Search found 77 matches
- Sat Jan 19, 2013 7:16 pm
- Forum: The Library: Information Desk and Educational Resources
- Topic: What was the absolute magnitude of Eta Carinae in 1843?
- Replies: 4
- Views: 5444
Re: What was the absolute magnitude of Eta Carinae in 1843?
I actually work out a BV absolute magnitude of -16.8 for Eta Carinae's 1843 outburst. This weighs in at around ten million solar. This compares quite well with some supernovae.
- Mon Jul 18, 2011 5:18 am
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: APOD: A Busy Space Walk at the Space Station (2011 Jul 18)
- Replies: 63
- Views: 23994
Re: APOD: A Busy Space Walk at the Space Station (2011 Jul 1
I also see 4x Canadian and 1x Japanese. I was expecting something like 1,322 American and possibly half a Canadian if the Americans haven't covered it up with their own. Those people like flags. A lot.
- Fri Jul 01, 2011 9:04 pm
- Forum: The Science Labs: Participate in Citizen Science or Smartphone Science
- Topic: Help identify unusual circular cloud type over Italy
- Replies: 16
- Views: 11860
Re: Help identify unusual circular cloud type over Italy
It appears to be a slightly distorted contrail from a plane in circular holding pattern. It's much larger than naturally formed annular clouds and the kicker is that it's far beyond the foreground mountain, but below the cloud deck, and so is quite low but also very large, just what you'd expect fro...
- Sun Dec 12, 2010 4:04 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: APOD: Intrepid Crater on Mars (2010 Dec 08)
- Replies: 17
- Views: 4368
Re: APOD: Intrepid Crater on Mars (2010 Dec 08)
The colour of the sky very much depends on time of day and local conditions. On Earth we're used to Rayleigh scattering giving us a lovely blue sky. On Mars, however, Mie scattering dominates most of the time, giving a pinkish sky and bluer sunsets. A Martian day that's exceptionally clear of dust (...
- Fri Dec 10, 2010 1:43 pm
- Forum: The Library: Information Desk and Educational Resources
- Topic: Best ways to identify what I see at night
- Replies: 13
- Views: 1263
Re: Best ways to identify what I see at night
Download and install Stellarium. It'll show you on your computer screen what you can also see outside, and can identify most objects.
- Fri Dec 10, 2010 6:50 am
- Forum: The Science Labs: Participate in Citizen Science or Smartphone Science
- Topic: Fireball48 Alert: Fireball Over the United Kingdom
- Replies: 56
- Views: 35622
Re: Fireball48 Alert: Fireball Over the United Kingdom
I didn't see a damned thing from South Yorkshire and I was out observing for a cluster of Iridium flares at the time.
Also that phone image looks really, really fake.
Also that phone image looks really, really fake.
- Wed Dec 08, 2010 7:16 am
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: APOD: Intrepid Crater on Mars (2010 Dec 08)
- Replies: 17
- Views: 4368
Re: APOD: Intrepid Crater on Mars (2010 Dec 08)
As far as I know, "impact basin" is a specific term for a crater much larger than 20m!
- Wed Aug 25, 2010 2:11 am
- Forum: The Library: Information Desk and Educational Resources
- Topic: Can "cause & effect" travel faster than the speed of light?
- Replies: 33
- Views: 3637
Re: Can "cause & effect" travel faster than the speed of lig
Then how do we ever move beyond existing theory? If everything has to happen within existing theory, doesn't that preclude being able to move beyond it, by definition? Would you say that relativity is 'within the bounds' of Newtonian mechanics? Thing is, everything has to happen within existing the...
- Wed Aug 25, 2010 2:00 am
- Forum: The Library: Information Desk and Educational Resources
- Topic: TWAN: Solve a Mystery
- Replies: 8
- Views: 5407
Re: TWAN: Solve a Mystery
Almost certain that "Mystery 1" is atmospheric gravity waves, especially given that there are mountains very nearby. Mystery 3 is quite obviously a constellation of satellites flaring. The second one could be a failed missile or rocket launch/test, the fan shape is can be formed by a disin...
- Tue Jun 22, 2010 9:10 pm
- Forum: The Library: Information Desk and Educational Resources
- Topic: Solved: What is it? Space mystery object
- Replies: 457
- Views: 34574
Re: GRED: Double slit with sharp eyed intruder
I've actually done this with a very low power laser and welding glass. I wanted to know if I could see the laser being brighter or darker as I moved along it. So I vote based on that.
Edit: Beyond, that's just an artifact of how the diagram is drawn. You're seeing a side view, not a top view.
Edit: Beyond, that's just an artifact of how the diagram is drawn. You're seeing a side view, not a top view.
- Wed Jun 16, 2010 9:05 pm
- Forum: The Library: Information Desk and Educational Resources
- Topic: GRED Answer: Double slit with fast lensless video screen
- Replies: 56
- Views: 7662
Re: GRED Answer: Double slit with fast lensless video screen
Even if the photon passes through only one slit (e.g. experiments done with single photons at a time), it still produces an interference pattern as we can consider it to be interfering with virtual photons. This is simply a high-tech take on the one photon at a time experiment which has been done an...
- Fri Jun 04, 2010 7:33 pm
- Forum: The Communications Center: Breaking Science News
- Topic: SpaceWeather: New (2010 June 3!) Impact on Jupiter?
- Replies: 14
- Views: 767
Re: SpaceWeather: New (2010 June 3!) Impact on Jupiter?
The state of the impactor is already known: A rocky body and not, like the last two, a cometary object. The lack of a ring around the impact site, caused by the low density of a comet, tells us this impactor was solid as far as the lower cloud decks.
- Mon May 17, 2010 12:51 am
- Forum: The Library: Information Desk and Educational Resources
- Topic: 2-body gravitational coupling
- Replies: 11
- Views: 1126
Re: 2-body gravitational coupling
No. AFAIK there are no candidates for captured binaries. The possibility of a capture through a 3+ body system is understood, but is extremely unlikely in practice. While not stars, we believe Triton (Neptune) was captured exactly this way. Neptune has a distinct lack of larger moons and Triton was...
- Sat May 15, 2010 10:43 pm
- Forum: The Library: Information Desk and Educational Resources
- Topic: Local Group?
- Replies: 6
- Views: 1017
Re: Local Group?
I think that this statement depends on how you define "gravitational bound". All massice objects are affected by others' gravity. If there's a lot of empty space around the cluster, the gravitational bound of a galaxy to the group is stronger because there's no opponent. Otherwise if ther...
- Sat Apr 24, 2010 10:18 pm
- Forum: The Observation Deck: Latest Sky Photography
- Topic: Potpourri Poll #4 (Vote for your favorite image!)
- Replies: 7
- Views: 2634
Re: Potpourri Poll #4 (Vote for your favorite image!)
Not a vote for any (I voted for "Mystic Mountain") but a vote against. NO RAW IMAGES. Seriously. APOD, to me, is an example of the best of astronomical images. Raw images plain aren't. If I want raw images, I know where to get them and what news sources will give me them. If I don't know t...
- Tue Apr 06, 2010 9:57 am
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: APOD: Prometheus Remastered (2010 Apr 05)
- Replies: 10
- Views: 1718
Re: APOD: Prometheus Remastered (2010 Apr 05)
You shouldn't hotlink images from Something Awful. They tend to get very NSFW very quickly.
- Sun Apr 04, 2010 11:59 pm
- Forum: The Library: Information Desk and Educational Resources
- Topic: Solved: What is it? Space mystery object
- Replies: 457
- Views: 34574
Re: Space mystery object #30
In this case, I don't believe the OP indeed has provided enough for anyone to solve it by any means other than brute force or dumb luck.
Though I personally am yet to try. I'll give this a go tomorrow when RL is less of a burden.
Though I personally am yet to try. I'll give this a go tomorrow when RL is less of a burden.
- Sun Apr 04, 2010 11:17 pm
- Forum: The Library: Information Desk and Educational Resources
- Topic: Solved: What is it? Space mystery object
- Replies: 457
- Views: 34574
Re: Space mystery object #30
I think we need a standard size for crops, some are just too small, like this one, to make for a reasonable challenge.
Making a stupidly small crop just makes it easy on the challenge poser.
Making a stupidly small crop just makes it easy on the challenge poser.
- Mon Mar 29, 2010 8:39 pm
- Forum: The Library: Information Desk and Educational Resources
- Topic: Local Group?
- Replies: 6
- Views: 1017
Re: Local Group?
That very much depends on your definition of "part of". We are gravitationally bound to it but this was not always the case[1] and will not always be the case[2]. For example, between us and the Virgo Cluster is the Canes I Group and the M81 Group. [1] We're on the very outskirts, which li...
- Fri Mar 26, 2010 10:49 pm
- Forum: The Library: Information Desk and Educational Resources
- Topic: Massive blue giant stars after the first 700 million years.
- Replies: 8
- Views: 1560
Re: Massive blue giant stars after the first 700 million yea
There are two schools of thought in galaxy formation (no, you can't escape it!). The first one I'll discuss is "stars came first" that a cluster of stars used their gravity to draw in more material and so set off galaxy formation. The central black hole simply sank there and absorbed more ...
- Fri Mar 26, 2010 10:58 am
- Forum: The Library: Information Desk and Educational Resources
- Topic: Solved: What is it? Space mystery object
- Replies: 457
- Views: 34574
Re: What is it? Space mystery object #24
The Javascript code is here if anyone wants to use it locally.
makc's PHP version is more elegant than mine (and should be used as first preference), but won't work on some servers (such as mine!) which don't let PHP play with headers. Code for that is here.
makc's PHP version is more elegant than mine (and should be used as first preference), but won't work on some servers (such as mine!) which don't let PHP play with headers. Code for that is here.
- Fri Mar 26, 2010 10:49 am
- Forum: The Library: Information Desk and Educational Resources
- Topic: Binary stars in a supernova explosion.
- Replies: 7
- Views: 1412
Re: Binary stars in a supernova explosion.
No, it doesn't.
- Fri Mar 26, 2010 4:33 am
- Forum: The Library: Information Desk and Educational Resources
- Topic: Binary stars in a supernova explosion.
- Replies: 7
- Views: 1412
Re: Binary stars in a supernova explosion.
For talking purposes assume the non-exploding star is like the Sun and 60 Sun radii apart from the supernova star. That's difficult since a star like the Sun can never explode. What possible calculations and/or logic could be used to estimate whether the subject star increased or decreased in size ...
- Thu Mar 25, 2010 10:35 pm
- Forum: The Library: Information Desk and Educational Resources
- Topic: Solved: What is it? Space mystery object
- Replies: 457
- Views: 34574
Re: What is it? Space mystery object #24
Random APOD (Javascript version, use this) Random APOD (HTML version, doesn't work well with browser caching) Won't work right during some hours as APOD doesn't use UTC. It may give you "today" by UTC but APOD is still "yesterday". I should imagine that to be fairly rare, though.
- Thu Mar 25, 2010 10:15 pm
- Forum: The Library: Information Desk and Educational Resources
- Topic: Solved: What is it? Space mystery object
- Replies: 457
- Views: 34574
Re: What is it? Space mystery object #24
That gives me an idea. I could do this on my web server.
Coding time!
Coding time!