Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

If the moon were only 1 pixel: A tediously accurate solar system model (2014)

joshworth.com

Post reply on HN
Print view View original

221–230 of 273 posts

Re: If the moon were only 1 pixel: A tediously accurate solar system model (2014)

#221

Post by the_af »

johnnyjeans wrote: post #117
amelius wrote: post #3

Make sure you press the "c" button in the bottom right. Light is incredibly slow, and everything seems out of reach. I think we'll have a holodeck before we reach another star. And maybe that'll be enough.

Is light slow? Or is the human perception of time just scaled down as a result of our rapid metabolism and infinitesimality? People historically mistake plants for being inanimate things with no reactivity, that they are far more simple and stupid than they truly are. Outside of a few exotic examples, plants simply operate on a wider timescale that's basically imperceptible without careful and particular observation.…

> Is light slow? Or is the human perception of time just scaled down as a result of our rapid metabolism and infinitesimality?

It's slow for humans to explore the cosmos.

"Slow" is meaningless without a frame of reference, and "humans" seems like a good frame of reference, since it's us -- and not plants or stars -- who are writing on HN to discuss this.

Because it's us, humans discussing this in HN, the frame of reference is implied and it's not necessary to spell it out.

Re: If the moon were only 1 pixel: A tediously accurate solar system model (2014)

#223

Post by computator »

Given the great distances and how small the planets seem at that scale, I'm surprised that we can see any of the planets with the naked eye. Thinking about Jupiter, it's 140K km in diameter and about 629M km from Earth. That's a ratio of 1:4500. So imagine a U.S. dime that is 1.8cm in diameter placed 1.8 x 4500 = 8100 cm away. Would you be able to see a dime that it 81m or 266ft away at nighttime, assuming it slightly illuminated? We can see Jupiter, so I guess we should be able to see the illuminated dime too.

Re: If the moon were only 1 pixel: A tediously accurate solar system model (2014)

#224

Post by dbetteridge »

tridentboy wrote: post #178
chrisweekly wrote: post #174

Earlier quoted context omitted.

> "A photon instantly travels to the end of time" Please explain this. TIA

First set gamma as being 1/sqrt(1-v^2/c^2), with "c" being the speed of light. The factor for time dilation and distance contraction in special relativity is gamma and 1/gamma respectively. That means that when you get to speeds equal to c, your time runs infinitely slower and the distances are infinitely shorter. So if your clock is infinitely slower, so every travel at "c" speeds means that no time passes for you.…

Follow up question from someone who's mostly forgotten his university physics.

Do photons actually exist, in the traditional sense of physical matter.

Or are they just a convenient short hand to describe the transfer of energy via waves in the fabric or space time, if they dont experience the universe when passing through it but only when interacting with matter and matters "dents" in space-time.

Re: If the moon were only 1 pixel: A tediously accurate solar system model (2014)

#225

Post by lenkite »

ifa_ wrote: post #211
johnnyjeans wrote: post #117

Earlier quoted context omitted.

Is light slow? Or is the human perception of time just scaled down as a result of our rapid metabolism and infinitesimality? People historically mistake plants for being inanimate things with no reactivity, that they are far more simple and stupid than they truly are. Outside of a few exotic examples, plants simply operate on a wider timescale that's basically imperceptible without careful and particular observation.…

yeah light _is_ actually pretty slow and we hit that in networking and optics pretty often if iirc. like not even on a human level, universally even on a grand scale the speed of light is almost torturously slow, there’s nothing philosophical about it

Might have been a deliberate rule enforced on the universe to avoid interstellar wars between sapient civilizations.

Re: If the moon were only 1 pixel: A tediously accurate solar system model (2014)

#226

Post by UltraSane »

amelius wrote: post #3

Make sure you press the "c" button in the bottom right. Light is incredibly slow, and everything seems out of reach. I think we'll have a holodeck before we reach another star. And maybe that'll be enough.

Stephen Baxter wrote a story named The Gravity Mine about the descendants of humanity living after all stars have died. They get energy from black holes but even they are starting to noticeably shrink. Their perception of time is billions of times slower than humans and the upshot of this is that the speed of light would actually seem pretty fast.

https://www.infinityplus.co.uk/stories/gravitymine.htm

Re: If the moon were only 1 pixel: A tediously accurate solar system model (2014)

#227

Post by UltraSane »

munksbeer wrote: post #9
amelius wrote: post #3

Make sure you press the "c" button in the bottom right. Light is incredibly slow, and everything seems out of reach. I think we'll have a holodeck before we reach another star. And maybe that'll be enough.

> Light is incredibly slow, and everything seems out of reach. Yes, agreed. I find it a little depressing. An unimaginably huge universe, tantalisingly there, but completely out of reach.

Not if you are an immortal AI or uploaded human.

Re: If the moon were only 1 pixel: A tediously accurate solar system model (2014)

#228

Post by DiggyJohnson »

btilly wrote: post #167
eslaught wrote: post #131

Earlier quoted context omitted.

One thing I've always wondered is what fraction of c is actually realistically achievable with current technologies? (Maybe with scenarios for manned/unmanned spacecraft.) Like are we at 0.1% or 0.01% or more orders of magnitude off?

If you enjoy such questions, I highly recommend https://www.amazon.com/Indistinguishable-Magic-Robert-L-Forw... . The best speed for interstellar travel with technologies that current theory says should be within our reach can be achieved with a vehicle with a light sail pushed by a giant laser, that is powered by solar power. There is even a way to brake it when it reaches the target star. I forget what the predicte…

Slow down by pulling on the fishing line tied to the back of it, carefully.

Re: If the moon were only 1 pixel: A tediously accurate solar system model (2014)

#229

Post by btilly »

DiggyJohnson wrote: post #228
btilly wrote: post #167

Earlier quoted context omitted.

If you enjoy such questions, I highly recommend https://www.amazon.com/Indistinguishable-Magic-Robert-L-Forw... . The best speed for interstellar travel with technologies that current theory says should be within our reach can be achieved with a vehicle with a light sail pushed by a giant laser, that is powered by solar power. There is even a way to brake it when it reaches the target star. I forget what the predicte…

Slow down by pulling on the fishing line tied to the back of it, carefully.

It slows down by releasing a large light sail in front of it, designed to reflect light back to a much smaller light sail behind it. The laser then pushes the large sail away, and as the sail goes it pushes the smaller sail (and ship) back. This leaves the ship at moderate speed relative to the new star, and a large sail traveling very, very quickly beyond it.

We do not yet have this technology. But we can show that it is plausible.

Post reply on HN