Coruscant's Surface Gravity and Radius

Hardy · Post by **Hardy** » 2004-12-22 08:42pm

Coruscant represents the standard for galactic living, and technology should be designed for operation in gravities like Coruscant's. Deriving Coruscant's surface gravity would therefore be essential for use in calculations involving gravity. Plus it's far better than presupposing that the surface gravity of every planet in SW is 9.81m/s².

It would be helpful to have some examples of freefall on Coruscant with measurable distances and fall times. Or if freefall is not available, one could measure the velocity that an object is thrown up and the distance it travels to come down or the time it takes to come down.

I am aware of Anakin and Obi-Wan's freefalls in AOTC, but their distances are not entirely measureable. However, it is possible to measure their acceleration on smaller scales(frame-by-frame). (Though they do serve to produce a lower limit estimation of the height of Coruscant's buildings.) The explosion on the landing pad in the beginning of AOTC can be useful and measurements of fall times and distances can be very precise. Anakin's speeder crash and Obi-Wan's leap from Padme's window are also good examples.

To calculate gravity:
g=v²/2d
g=2d/t²
g=v/t

Coruscant's radius is important if one wants to calculate the planet's mass, orbital parameters, and a multitude of other parameters.
It can be derived from measurements of the distance to the horizon. The height of the Jedi Council Chamber, for example, can be scaled and the distance to the horizon from the chamber can(in theory) be measured by looking at the distribution and size of roads and buildings. Parallax may or may not be a possibility.

But if one has the distance to the horizon and the height of the camera, they can plug into:
r=1/2(d²/h)

I am aware of(it's my favorite page on SWTC) Dr. Saxton's derivations from role-playing guides, but canon estimates would seem far more valid.

It's unfortunate that I don't have the prequels available to perform such a survey, however.

Are there any other methods?

andrewgpaul · Post by **andrewgpaul** » 2004-12-22 09:01pm

i wonder, though; if humans apparently originated* on Corellia, wouldn't Corellia's surface gravity, day length, orbital radius and peroid, etc, be the basis for any Galactic standards? Mind you, that makes it harder to calculate, since there aren't any films set there

*for sufficient values of 'originated'.

Hardy · Post by **Hardy** » 2004-12-22 09:13pm

andrewgpaul wrote:i wonder, though; if humans apparently originated* on Corellia, wouldn't Corellia's surface gravity, day length, orbital radius and peroid, etc, be the basis for any Galactic standards?

You should find throughout the EU that Coruscant is considered the ideal planet. It's also the standard for measurement in the Galaxy.

After all, it is the Capital.

Mind you, that makes it harder to calculate, since there aren't any films set there

"Impossible" is a better word.

phongn · Post by **phongn** » 2004-12-22 09:21pm

SWTC has some information on these things.

Hardy · Post by **Hardy** » 2004-12-22 09:43pm

phongn wrote:SWTC has some information on these things.

Read:

In the OP, I wrote:I am aware of([the Planets page is] my favorite page on SWTC) Dr. Saxton's derivations from role-playing guides, but canon estimates would seem far more valid.

phongn · Post by **phongn** » 2004-12-22 09:44pm

Whoops, sorry about that.

Robert Treder · Post by **Robert Treder** » 2004-12-23 04:07am

ItWoAotC lists distances for routes travelled in Kenobi and Skywalker's chase of Zam Wessel, including Anakin's free-fall. That could help determine Anakin's velocity.

Unfortunately, I'm at my parents' house for the holidays, and do not have my book with me.

Hardy · Post by **Hardy** » 2004-12-23 11:32am

Robert Treder wrote:ItWoAotC lists distances for routes travelled in Kenobi and Skywalker's chase of Zam Wessel, including Anakin's free-fall. That could help determine Anakin's velocity.

Cool. When I last saw AOTC, I timed Anakin's fall to 14 seconds. You can plug that into g=2d/t². If Anakin fell anywhere between 1300 and 1400 metres, then Saxton's derivations may be correct. If he fell anywhere between 950 metres and 1000 metres, then the default assumption is correct.

It's unfortunate that you don't have the book with you, however.

Grand Moff Tim · Post by **Grand Moff Tim** » 2004-12-23 05:04pm

Hardy wrote:
Robert Treder wrote:ItWoAotC lists distances for routes travelled in Kenobi and Skywalker's chase of Zam Wessel, including Anakin's free-fall. That could help determine Anakin's velocity.
Cool. When I last saw AOTC, I timed Anakin's fall to 14 seconds. You can plug that into g=2d/t². If Anakin fell anywhere between 1300 and 1400 metres, then Saxton's derivations may be correct. If he fell anywhere between 950 metres and 1000 metres, then the default assumption is correct.

It's unfortunate that you don't have the book with you, however.

I do. It says Obi-Wan freefalls 285m.

Hardy · Post by **Hardy** » 2004-12-23 05:25pm

Grand Moff Tim wrote: I do. It says Obi-Wan freefalls 285m.

Well, something's not right. If it really did take 32 seconds for Obi Wan to fall 285 metres, then we'd have a gravity of about 1/3 that of of the Moon. My measurement of the screen time it takes for him to fall is most likely the flawed value.

Falling 285m on Earth is a seven second fall, by the way.

Does it say anything about Anakin's fall?

Grand Moff Tim · Post by **Grand Moff Tim** » 2004-12-23 05:54pm

Hardy wrote: Well, something's not right. If it really did take 32 seconds for Obi Wan to fall 285 metres, then we'd have a gravity of about 1/3 that of of the Moon. My measurement of the screen time it takes for him to fall is most likely the flawed value.

Falling 285m on Earth is a seven second fall, by the way.

Does it say anything about Anakin's fall?

I'm afraid not.

andrewgpaul · Post by **andrewgpaul** » 2004-12-23 06:18pm

Hardy wrote:
andrewgpaul wrote:i wonder, though; if humans apparently originated* on Corellia, wouldn't Corellia's surface gravity, day length, orbital radius and peroid, etc, be the basis for any Galactic standards?
You should find throughout the EU that Coruscant is considered the ideal planet. It's also the standard for measurement in the Galaxy.

After all, it is the Capital.

Fair enough. My only thought was, if the humans were settled on Corellia with pre-spaceflight technology, all their units of measurements would be fefined based on Corellia, before they ever discovered Coruscant. A similar thing is mentioned in Asimov's Foundation; Earth is long since forgotten, yet the standard measurements are still seconds, days, years, etc based on Earth. One character even mentions looking for a planet whose characteristics match the standard units, and then you'd have found Earth. if the EU states that current SW units of measurement are based on Coruscant's physical properties, however, then I'm obviously in the wrong.

Hardy · Post by **Hardy** » 2004-12-23 06:43pm

andrewgpaul wrote:
Hardy wrote:
andrewgpaul wrote:i wonder, though; if humans apparently originated* on Corellia, wouldn't Corellia's surface gravity, day length, orbital radius and peroid, etc, be the basis for any Galactic standards?
You should find throughout the EU that Coruscant is considered the ideal planet. It's also the standard for measurement in the Galaxy.

After all, it is the Capital.
Fair enough. My only thought was, if the humans were settled on Corellia with pre-spaceflight technology, all their units of measurements would be defined based on Corellia, before they ever discovered Coruscant.

Your reasoning is not unjustified, but you may want to check out phongn's link to see why Coruscant is the standard for measurement.

President Sharky · Post by **President Sharky** » 2004-12-23 08:21pm

I can confirm that Obi-wan's free fall from the assassin droid to Anakin's speeder is 285 meters, and that Anakin's fall from his speeder to Zam's is described as "nearly 600 meters"

The Original Nex · Post by **The Original Nex** » 2004-12-23 08:59pm

President Sharky wrote:I can confirm that Obi-wan's free fall from the assassin droid to Anakin's speeder is 285 meters, and that Anakin's fall from his speeder to Zam's is described as "nearly 600 meters"

....which unfortunately, seems to be mathematically impossible....

Hardy · Post by **Hardy** » 2004-12-23 09:12pm

President Sharky wrote:I can confirm that Obi-wan's free fall from the assassin droid to Anakin's speeder is 285 meters, and that Anakin's fall from his speeder to Zam's is described as "nearly 600 meters"

Thanks.

<600 metres in 14 seconds or 6.1m/s² upper limit.
That's an 11 second fall on Earth and a 9.3 second fall based on RPG figures.

It might be a good idea to subtract the time it takes for Obi-Wan to say "I hate it when he does that" from the timing of Anakin's freefall, since it seems to interject with the documentation of the freefall. Assuming that the shot lasted two seconds, we can subtract that from the 14 second measurement and thus get 8.3m/s².

Using a combination of memoryand stopwatch, I seem to recall the Sentorial Ship's wings taking 0.5s to fall the >1.7m(judging by the height of the decoy, which should be similar to Natalie Portman's) that separates them from the ground. That's about 13.6m/s² lower limit. A measurement that doesn't rely on photographic memory is more accurate, though.

Hardy · Post by **Hardy** » 2004-12-23 09:19pm

The Original Nex wrote:
President Sharky wrote:I can confirm that Obi-wan's free fall from the assassin droid to Anakin's speeder is 285 meters, and that Anakin's fall from his speeder to Zam's is described as "nearly 600 meters"
....which unfortunately, seems to be mathematically impossible....

Unless the shots of Anakin jumping into a speeder and flying towards Obi-Wan happen to be concurrect with shots of Obi-Wan falling. The scene where Obi-Wan falls is not entirely homogenous. I did note many interjections in shots.

For a movie I've seen less than handful of times and haven't seen since August, I sure do recall a quite a bit