Lois & Clark Forums Forums Fan Fiction Fanfic Related Questions about the Nightfall Asteroid

Well...according to this site:

http://www.exploratorium.edu/ronh/weight/

One hundred pounds on earth equals 6.7 pounds on Pluto. Pluto is something like 1300 miles in diameter. My guess is that whatever gravity there is on nightfall would be barely noticable.

Escape velocity would involve a human sized jump, I suppose....

Right. Clark would have to cling to the rock not to float away. In science fiction over the years there has been much discussion of mining the asteroid belt. Even the biggest asteroids would have very little gravity.

Artemis

For calculating nightfall's mass and gravity... you need more data. 17 miles across tells you nothing. You need the density to calculate it's gravity. For all we know it could be 17 miles long, 1 inch wide and the density of styrofoam! However, that calculator I linked previously has preset densities for ice, porous rock, dense rock and iron.

The NEAR-Shoemaker probe landed on the asteroid Eros in 2001. It hit at about 3-4mph and they were afraid it would bounce back into space I believe. The second article list's Eros' escape velocity as 22mph.

http://en.wikipedia.org/wiki/NEAR_Shoemaker
http://science.howstuffworks.com/asteroid3.htm

I've also seen shows on Mars' moons talking about how a an olympic jumper could probably achieve escape velocity. Mars' moons are thought to be captured asteroids.

http://en.wikipedia.org/wiki/Moons_of_Mars
Wiki lists the moon Deimos' escape velocity as roughly 11mph.

http://en.wikipedia.org/wiki/Deimos_[moon]
Link won't post, replace [] with ()

Wow! Thanks again everyone. I put out a question and I get back loads of feedback with plenty of information for further thoughts and fic improvement!

Just wanted to let everyone know how much I've appreciated your comments and leads. We've got some smart people here on the boards.

Coming late to the party here, but I'm with Bob on not letting the science bog down your story. After all, your main character is, I assume, a man who can *fly* because his molecular structure is *more* dense than ours. That very premise tells me that his universe doesn't operate on the same physics as ours.

Not really relevant to Doomsday, but the escape velocity thing can be a bit misleading for objects in orbit - in the case of Mars' moons, for example, you can jump fast enough to achieve escape velocity, but that just puts you into a slightly different orbit which will converge back with the orbit of the moon you left a few hours later.

Incidentally, I was trying to think of an easy way to explain just how massive an asteroid is, for the SF RPG I'm currently writing - I thought comparison with Mount Everest would be a starting point, until I worked out that Ceres, the largest asteroid, is several BILLION mount Everests, which puts things right back at the "too big to be really comprehensible" level. Nightfall looks to be ten or twenty Everests in mass, but of course a lot depends on what it's made of.

And as if by magic, the Astronomical Picture of the Day is Barringer Meteor Crater

http://antwrp.gsfc.nasa.gov/apod/ap090811.html

Good picture. I've been to Meteor Crater and it is very impressive in reality. The meteorites found were 92% iron, which makes them very dense. Hence a very large hole. The crater is near the Petrified Forest, which consists of horizontal trees whose cells were replaced by minerals, making the trees rock. It's a great area to visit, near Flagstaff, Az.

Artemis

Coming in late here but this might be relevant: NASA Can\'t Keep Up With Killer Asteroids

Nan

Wow! Quite an appropriate post, Nan. Congress mandates NASA to keep an eye out for cosmic objects that might hit the Earth, but gives them no money for telescopes to do the job. Typical government.

If something like Nightfall does happen in our universe, we're screwed.

I'm a member of the Planetary Society and they've marshaled the strength of the amateur astronomers around the globe to do their asteroid hunting. They offer the Gene Shoemaker NEO Grant program, a yearly award for the most significant find.
Also, recently NASA reduced the threat level of the Apophis asteroid (which is 680m across BTW). Apophis Asteroid
So thank you all for the good input. (Deep breath), so I'm about to attempt to try the Nightfall Asteroid issue in "Nighttime in the Daytime", posting soon. Right now my head hurts.

Artemis