Q & BA Questions thread

[The Bad Astronomer]

This thread is for questions BABlog readers have for me for the "Q & BA" feature on the Bad Astronomy Blog. If you have a question, post it here along with your name and region if you want me to use them (otherwise I'll use your BAUT handle).

Try to be succinct! I'll be reading the question on the video, and I might have to paraphrase.

Enjoy, and thanks!


Phil Plait, aka The Bad Astronomer

[ritchards]

Okay, I'll go with a question (and, oh, my first post here!):

We know(*) that black holes exist, but what about white holes? Do they exist? Could they even theoretically exist?

(*) For a given value of "know".

Hmm...now, do I want to give my real name, being pretty sure you won't be able to pronounce it properly... let's see:

Jamas Enright, Wellington, New Zealand
(Jamas is like Shamus, but with a J.)

[Serenitude]

I have a question. With space expanding faster than the speed of light, does a photon moving through space move in what a removed observer would see as a straight line, or is a photon moving through space affected by the expansion of space (ie, a straight line through expanding space, which to a removed observer would not appear straight?), and is this taken into account in observations of distant objects. Why or why not is light affected by expanding space?

[Sticks]

Change of pace here, although I suspect it may have been covered in astronomycast so we are after your take on this one.

How do you get started in astronomy, what kind of equipment should you start out with, what is the best way to use a scope, (especially if you wear glasses do you look through the eyepiece with your glasses on or try and focus the eyepiece to your prescription)

And finally how can the dedicated ameteur contribute any discoveries to the main bodies of science.

forgot to add

Graeme Stickings - Newcastle upon Tyne, England

[Laguna2]

Could you answer me where the ultra high energy cosmic "radiation" (I know its particles) comes from. I heard a video blog about it several years ago, but the astronomer said, back then, they where not quite sure about it and just had some ideas.

Martin Köster, Reiskirchen, Germany

[maryccc]

Can you explain galaxies to me. What is the easiest galaxy to view through a telescope and can I find a galaxy in my cheap tasco telescope? Will I actually be able to see it. I have heard that many galaxies have collided with us and we have eaten them up but will we ever be eaten up by another bigger and stronger galaxy? What does a galaxy consist of?

[Thad Hatchett]

I'll throw my hat in with a first time post. I have a timely question about comet McNaught. I read in a couple of places where comet McNaught was visible (at that time, unfortunately no longer) as both a morning comet and an evening comet. How could any object that sets after the sun, possibly rise again the following morning prior to the sun? Space.com listed both morning and evening finder charts.

Appreciate the help!

Thad Hatchett
Columbus, IN

[Grand_Lunar]

Here's one that really has had me scratching my head:

Why does Saturn's moon Titan have a thick atmosphere, but Jupiter's Ganymede does not, even though they are similar in size (both being larger than Mercury)?

(you might have trouble with my last name. pronouced "okra-gles-key")

Scott Okragleski
Fort Lauderdale, FL

[George]

1a) Care to offer a general heliochromological prognostication? [You might explain why false color is indeed far superior to troublesome true color, too.]

1b) Due to solar atmospheric opacity issues, the central region of the solar disk is 1390K hotter in appearance than the limb (~6390K vs. 5000K), so would the solar disk not appear to have a slightly bluish-white center? [Assumes an astronaut is seeing the sun from space and at a light level within the normal photopic range of the eye.]

2) Will the classification of stars ever be revised significantly?

[rdaneel]

As an astronomer, what is your take on the recent spate of books criticizing string theory's dominant position within physics? This would seem relevant to cosmological theories that are highly relevant to astronomy. I am thinking here of Lee Smolin's book "The Trouble with Physics", and Peter Woit's book "Not Even Wrong".

[Dr Nigel]

Here's a couple* for you to think on, BA:
1) How were gamma-ray bursters first discovered/noticed/identified?
2) What are they?
3) How did we find this out?

Nigel Depledge
County Durham, England

*Edited to add: alright, three.

[Sticks]

Originally Posted by Dr Nigel

Here's a couple* for you to think on, BA:
1) How were gamma-ray bursters first discovered/noticed/identified?
2) What are they?
3) How did we find this out?

Nigel Depledge
County Durham, England

*Edited to add: alright, three.

apologies for stealing Phils thunder on this one, but I posted a link here to a Horizon programme that covers this.

[JonFM97]

I was wondering about your opinion on the idea that the universe is not only stranger then we image but stranger then we can image. I know that's more of a Cosmology question but I'd like to know what the general opinions are among the scientific community on this idea. Thanks.

[Mr. Maxwell]

I am a 4th grade math and science teacher. One of my students, Ashllee Garza, (it would be cool if you could say her name on your reply) asked me, "Why is it the larger planets that have the rings around them, not the smaller ones?"

I told her that I thought it was because the larger planets have stronger gravity allowing them to grab more stuff as it floated by, thus forming rings, but that I should probably ask a real astronomer.

Hope you choose this question.

Regards,
Jason Maxwell
Houston, Texas
Tipps Elementary

[bassmanpete]

How do spacecraft make use of the slingshot effect? I can understand how the pull of a planet will accelerate the craft but once it's passed by won't the planet decelerate it by a similar amount? Or does the craft fire it's rockets to add to the effect?

[Matty]

I have read that if you take a teaspoon of a neutron star it will weigh around 1000kg.

My question is that if you could actually extract a teaspoon of neutron star, what would happen to it?

[thaumaturge]

What did you think of the "supernova" depicted in the recent Battlestar Galactica episode (3x12)? It seemed kind of hokey to me.

[satori]

I threw this question allready at the community but got little resonance :
What about blowing a (glas-) bubble in space to confection a HUGE spherical mirror.... Could that work ? Could it be of any use ? Is that a total whacky scrab sort of an idea ?
Assemble an expert commission , please .........
(and remember you got it from me )

[Charlie in Dayton]

Do we 'celebrate' the beginning of the seasons on the wrong days?

The traditional first day of summer is around June 21, the 'longest day' of the year...but that ought to be the MIDDLE of summer, being the high point of the curve...

The traditional first day of winter is around December 21, the 'shortest day' of the year...but that ought to be the MIDDLE of winter, being the low point (so to speak) of the curve.

Some quick calculations and/or googling the concept 'cross quarter days' gives us the following information and "corrected" seasons:

A cross-quarter day is a day falling approximately halfway between one of the four main solar events (two solstices and two equinoxes) and the next one. These originated as pagan holidays in Northern Europe and the British Isles, and survive in modern times as neopagan holidays.

The cross-quarter days traditionally mark the start of spring, summer, autumn, and winter, respectively, and are:

* Imbolc or Imbolg (February 1) RELIGIOUS: Candlemas
* Beltane or Bealtaine (May 1) Walpurgis Night (Apr 30) / May Day (May 1)
* Lughnasadh or Lunasa (August 1) Lammas
* Samhain (November 1) Halloween (Oct 31), All Saints' Day (Nov 1), All Souls' Day (Nov 2)

Technically, the cross-quarter day is the start of a season -- the equinox or solstice marks the MIDDLE of a season.

Summer Solstice -- June 21
Winter Solstice -- December 22
Spring Equinox -- March 20
Autumn Equinox -- September 20

NOTE -- the above are for the Northern Hemisphere. In the Southern Hemisphere, the Equinox seasons are reversed -- Spring in Sept, Autumn in March

The Year Wheel
Winter Solstice -- December 22 -- midWinter
Imbolc -- February 1 -- first day of Spring
Spring Equinox -- March 20 -- midSpring
Beltane -- May 1 -- first day of Summer
Summer Solstice--June 21 -- midSummer
Lughnasadh -- August 1 -- first day of Autumn
Autumn Equinox -- September 20 -- midAutumn
Samhain -- November 1 --first day of Winter


SO -- are our seasonal celebrations about 45 days off from where they really ought to be?

Charlie Cotterman
Dayton OH

[Charlie in Dayton]

Originally Posted by maryccc

Can you explain galaxies to me. What is the easiest galaxy to view through a telescope and can I find a galaxy in my cheap tasco telescope? Will I actually be able to see it. I have heard that many galaxies have collided with us and we have eaten them up but will we ever be eaten up by another bigger and stronger galaxy? What does a galaxy consist of?

I'm going to steal a tad of the BA's thunder too...
1 -- the easiest galaxy to see at all is the Milky Way, because we're inside it. It's visible to the naked eye on a dark night as a band of stars running from Sagittarius up across the sky to Canis Major on the other side, according to my northern hemisphere star wheel (the MW continues on past these constellations, but is below the horizon then).
The easiest galaxy to see other than ours is M31, the Andromeda Galaxy. It is approximately 2.7 million light years away (ballpark math -- 186,000 miles per second X 60 seconds X 60 minutes X 24 hours X 365 days x 2,700,000 = miles), and is the furthest object visible to the naked eye. It is visible to the naked eye on a dark nite from a dark site, and easily visible even in small binoculars (the ubiquitous 7x35's).

2 -- in a few odd billion years or so, if I have the figures correct, the Andromeda Galaxy and the Milky Way will "collide" and rearrange each other. At this stage, no one's sure if the end will be two new galaxies, or one. See below for additional on this.

3 -- a galaxy consists mostly of empty space, so there are few if any actual planetary/star collisions. Other than that, there are hundreds upon thousands of stars (and there's no doubt that some of those stars have their own planets), and large clouds of dust and gas. There is a lot of change in orbits due to gravitational interactions, but there's not expected to be anything(s) running into each other.

Hope this helps, and an in-advance 'sorry about that, chief' to the BA if i'm in error somewhere or a toe got stepped on.

[VoijaRisa]

Here's a simple but rather deep one that I think might be worthwhile:

How has being a skeptic improved your life?