ISS it on Wikipedia?


Ok, I'm not trying to convince you that I was a snake in my previous life. ("In the former life, I was the asp, and you were Cleopatra...." - very complimentary isn't it?)

Yes, it is on Wikipedia. Even in kilograms. It made me very happy. I mean, I know that someone probably knows the mass of the International Space Station - after all, you kind of have to know those kinds of things in order to put it into and keep it in orbit - but I just didn't figure I would get to be one of those privileged people. Yes, Wikipedia puts the mass of the ISS at 227,267 kg. This made me happy until I figured out that I didn't really need the mass of the ISS. It would actually have been a lot more helpful to me if it had given the radius of the ISS's orbit. Then I was sad because Wikipedia did not give me its orbital radius. But, it did give me its average altitude, so I just added that to the average radius of the earth. Then, armed with all my centripetal force and force due to gravity equations, I set out to find the speed at which the ISS travels around the earth. Using all these weird, sort-of-random numbers like the universal gravitational constant and the earth's mass (not so weird or random), I solved my equation and found the speed of the ISS to be 7.70*10^3 meters/second. Unfortunately, meters/second don't mean much to me, and there was no way to check my answer since everything on the Internet gives the ISS speed in miles per hour. But then I found a conversion thingy and converted my answer to 17,224 miles per hour, which is pretty close to the Wikipedia answer of 17,210 miles per hour. Yippee! That makes me very happy. Then using the speed and the distance traveled in one orbit (the orbital circumference), I was able to find how long it took to make one orbit, its orbital period: 5.49*10^3 seconds or 91.5 minutes. That's close to the Wikipedia answer: 91.34 minutes. Since orbital frequency is inversely related (I hope I got that right, basically orbital period=1/frequency) to orbital period, I found out how many times per day the ISS orbits the earth which turned out to be 15.77 times per day, close to Wikipedia's 15.72397664 times per day. Then, I figured that I might as well compute the gravitational force exerted on the ISS which I found to be 2.00*10^6 Newtons which is around 90% of the gravitational force that would be exerted on the ISS at sea level.

So anyway, after that big long paragraph on gravitational force and such stuff, I bet you can guess which chapter in physics I just finished. Yep, uniform circular motion and gravity, and it is my very favorite chapter so far (and so for the test, I promptly missed some stupid stuff; man, there goes my physics grade).

As for the accuracy of all my answers, I figured I was relatively close, especially since I probably worked with a lot of imprecise numbers. So, with all the significant figures and adding the average ISS altitude to the average radius of the earth, I was pretty close. And sorry about all the scientific notation; you get so used to doing it for all the physics problems that you don't really think anything of it.

So, what was that big, long rant for? Well, who knows. I guess I was just excited that I could actually figure some of these things out, especially the ISS because it's a little more real to me than some random satellite orbiting at a random speed or altitude.

So, you'd think maybe there's a chance you might be able to see the ISS as it passes over you. Well, it turns out that you can-very easily, actually. If you go to this website, you can select your state and city, and it will tell you the next time you can see the ISS, which is for us, Thursday.

ISS sightings are actually pretty regular except for the fact that they seem to skip a week here and there. This is because of the conditions that have to exist for you to see the ISS. Basically, the ISS has to be in the sun, and you have to be in the shade. Or, it has to be dark, but not too far before sunrise or after sunset. So, you combine that fact with the frequency of the ISS orbit, and you get some varying times for sightings.

If you go to look for the ISS, it shouldn't be too hard to find. The approach and departure figures on the ISS sightings page basically just tell you where the ISS will appear and where it will disappear. (Divide the dome of the sky roughly into degrees-you know, 90 degrees is straight up, 45 degrees is halfway down from that, and so on-and that should give you a general idea of where to look.) Then all you do is look for a bright, moving star. It's as simple as that.

Ok, I think this qualifies as a long, boring post, and there wasn't even any poetry or even a story or anything! (Come on guys, don't act so relieved!) So, here are some videos that I thought were pretty cool.

The sound's pretty cool on this one.

It's neat how you can see the line on the water under the plane as he goes through his passes in the next video.

And last but not least, a video and sound of a plane going supersonic. Crank up the sound, guys, and revel in the resounding BOOM!

Ok, that's the end of this endless post, and I feel like I just wrote a lab report.

Happy Birthday!!!


I just happened to remember that Steve's birthday was yesterday, or today, or tomorrow. Unfortunately, I can't remember which. So here is a special birthday wish for him. I hope he understands it better than me.

Now that's one cool birthday cake! Or maybe it's a card...

Perhaps Ben should consider getting him a present. Here's an idea, Ben. Maybe in Vegas you could find one with fake jewels all over it.