# Homework Help: Save The World

1. Jan 16, 2008

### winston2020

I'm currently in grade 12 physics. For my summative project in the class (which is worth a large part of my final mark) I have to think of three separate ways to divert a large asteroid away from hitting earth. We were each given a real object and stats on the object. My first problem is that I don't know what most of the stats mean

Here's a little chart:
Object a (AU) | e | i (deg) | w (deg) | node (deg) | m (deg) | q (AU) |
1981 Midas 1.78 |0.650| 39.8 | 267.7 | 357.0 | 114.0 | 0.621 |

Q (AU) | P (yr) | H (mag) | MOID (AU) | ref | class |
2.93 | 2.37 | 15.50 | 0.003330 | 62 | APO* |

a (AU): Semi-major axis of the orbit in AU
e: Eccentricity of the orbit
i (deg): Inclination of the orbit with repsect to the ecliptic plane and the equinox of J2000 (J2000-Ecliptic) in degrees
w(deg): Argument of the perihelion in degrees
node (deg): Longitude of the ascending node in degrees
M (deg): Mean anomoly at epoch in degrees
q (AU): Perihelion distance of the orbit in AU
Q (AU): Aphelion distance of the orbit in AU
P (yr): Orbital period in Julian years
H (mag): Absolute V-magnitude
MOID (AU): Minimum orbit intersection distance(the minimum distance between the osculating orbits of the NEO and the Earth)
ref: Orbital solution reference
class: Object classification (APO="Apollo" * indicates possible threat)
(AU): Astronomical Unit: 1.0 AU is about 1.5x10^8 km

If you guys could decipher some of these for me it'd be greatly appreciated :D

2. Jan 16, 2008

### blochwave

en.wikipedia.org

no joke, I believe it'll have nearly every term on there, semi-major axis, eccentricity, etc.

The first two are geometric terms that define the ellipse that its orbit traces, the ecliptic plane is the plane the planets (more or less)are on, the perihelion you can look up, etc.

3. Jan 16, 2008

### winston2020

OK, thanks I've looked through those. Here's another question: Do all objects in the solar system orbit in the same direction? (i.e. An asteroid will orbit the sun clockwise, all the planets and other asteroids will also orbit clockwise)

Is that correct?

4. Jan 16, 2008

### blochwave

It's not guaranteed fact, but all the planets do. All this stuff used to be a big spinning disk that slowly coalesced into the planets, so everything part of that original pile of dust will be orbiting the same way, as the planets and asteroids in the belt do. Also in the same plane, the ecliptic plane

If an asteroid was wandering through the galaxy and got pulled in by our solar system's gravity, it might not be orbiting at all in the same plane or direction, just depending on how it approached

5. Jan 16, 2008

### winston2020

Ok, thanks :D