3,601 reputation
1117
bio website about.sjrdesign.net
location Boulder, CO
age 31
visits member for 2 years, 8 months
seen Jun 29 at 7:04

Professional geophysicst/astronomer who also writes the blog, "Exposing PseudoAstronomy," and runs the podcast by that name.


Nov
30
answered What are the facts that allow accepting the Oort cloud theory?
Nov
26
comment November 25th 2011 partial solar eclipse visibility from Christchurch, New Zealand
So, did you see anything? I think that's the real question at this point. :)
Nov
25
comment November 25th 2011 partial solar eclipse visibility from Christchurch, New Zealand
Alright, answer is corrected. I also had your longitude as W instead of E. That's why Starry Night did +11 instead of +13.
Nov
25
answered November 25th 2011 partial solar eclipse visibility from Christchurch, New Zealand
Nov
21
comment Liquid Water in “mid-ice” on Europa. Mechanism?
Updated since I got the paper.
Nov
20
comment Liquid Water in “mid-ice” on Europa. Mechanism?
His response was "tomorrow." Guess he doesn't want to VPN in.
Nov
20
answered Liquid Water in “mid-ice” on Europa. Mechanism?
Nov
17
comment Does anybody actually do astrometry in the 21st century?
Geoff, I'm adding a comment instead of answer because this isn't a full answer, but I'm pretty sure the answer is "yes." You may periodically hear about leap seconds being added or taken out of years at midnight on New Year's, and I'm pretty sure those come from astrometry measurements on the March equinoxes.
Nov
16
comment Best time of the year to see the star Alpha Centauri in Chile, Santiago
I need to not write answers here when I'm about to go to bed. Corrected.
Nov
16
answered Best time of the year to see the star Alpha Centauri in Chile, Santiago
Nov
12
comment How does the central peak in moon craters form?
Hmm. That's not really a good model for the cratering process - at least not into rock. I could see that applying to ice, like on Enceladus or Europa. It's the effective explosion/vaporization of the projectile that creates the crater in the first place. Now, the splash-up in that movie is reasonable, sorta, though probably much higher than would happen in normal rock.
Nov
11
comment How to concisely explain apparent retrograde motions of planets?
To add, the way I normally (when I remember) remember prograde and retrograde is that the sun, over the course of many days relative to the stars, appears to move west to east. Going with the sun (the planets when prograde) is what ancient cultures who worshiped the sun would probably think of as "good" -> "pro." When it goes the opposite direction of the sun - relative to the stars over many days), that's against normal motion -> "retro."
Nov
11
answered Use of advanced mathematics in astronomy, like topology, abstract algebra, or others
Nov
11
comment How to concisely explain apparent retrograde motions of planets?
Yeah, got my terms mixed up, I wrote that when I was watching the clock to run for the bus. But, I disagree with your point that I got my overall motions wrong -- it's just how I think of the motion. I always think about it relative to the stars, so I just didn't clarify (which I now have) about the diurnal motion.
Nov
10
answered How to concisely explain apparent retrograde motions of planets?
Nov
10
comment How does the central peak in moon craters form?
This is not actually going to form a central peak in any way. You'll form a crater, and it's neat, and I actually recommend doing this in a clear tub (like disposable containers you get in a 5-pack at the grocery for $3) and use layers of different-colored things like flour, oreo crumbs, graham cracker crumbs, etc. But you will not get a central peak, and it's not a great analog because the marble will not be destroyed in the impact, which you need to do this.
Nov
9
answered Where does the dust on the moon come from?
Nov
3
comment 2012: Is there some astronomical event happening?
Can't edit my comment, so I'll just add -- people on this site will usually vote down a question/statement on pseudoscience topics, so that was probably why it was downvoted. I've actually only downvoted one person's post before, I think because it was completely illegible.
Nov
3
accepted What's the most accepted theory for Blue Stragglers These Days?
Nov
3
comment 2012: Is there some astronomical event happening?
I didn't down-vote your question.