Here is something to boggle your mind. You think your argument is strong with Sun containing 98% of the Solar system's total mass? It is actually something like 99.8%!! to think that stray jupiter-size brown dwarves can weigh anywhere near the total stellar masses that we see betrays complete lack of understanding of the difference of scales involved.

you are assuming that by "metal" they mean iron etc. all the examples that you cite (except H and He) are "metals" by astrophysicists' definition.

er, I think they meant $1000 per car, not per car per year! why would you ask for $1000 per year? it's not as if speeding fines are worth that much on average per car per year.

yeah, just an engineering problem. you might also want to think about a way to move at 0.9c and yet dodge all the stuff that will hit you like a hydrogen bomb...

That's not science. just statistics. What it suggests is that the subway riders in your city come from the same population as the one that CDC report is about. (and that you did a pretty good job of sampling without possible biasing factors! :) )

No, I don't think her is denying the existence of orbit degradation. The problematic part is you saying that it happens "due to gravity". gravity keeps it in orbit, lack of vacuum is what brings it down. Rahul

Mars's orbit isn't a function of its mass. It only depends on Sun's mass. you could, however, make the same point using Phobos/Diemos's orbit.

I think "Qaher" actually means something like "wrath" rather than "dominant". That is true at least in Urdu, which has a lot of influence of persian language. Can someone who knows persian confirm?

er... 10000 km is "somewhat over a quarter of the way to the moon"? if you really think that the moon is only about 4 earth diameters away from the earth, your mental model of solar system needs a serious recalibration! :)

I was also a part of a similar study. We measured the breast size of kids from grades 3rd to 10th. While there was absolutely no gender-based difference in kids of 3rd grade, by the time they reached grade 10, the difference was clearly statistically significant. The young cohort pretty much proved that there is very little gender bias in breast sizes! "

You do realize that your nice old lady can't also drive a car without killing many people or herself in the process? Yet all of us seem to be doing fine with a culture dependent on driving cars. It appears that having a license test for use of these high speed trains would be simple enough, no?

Actually, it is about 11000 light years away. The 300-odd years mentioned is actually the time when the supernova was observed on earth. A young neutron star just 300 light years away from earth would have been impossible to observe (since the supernova creating it would've wiped out any future observers. :) )

being concerned about a cycle has nothing to do with the total life of the thing. That is like saying "Earth is >4 billion years old and we are concerned about the fact that the sun didn't rise for 2 days?"

hmmm... the problem is that for doing this you will also have to carry the whole asteroid with you. so, even though the thrust that will be provided by the ground asteroid should be enormous in totality, the acceleration it will provide will be mitigated to a large extent due to the necessity of accelerating the rest of the asteroid.

Then again, that is a problem with any rocket propellant/fuel... you take a lot of fuel and then propel it away, giving you some acceleration... you know what, never mind... that was a little stupid of me... the fact that you threw away the whole asteroid at the end, means that you gained that much momentum for yourself, regardless of how fast you threw the powdered substance away. I'll still post this, just in case someone else who, like me, has forgotten all physics might start wondering the same thing.

I wonder though, how much nuclear fuel would one have to carry to generate that much thrust? because, essentially the asteroid only gives you enormous amount of propellant to use, not fuel... to carry the amount of nuclear fuel that can propel essentially the whole asteroid away can't be a trivial problem!