of this article was
| published in November 2023."
___________________________________________________________________
(page generated 2024-03-17 23:02 UTC)