Help me out: how can a "light year" be a unit of distance?

roger e bert wrote:

Wet behind the ears wrote:

Light trying to escape an event horizon can travel 0 feet in a year. Simple.

event horizon was a crappy movie

beard-seconds. Figure that one out.

Engineer 420 wrote:

Expansionologist wrote:

This is the cornerstone of expansion theory. If you observe a galaxy that is x light-years away, then every time there is a leap year it moves to x light-years + 1 light-day, ergo everything in the universe is accelerating away at the rate of 1 light-day every 4 years.

If thats the cornerstone of expansion theory, then expansion theory is for idiots. A light year is measured by the distance light travels in a vacuum in a Julian year (365.25 days), not years on a calendar.

Clearly you didn't lost your sense of humor in engineering school. Or maybe it was all that dope.

yes, a year is not 365 days sometimes and 366 days other times.

it has probably been determined to a very far decimal place.

also, whoever got on the star wars tangent, han solo was clearly trying to say how fast his ship was when he said he made the kessel run in less than 12 parsecs.

the whole sub 12 parsecs 'manuever' was just a filler for a plot hole GL made.

rupp-certified saladbar wrote:

American education in action.

Not to be a spelling nazi, but the word you want is edumacation.

Wet behind the ears wrote:

come on guys wrote:

A light year is the distance light travels in a year, it's that simple.

Light trying to escape an event horizon can travel 0 feet in a year. Simple.

Actually light is not a sentient being and cannot "try" to do anything.

Well actually wrote:

Wet behind the ears wrote:

Light trying to escape an event horizon can travel 0 feet in a year. Simple.

Actually light is not a sentient being and cannot "try" to do anything.

Also, isn't a year (or any other unit of time) literally meaningless within an event horizon?

Carted Away wrote:

I'm pretty sure it's still the water that's wet in that scenario chief. The acid is just dissolved in it, just like the vast majority of water you'll encounter in the world has stuff dissolved in it.

Liquid nitrogen would be a better example, or for a room temperature version mercury. Both not advisable for feeling what their 'wetness' is like.

Nope, olive oil will create a "wet" sensation on your skin like most all liquids. Liquid mercury doesn't have similar properties as water. It has higher surface tension vs water and will coagulate rather than coat most surfaces. Therefore it is not a good comparison nor is liquid nitrogen because it is extremely cold and will freeze your skin on contact.

Are you the guy who posted about how to tell if you are mentally challenged?

elkem wrote:

I don't get it. You're telling me a year is a unit of distance? What am I missing?

How long does it take light to reach Uranus?

elkem wrote:

I don't get it. You're telling me a year is a unit of distance? What am I missing?

Let me illuminate you: what about four Bannister's minutes? Would you understand that as a measure of distance?... that is one mile, in case you're not illuminated enough.

Physicists, by the way, are not trying to be fancy by defining distance in light years. One of the most important scientific discoveries of the last century was that time and distance are one and the same, in some sense (Einstein's general relativity). It's a very important concept. Should be common knowledge, if threads asking why intelligence is frowned upon in the US (and not only in the US) were not, unfortunately, having a valid point.

Time and distance being tangles up means also, in some way, that the distance Bolt runs for 100 meters is not the distance a dude from The Biggest Looser would run for a 100 meter - I think, too long since I was doing those HW.

hard to believe wrote:

elkem wrote:

I don't get it. You're telling me a year is a unit of distance? What am I missing?

How long does it take light to reach Uranus?

There we go! The ol' Uranus trope. Nothing finer or funnier. Now the thread can end with dignity.

I've never heard that Kessel run explanation before but I like it. However Han Solo said "It's the ship that made the Kessel run in less than 12 parsecs." He wasn't talking abuot his recklessness or skills as a pilot but boasting of the speed of the Falcon. I think he said it after Luke called the Falcon a piece of junk.

if han solo is talking about covering some obstacle course or path (Kessel run?) in less than 12 parsecs, then he is implying the ship has a close-to-the-speed-of-light velocity, because a parsec is a unit of distance, and if they are using the contaction of a distance as a way of measuring the speed of an object, then the object must be moving close to the speed of light. that's an interesting way of putting it i guess.

here's a mind trip:

if time is dialated as an object approaches the speed of light, then does a photon in a vacuum ever experience time? if so, is it because it is never going exactly the speed of light since it does have some mass?

bangalangadanga wrote:

yes, a year is not 365 days sometimes and 366 days other times.

it has probably been determined to a very far decimal place.

also, whoever got on the star wars tangent, han solo was clearly trying to say how fast his ship was when he said he made the kessel run in less than 12 parsecs.

the whole sub 12 parsecs 'manuever' was just a filler for a plot hole GL made.

A year is approximately 365.24 days, hence the calendar year adjustment every 4 years.

In addition there is an occasional 1 second adjustment.

Engineer 420 wrote:

Expansionologist wrote:

This is the cornerstone of expansion theory. If you observe a galaxy that is x light-years away, then every time there is a leap year it moves to x light-years + 1 light-day, ergo everything in the universe is accelerating away at the rate of 1 light-day every 4 years.

If thats the cornerstone of expansion theory, then expansion theory is for idiots. A light year is measured by the distance light travels in a vacuum in a Julian year (365.25 days), not years on a calendar.

It was a joke..

This coming from someone who has 'salad bar' as a single word...

rupp-certified saladbar wrote:

American education in action.

The other interesting thing is that a year itself is defined defined based on distance, the distance covered by the Earth going all the way around the sun. In other words, a light year is how far light goes in the same time goes it takes the Earth to go around the sun.

A hicham 3:43 or a bannister 3:59=1mile

A rudisha 1:40.9 or makloufi 1:43=800m

A Usain 9.58=100m

Yea, go 3 bannister 3:59.4s south then make a right and go 5 usain 9.58s west. It's on your left.

Gotta rewrite the road signs if they PR.

Fellas... is it PETS-MART or PET-SMART?