Ask the Astronomer!

[Bill McBlueState]

I used to work at a planetarium, and I kinda miss fielding questions from the public.

What questions (astronomy or otherwise) can I answer tonight for DU?

[PragMantisT]

1. What's your sign?

Just kidding.

Will we be able to see the transit of Venus in the states?

[Bill McBlueState]

3. in the eastern US

In the eastern US, the Sun will rise with Venus already in transit. It'll be over before the sunrise in the western US.

There's a map here: http://skyandtelescope.com/observing/objects/planets/article_1021_2.asp

[PragMantisT]

6. Thanks WMa

You're a good sport.

Looks like there's more demand for astrologers. Ever thought about going back to school to become an astrologer?

[FarmerOak]

2. Question:

I heard somewhere that Venus will be crossing in front of the sun soon. With that in mind, should I be dating a Sagittarius? I am a Gemini, but I'm sort of on a Taurus cusp, and sometimes I feel a lot of Taurus influence.

P.S. - I think it's great that you guys ran the whole Reagan administration.

[Bill McBlueState]

4. lol

here's your Onion horoscope, btw

Gemini: (May 21—June 21)
The more you think about it, the more you like the idea of having 12 young men dance around you at all times—as long as it's tastefully done.

[kaos]

5. A question about the big bang?

Was the Universe born in a Black Hole?
http://www.eurekalert.org/pub_releases/2003-09/uoc--wtu091603.php

What do you think?

[Bill McBlueState]

9. this is complicated

Determining how the universe started is probably well beyond the range of any experiment we could do in the foreseeable future.

So the questions we have to ask of any explanation are

-does it make sense mathematically? (This black hole idea seems to.)

and

-what can we observe in the modern-day universe to confirm or deny this hypothesis?

That second point is where these ideas tend to stall. If the authors could show how their theory predicts something that's seen in the universe today, their idea would gain acceptance.

[kaos]

38. Black holes..

It took me awhile to get used to black holes but I always had that nagging doubt, what happens to all that energy when it disappears passed the event horizon?

I understand we can never test what is happening inside a black hole,but it is a nifty little theory..

Thank you for your comment I do not comment much as I am trying to stay in the 700 club..

[Bill McBlueState]

43. the energy

what happens to all that energy when it disappears passed the event horizon?

That's the goofy thing; it just gets lost in there. Although through the mechanism Stephen Hawking proposed, that energy can eventually make it back to the outside universe. crazy stuff!

[kaos]

47. goofy thing.

Energy has to go someplace....

[xray s]

7. Where is the comet?

I was looking for it last night, no luck. Does it have a visible tail, or is it only a smudgy looking "star"?

[Bill McBlueState]

11. hmm...

They say it's 3rd magnitude, so it shouldn't be *too* hard to spot. That's about as bright as the star at the center of the northern cross (Cygnus). But at that brightness, I don't think the tail will be easily seen.

I haven't had a chance to spot it yet, either.

But I do have a friend who's in Hawaii right now, observing it with a radio telescope. Wish I could be there!

[Blue-Jay]

8. What's the shortest amount of

time that it would take to reach the closest star at sub light speed?

That's more of a physics question, isn't it?

[Bill McBlueState]

12. 4.5 years at light speed

At 180,000 miles per second (the speed of light), you'd reach Proxima Centauri in 4.5 years.

I'm not sure how fast our probes, etc., go today, but it's wayyyy slower than that.

[kodi]

10. if stars been shining for billions a years why ain't the whole sky lite up

trick question.

[Bill McBlueState]

13. cuz Shrub's mom is in the way.

(sorry)

[kodi]

41. that's your answer?

.

[Bill McBlueState]

44. seriously, that's the reason!

well, since we're on the topic, it's because the light from most stars hasn't had time to reach us since the beginning of the universe.

:)

[Canuckistanian]

14. Why does only one side of the moon face us here on Earth?

[Bill McBlueState]

16. synchronous rotation

The time it takes the moon to spin on its axis is exactly the same as the time it takes to go around the earth once. Picture that and you can see why the same side always faces us.

The reason *that* happens is that, after billions of years, tidal forces due to Earth's gravity have made the moon a little bit lopsided. Then the heavier side of the moon stays closest to Earth.

[Canuckistanian]

19. Thanks! One more moon question...

Why is it that during a solar eclipse, the moon seems to be the exact same size as the sun, more or less. Is this a coincidence?

[Bill McBlueState]

21. it's basically a coincidence

The sun is something like 400 times bigger than the moon, but it also happens to be exactly 400 times further away. So their angular sizes are almost the same, and they appear the same size in the sky. (about half a degree in diameter)

[Squeegee]

15. Loop Quantum Gravity or String Theory?

Which one do you favor in the Unified Field Theory Death-match?

[Bill McBlueState]

18. Quantum Gravity, with the point spread. n/t

[CrownPrinceBandar]

17. Do you believe the theory that c .....

may have been a different speed in the microseconds after the Big Bang?

[Bill McBlueState]

20. well, I guess the question is

what does that idea predict that can be observed in today's Universe?

I'm hesitant to buy any of these ideas, though, that the fundamental constants were ever different. (But that's just a philosophical argument, really.)

[CrownPrinceBandar]

37. My $0.02.................

While I agree that questioning fundamental constants puts research on a shaky ground, I believe that the BB was a wholly unique event. Imagine, all matter as we know it comes from what we understand as nothing. I can wrap my mind around the idea that c may have been different.

The guy who suggested it (Can't remember his name; he was French, I believe)got into hot water because of the constants it questioned. He said that blackholes would be different than we conceive of them now (spherical).

Interesting stuff. I love making my head swim with this stuff!

Thanks for answering! :thumbsup:

[Bill McBlueState]

40. non-spherical black holes?

that sounds really interesting!

[kaos]

45. BB

Are you trying to suggest we are special??

[Birthmark]

22. I sent you a PM.

Since I already know everything that there is to know about astronomy. HAH!

[Bill McBlueState]

25. got it!

and replied. :)

[flowomo]

23. still gonna change your DU name?

[Bill McBlueState]

24. maybe not...

I *am* sort of attached to my post count! It took some work for me to get into the 700 club.

[FarmerOak]

26. If men are from Mars, and Women are from Venus,

then what the heck comes from Uranus?

[Bill McBlueState]

28. "Dr." John Gray, of course

[FarmerOak]

33. I understand that he was married to Barbara deAngelis;

She is pretty hot; why does she have such low standards?

[Bill McBlueState]

39. I googled her

not bad, although her stuff sounds pretty foofy too.

[FarmerOak]

42. I'd like to google her my own self.

Seeing as how she has no standards, I mean.

[kaos]

49. Klingons...

n/t...

[ZenLefty]

27. If you could safely visit any celestial object...

...which one and why? What would you do there? How long would you want to stay?

[Bill McBlueState]

32. Europa

because we were specifically told not to in "2010: The Year We Make Contact"

Bring it on, highly-advanced alien civilization! :o

[kaos]

53. 2001..

Stick to the story we have not found the stuff on the moon yet we are still using a weapon...

[Squeegee]

29. black holes

Do you believe they are a singularity (entropy flows out of the universe forever), or do you believe them to be another form of ultra-dense matter with a surface at the event horizon (entropy stays in the universe at the horizon)?

[Bill McBlueState]

34. black holes

I'll say they're singularities.

eeks.. getting behind in my replies!

[Shananigans]

30. Why did I fail my college astronomy course?

[Bill McBlueState]

35. because your professor was incompetent!

Obviously! :toast:

[Shananigans]

50. You must be correct. Obviously! :)

[TrogL]

31. Anything good in the Northern Hemisphere right now?

I'm 53 degrees north.

It looks clear tonight. I've got a 200+ power scope.

[Bill McBlueState]

36. supposedly there's a 3rd-magnitude comet

but it may have set by now. I haven't managed to spot it yet myself.

http://skyandtelescope.com/observing/ataglance/article_110_1.asp

there's a story about it if you haven't seen it yet..

[Canuckistanian]

46. Are there variable stars with ultra-short (< 1sec.) periods?

I thought I heard about them once.

[Bill McBlueState]

48. variable stars

What I've heard is, the shortest period in which any object can change is the time it takes light to cross it. So for something to vary in one second, it has to be smaller than 300,000 kilometers across. (That's about 25 times the size of Earth.)

So typical stars, no. But you may be thinking of pulsars, which are the burned out cores of massive stars. They're the size of cities, and can have periods as short as a few milliseconds.

[lagniappe]

51. Hubble Deep Field.

I've always been fascinated by the Hubble Deep Field image. There seem to be hundreds of little dots which I assume are galaxies, right? If they are galaxies and the universe is expanding, shouldn't most of the dots be colored red (due to the red-shift)?

Here is a URL to one deep field picture.
http://hubblesite.org/newscenter/newsdesk/archive/releases/2004/07/image/a

[Bill McBlueState]

52. also a big fan of the HDF

Yes, all but a few of the objects in the field are galaxies. I think it's pretty amazing how each of those little dots could have a number of intelligent civilizations within.

You're mostly right about the redshift effect. The most distant galaxies will appear redder than they would if they were close. But that doesn't necessarily mean they'll be red in color. For example, a blue galaxy at a medium distance might appear yellowish but not quite red.

[BlueJazz]

54. Would it be possible (in the not to distant future)

to build a Telescope (space bound, of course) large enough to see life on other planets. I figure a scope with about 20 million power would be strong enough to detect life signs on a distant planet.

On Edit: I should clarify that. Detect life signs AT NIGHT on a distant planet. If we could see lights then there would be intelligent life.

[Angelus]

55. Hey....a fellow astronomer!

:hi:

Well, I'm not actually an astronomer. I'm just an amateur. Nice to see there's other people interested in this subject here on the DU!