724 reputation
312
bio website keith-s-thompson.github.com
location San Diego, CA
age 55
visits member for 1 year, 2 months
seen 37 mins ago

I'm a programmer and all-around nerd living in San Diego, California.
I work at JetHead Development Inc.

E-mail: Keith.S.Thompson@gmail.com


1h
comment Planets and Pluto? Neptune?
The cultural definition of "planet" has changed before. If you want to keep the number of planets at 9, how do you justify saying Pluto is a planet and Eris isn't? If a dozen Kuiper Belt objects had been discovered in the 1930s, we probably wouldn't be having this debate (though we might well be having a different one).
1d
comment can we see all binary stars as pairs?
According to Wikipedia, pairs of stars that appear close together in the sky but are not gravitationally bound are called "optical doubles". The two stars might be many light-years from each other but happen, by coincidence, to be on nearly the same line of sight as seen from Earth.
Nov
10
revised How is the universe bordered?
Spelling, grammar
Nov
10
suggested suggested edit on How is the universe bordered?
Oct
31
comment Could we fly/drive through Jupiter?
@Scottie: Yes, given technology sufficiently advanced to fly through Jupiter, we could fly through Jupiter. (Borrowing from science fiction, the Enterprise couldn't do it.)
Oct
31
revised Could we fly/drive through Jupiter?
Spelling, grammar
Oct
30
suggested suggested edit on Could we fly/drive through Jupiter?
Oct
29
comment Could we fly/drive through Jupiter?
In 2003, the Galileo probe was deliberately crashed into Jupiter's atmosphere. As expected, it did not survive.
Oct
28
comment How can we tell if the asteroid 2013 TV135 will hit Earth in 2032?
According to Wikipedia, it was removed from the JPL Sentry Risk Table on November 8, 2013. The latest estimate is that it will miss Earth by 0.76 AU (114 million km). Incidentally its estimated diameter is 450 meters, so the illustration is highly exaggerated.
Oct
28
awarded  Enlightened
Oct
28
awarded  Nice Answer
Oct
28
comment What will happen to our solar system if the milky way collided with Andromeda galaxy, would any planets survive?
A collision of the Milky Way and Andromeda galaxies would have very little direct effect on the Solar System. Why do you think otherwise? Or are you referring to the fact that the Sun will have expanded by then? If so, you need to be clearer.
Oct
27
comment What is the current accepted theory as to why Titan has retained its atmosphere?
I fail to see how that makes sense. I don't believe water is relevant. Venus doesn't have much water, but it retains a very think atmosphere. Titan has water, but it's cold enough that it's essentially a mineral. And the greenhouse effect doesn't "block the atmosphere"; it blocks outward infrared radiation, thus making the atmosphere hotter. I'd think that Venus loses more of its atmosphere to space than it would if it were colder.
Oct
24
answered What is the ratio of “real” stars in the sky?
Oct
23
comment How do we know that the speed of the influence of gravity is instant?
If I understand this correctly, we appear to experience a gravitational force directed at the point where the Sun is now, not where it was 8 minutes ago (the latter is where we see it). But if the Sun's core suddenly collapsed, and we were able to detect the resulting gravitational waves, we'd detect them 8 minutes after the event, and from a direction matching the visible position of the Sun, not from the direction of the apparent gravitational force. Is that correct?
Oct
23
comment Do extraterrestrial landscapes or planets count as nature?
Why would it not count as nature?
Oct
22
comment What will happen to life on Earth when Andromeda and Milky Way galaxies collide?
I'm hoping we'll move Earth to a safe distance by that time, for sentimental reasons if nothing else.
Oct
22
comment What would be the dynamics of a double-planet system, similar to Earth / Moon, but with both bodies nearly Earth-sized?
"Constellation" isn't the right word for this. A constellation is an apparent grouping of stars in the sky, or a region of the sky. I think replacing "constellation" by "system" would make your answer clearer. (For example, we already refer to the Earth-Moon system or the Jupiter system; the latter includes Jupiter and its moons.)
Oct
21
comment How did the Mars satellites “take cover” from the recent comet flyby?
MAVEN, for example, orbits Mars every 4.5 hours. It can't just move behind Mars and stay there for a while. What it can do is slightly adjust its own orbit in advance so that, when the comet is at closest approach, its orbital motion carries it behind Mars. It's velocity would only need to be changed slightly, and it would still be on the side of Mars facing the comet 2.25 hours before and 2.25 hours after the closest approach. (I'm assuming this is how it was done.) I'm sure you know this, but I don't think it's 100% clear from your answer.
Oct
6
comment What scientific evidence is there to support or refute the Iron Sun Hypothesis?
I think the article is consistent with what I wrote. "At 3 billion degrees, the core can fuse silicon nuclei into iron and the entire core supply is used up in one day." So silicon-to-iron fusion produces energy, but only lasts about a day; once the silicon is depleted, the iron can't be fused any further without consuming energy. (The jump from Si, atomic number 14, to Fe, atomic number 26, does seem odd; I clearly don't entirely understand this stuff.) Elements lighter than iron can be fuel for fusion reactions; iron and heavier elements cannot.