Notation used for distance Earth-Moon and Moon diameter

Started by Marcos Silveira, November 24, 2007, 02:35:18 PM

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Marcos Silveira

Does anyone here know the distance earth-moon and the moon diameter in the notation (ex: 1e+006) used in TG2?? ???

dhavalmistry

#1
1e+006 = 1000000 m

the number after "+" equals that many zeros

6.378e+006 = 6378000 m

In this case you multiply the number (6.378) by the number of zeros (1000000)
"His blood-terragen level is 99.99%...he is definitely drunk on Terragen!"

child@play

#2
earth-moon distance is about 380.000 km i think


edit: oh, misread the question, nevermind ^^
perfection is not when there's nothing more to add, it's reached when nothing more can be left out


Oshyan

TG2 uses standard scientific notation to more easily handle the wide range of scales used in creating scenes from planets to pebbles.

The distance to the moon varies a bit I think, but the average is 384,403km according to Wikipedia. Here's a scientific notation calculator to help you in future conversions: http://www.webmath.com/sn_convert.html

The result is 3.84403 × 105, or in TG2 terms 3.84403 + 005

- Oshyan

jo

Hi,

I think it would be better to not use scientific notation though. Hopefully in the future we can improve the formatting of things, including specification of units, so it isn't needed. I know what scientific notation is and everything, but I always have to stop and think about it a bit. It is not a very user friendly way to do things at all, except to certain users who are very numerically minded :-).

Regards,

Jo

Sethren

I tend to agree. These 3.84403 + 005... numerical terms are headaches.    ;D

Oshyan

I suppose that's true Jo. There is theoretical advantage in it when dealing with very large numbers (e.g. so large that they don't fit in the confines of a normal sized input box), but in practice the notation in TG2 is often as long as the large numbers and that would only be overcome when dealing with truly gargantuan scales (e.g. simulating a full solar system at 1:1 scale).

- Oshyan

Matt

You can also enter numbers without the scientific notation, as long as you remember that values are in metres. Entering 384403000 is perfectly fine, although you will find it has been formatted differently the next time you open that window.

Oshyan, I think you are 3 orders of magnitude out, as you didn't convert from km to metres.

Matt
Just because milk is white doesn't mean that clouds are made of milk.

Marcos Silveira

Quote from: Matt on November 26, 2007, 12:54:28 PM
You can also enter numbers without the scientific notation, as long as you remember that values are in metres. Entering 384403000 is perfectly fine, although you will find it has been formatted differently the next time you open that window.

Oshyan, I think you are 3 orders of magnitude out, as you didn't convert from km to metres.

Matt


Oh man, it's madness...
I put the values but the planet jumped "out of bounds", it got so distant that didn't match the real moon distance in the sky...
When I put the value: 384403 it was still distant but when I entered the value above "it went neighbor Uranus" :o
Is this correct??
Earth-moon Distance: 384,403,000 meters = 3.84403e+008????
Moon radius: 1,737 meters = 1.7e+003????

jo

Hi Ronin,

Wouldn't it be nicer if you could just enter "380000 km" :-).

Regards,

Jo



Harvey Birdman

#10
Ro-nin - your problem isn't the distance from earth to moon, it's the radius of the moon. The moon is approximately 1,740 km (1.737 E + 6 m) in radius, not 1,740 meters.

(Don't feel too bad. A similar error at NASA a few years back resulted in the destruction of a Mars probe, IIRC.)

Oshyan

Quote from: Matt on November 26, 2007, 12:54:28 PM
You can also enter numbers without the scientific notation, as long as you remember that values are in metres. Entering 384403000 is perfectly fine, although you will find it has been formatted differently the next time you open that window.

Oshyan, I think you are 3 orders of magnitude out, as you didn't convert from km to metres.

Matt

:o This stuff *is* confusing. ;)

- Oshyan

Jugalator

One mode that my calculator had, which I found pretty useful for my poor brain to work with, was that it could be set to only work in e-6, e-3, e3, e6, e9, and so on. That is, instead of formatting numbers to be "1.239e5", it said "123.9e3". The advantage of that was that "e3" is kilo/thousands, "e6" is Mega/millions, and so on. Just like you're often more used to work with a specific numeric system of base 10, I think you're also usually more used to work with these prefixes.