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

[Laguna]

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?

[Brad.C]

Question: So how do astronomers decipher a "moving dot on a slide"?

Seems like every day someone is announcing some exciting new Kuiper belt object, discovered by seeing a moving dot in successive pictures of the same region of space.

These announcements, though, seem to always be accompanied by:

• A precise orbital path
• Distance from the sun
• Size of the object
• What the object is made of
• Rotational period
• Contents of any atmosphere

How do astronomers figure these things out? How accurately do they really know these figures? Are some of them just guesses?

Brad Corbin
St. Louis, MO

Follow up question along the same lines: If I had a big enough amateur telescope, could I discover new Kuiper belt objects? How can I tell if I'm seeing something someone else has already found, or if it is something new? If it is new, can I name it? How does that work?

[The Bad Astronomer]

The first Q and BA is now up!

Please let me know what you think. And keep sending me questions!

[crowman]

Hi Phil, hi everyone, I'm crowman aka. Rick.
This is my first time at B.A's.

There's one qestion bugging me for some time now:

SINCE SPACE-TIME IS EXPANDING, EVEN ACCELERATING
- HOW CAN GALAXIES COLLIDE?

Any Ideas?

rick

[crowman]

Rick again and by the way:
I just love this site
and Q&A is one heck of an idea, Phil! Great Work!

[Serenitude]

That was superb! Keep up the good fight!

[munky99999]

Hey, I heard you on Penn Jillette's radio show. You were pretty great. I then checked out your youtube blog and found this. Now I'm a pretty big geek and have done quite a bit of research.

I have 2 questions I can't seem to find an answer on these 2:

1. Now at the big bang. I thought it was a single infinitely small point. Smaller then a tip of a needle. However, more recently I have discovered that it was more like a very large mass which suddenly exploded. Which brings me to my question. How large was this very large mass? and did it just suddenly appear as a large mass?

[Hat Monster]

Computers are everywhere, aren't they?

Sojourner, for example, was a MIPS R1200 with a few megabytes of flash RAM, years before we started using flash RAM in our USB sticks.

Everyone here has a computer and most of us are quite interested in them.

Tell us, Phil, what computers go where, compare them to the home computer (Hubble uses a 486) and talk about how computers enable astronomers to do the astronomy they do. Talk to us about how CCDs are temperature dependent for noise and how a computer reconstructs the images on a CCD or CMOS sensor. Just a few ideas.

If you want to credit me, wayne at hattix.co.uk is both a decent credit and an email address that will find its way to me. But you don't have to.

[Sticks]

Are you still going to consider questions posted before the first Q&BA?

This one would benefit new entrants in to astronomy

[rwedens]

I have a question. I have heard some answers to it but I still do not fully understand, so some help would be appreciated. The question: When we look at a galaxy and determine it is, let's say 10 billion light years away, that means the light left that galaxy 10 billion years ago and has taken that long to get to us. If the Big Bang happened (using round numbers) 14 billion years ago, how did a galaxy get 10 billion light years away from us in only 4 billion years? I know it has to do with the expansion phase and the fact that space itself is expanding, not just objects in space, but it still does not make good sense to me. How long was the rapid expansion phase? How far did the early universe expand during that time? And how fast is space expanding now? Thanks in advance for the help. Love your web site and thanks for turning me on to the Skeptics Guide to the Universe. That is a great pod cast.

Richard.