Search found 17398 matches
- Fri Aug 31, 2007 4:04 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: Lunar Eclipse (APOD 30 August 2007)
- Replies: 19
- Views: 7326
But, actually, how strong is the brightness? I'd like to know that if there is observed data. I made a few measurements off the images I took during the eclipse, and it appears that the surface brightness of the Moon was about 1000 times reduced at mid-eclipse. Your rendering is very attractive, bu...
- Thu Aug 30, 2007 6:04 am
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: Could Hydrogen Peroxide Life Survive on Mars? (28 Aug 2007)
- Replies: 14
- Views: 4465
Re: There is no hydrogen peroxide on Mars
The bottom line is that with these incompatible chemicals in the soil, it is physically impossible for any significant amount of hydrogen peroxide to exist on Mars. Doesn't somebody at NASA know a little basic chemistry? By perpetuating this peroxide myth, they really, really look like fools. The t...
- Tue Aug 28, 2007 6:26 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: Discussion of APOD 15 August 2007: Mysterious Streaks
- Replies: 97
- Views: 78079
One would think the lines would show up dark against the sky light if there were power lines there. In my mind the streaks could be bits of a broken up comet fragment traveling together, and briefly illuminating as they burn up in the atmosphere. I think the 36 minute spread from the first to the l...
- Mon Aug 27, 2007 4:51 am
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: No eclipse? (APOD 26 August 2007)
- Replies: 7
- Views: 2864
Re: Question about the diagram linked from the APOD page
I wondered if the chart linked from the APOD page might be for a solar eclipse. Since the size of the shadow cast by earth's umbra is greater than the size of the moon then it would cover the entire surface area of the moon. How would it be possible for it to obscure varying degrees of lunar visibi...
- Fri Aug 24, 2007 4:17 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: Southern Moonscape, lunar craters (APOD 23 Aug 2007)
- Replies: 36
- Views: 11125
Re: crater upon crater
Why are there so many craters on the moon and how often do they hit? We don't see as many on other planets do we? About 4 billion years ago, something happened that flung a lot of material into the inner Solar System. This was the Late Heavy Bombardment, which isn't well understood, but may be rela...
- Thu Aug 23, 2007 11:10 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: Discussion of APOD 15 August 2007: Mysterious Streaks
- Replies: 97
- Views: 78079
Actually gregg07 if you check Iridium flare fits better. Nope, there were no flares, nor even more than one Iridium satellite in the field at the times the images were made. Also, there's nothing to suggest that the light on the hill is a spotlight aimed at the sky. And it's no less likely to have ...
- Wed Aug 22, 2007 7:32 pm
- Forum: The Asterisk Café: Discuss Anything Astronomy Related
- Topic: What Happens If Our Sun Dies..
- Replies: 14
- Views: 6945
I thought space was darn cold. :lol: Space in the Solar System is pretty bloody hot. In Earth orbit, say where you find the ISS, the temperature is around 1000K. between the planets, it can reach nearly 1 million K. Of course, the particle density is so low that you transfer almost no energy convec...
- Tue Aug 21, 2007 2:27 am
- Forum: The Asterisk Café: Discuss Anything Astronomy Related
- Topic: What Happens If Our Sun Dies..
- Replies: 14
- Views: 6945
Well i dont think earth might survive if the sun will become a white drawf soon.. It is possible for the Earth as a planet to survive the process of our Sun becoming a white dwarf. A red giant is tenuous and cool enough that a planet might continue to orbit inside it. However, the Sun will also hav...
- Mon Aug 20, 2007 7:42 pm
- Forum: The Asterisk Café: Discuss Anything Astronomy Related
- Topic: What Happens If Our Sun Dies..
- Replies: 14
- Views: 6945
Re: What Happens If Our Sun Dies..
But what happens,if our sun dies n become a neutron star..? Will all the gravity be lost? Will all the planets,collapsed n become unarranged? Will we collide with other planets..? Will our planet,be dark forever..? Our sun is not massive enough to become a neutron star. It will eventually become a ...
- Mon Aug 20, 2007 4:50 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: Discussion of APOD 15 August 2007: Mysterious Streaks
- Replies: 97
- Views: 78079
- Sun Aug 19, 2007 11:47 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: Discussion of APOD 15 August 2007: Mysterious Streaks
- Replies: 97
- Views: 78079
Re: Streaks In Orion
IRIDIUM 8 (#24792) 00:40:38h UT (Lowest streak. Slight flare) IRIDIUM 51 (#25262) 00:49:55h UT (Flare) IRIDIUM 7 (#24793) 00:56:05h UT (Small duration flare) IRIDIUM 6 (#24794) 01:06:56h UT (Faint trail) IRIDIUM 5 (#24795) 01:08:21h UT (Top most very faint trail) Unfortunately, these times are not ...
- Fri Aug 17, 2007 4:04 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: Discussion of APOD 15 August 2007: Mysterious Streaks
- Replies: 97
- Views: 78079
Re: Horizontal Streaks
If you look closely you will notice there are more than 5 streaks in the image... they begin near the base of the photo and track toward the upper-left corner... at the point where the three brightest streaks are located they shift direction and begin tracking toward the upper-right corner of the i...
- Fri Aug 17, 2007 1:03 am
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: Discussion of APOD 15 August 2007: Mysterious Streaks
- Replies: 97
- Views: 78079
- Fri Aug 17, 2007 12:59 am
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: Discussion of APOD 15 August 2007: Mysterious Streaks
- Replies: 97
- Views: 78079
Re: Calsky
1) Check location. I searched: Turkey, than Beynam.. it gives me: Beynam, Turkey WGS84: Lon: +32d53m45.0s Lat: +39d41m21.0s Alt: 1324m 2) Check date and time: Date 12. 8. 2007, time - the best is maybe UTC, so than you must enter 0:15 for beginning and 1 hour span (to 1:15 UTC).. I think you've mad...
- Thu Aug 16, 2007 8:30 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: Discussion of APOD 15 August 2007: Mysterious Streaks
- Replies: 97
- Views: 78079
Re: About the composite image
I submit: Location Beynam near Ankara, Time: 4:00 - 7:00 local time. and I receive this in Calsky.com: 4:23:26 Iridium 35, -1,9 mag (in Orion) 4:32:45 Iridium 97, -4,7 mag (in Orion, spare satellite, time and mag can be inaccurate) 4:42:04 Iridium 5, -2,6 mag (in Orion) 4:51:19 Iridium 6, +1,2 mag ...
- Thu Aug 16, 2007 1:53 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: Discussion of APOD 15 August 2007: Mysterious Streaks
- Replies: 97
- Views: 78079
reminds me of this discussion. http://asterisk.apod.com/viewtopic.php?t=249 Yeah, me too. Just like in that case, we've got one or two simple, straightforward possibilities, and a discussion that takes on a life of its own as people try to come up with off-the-wall, crazy theories- many based on a ...
- Wed Aug 15, 2007 11:03 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: Discussion of APOD 15 August 2007: Mysterious Streaks
- Replies: 97
- Views: 78079
Re: Please, somebody explain me.
Both the stars and the trees have pretty well defined positions in this photograph, which I think is incompatible with the fact that Earth rotates about 10 degrees around its axis in the term of 40 minutes. The trees look well defined, then the camera was rotating with Earth and the stars should ha...
- Wed Aug 15, 2007 4:42 am
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: Discussion of APOD 15 August 2007: Mysterious Streaks
- Replies: 97
- Views: 78079
Where Chris comes up with the idea of stacking is news to me, and not listed about the image. The same image was submitted to Spaceweather.com with the following comment: I took a 100-picture series of 105-second wide angle pictures using a Canon EOS 300D camera at ISO1600 and a 10-22 mm lens at 10...
- Tue Aug 14, 2007 8:13 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: LASER beam (APOD 31 July 2007)
- Replies: 21
- Views: 7999
I'm curious how astronomers go about detecting naturally-occurring stellar lasers. Are they detecting the coherence of the laser light, or simply the strong peak emission frequency in the stellar spectrum? As noted earlier, laser light loses its coherence quickly with distance, so that cannot be us...
- Tue Aug 14, 2007 7:33 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: Discussion of APOD 15 August 2007: Mysterious Streaks
- Replies: 97
- Views: 78079
Re: Discussion of APOD 2007 August 15: Mysterious Streaks
What are they? Thoughts? Normally, when you see short streaks through Orion they are geosynchronous satellites. But in this case, the direction of travel is too far off the ecliptic, and the angular speed is too great (assuming each streak was caught in a single 105-second exposure). Supposedly, th...
- Tue Aug 14, 2007 1:25 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: LASER beam (APOD 31 July 2007)
- Replies: 21
- Views: 7999
Re: APOD - laser strike at galactic centre
Wrong wrong wrong Coherence is whenphotons are "in step" and have a definite phase relation. Unrelated to the point you are making. The question I was addressing suggested that the coherence of a laser could be used as a signature of an artificial source. I merely pointed out that coheren...
- Thu Aug 02, 2007 4:13 am
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: Cratering on Dione question (APOD 01 August 2007)
- Replies: 24
- Views: 7145
Re: Cratered from behind
Seems to me that the more heavily cratered side of Dione should be the trailing side.Right? Dione has about an equal chance of hitting a prograde bit of debris on the leading or trailing edge. But there's bound to be lots of retrograde debris as well, which will selectively hit the leading edge. Al...
- Thu Aug 02, 2007 4:06 am
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: Cratering on Dione question (APOD 01 August 2007)
- Replies: 24
- Views: 7145
- Thu Aug 02, 2007 12:57 am
- Forum: The Asterisk Café: Discuss Anything Astronomy Related
- Topic: Hello and a Question
- Replies: 3
- Views: 3328
Re: Hello and a Question
Q: I have observed, during my several months here, that the moon does not rise from a predictable spot on the horizon each night. In an urban setting you can't see this, but here I have a clear view of the horizon. One night it rises directly across the lake between two, large, oak trees and the ne...
- Wed Aug 01, 2007 10:49 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: LASER beam (APOD 31 July 2007)
- Replies: 21
- Views: 7999
Re: APOD - laser strike at galactic centre
Ref. todays picture and comment regarding the effect of shining a laser at the galactic centre. Forgetting for the moment the distances and hence time frames involved and given that we, with our limited technology, are able to detect water molecules in distant atmospheres, is it not the case that n...