Questions Show: Telescope Suggestions, Black Hole Energy, and Universal Time

Celestron telescope.

What starting telescope equipment does the Astronomy Cast team suggest? How much energy does a black hole generate? And how do we measure time outside the Earth?

If you've got a question for the Astronomy Cast team, please email it in to info@astronomycast.com and we'll try to tackle it for a future show. Please include your location and a way to pronounce your name.

Telescope Suggestions, Black Hole Energy, and Universal Time

Telescope Suggestions:

• Oceanside Photo and Telescope
• Telescope Reviews on Universe Today
• Orion Dobsonian Telescopes
• TeleVue Telescopes
• Celestron Telescopes

Would a black hole the same size as the sun give off the same amount of energy as the sun?

• Do black holes give off energy?  This articles says, perhaps, yes. — Wired
• The Isaac Asimov book Fraser talked about was likely in the Galactic Empire of the Foundation Series.  Anyone know which one?

How do we measure time if we leave Earth?

• Cesium Fountain Atomic Clock
• Episode #117:  Time

How do heavy elements like iron end up in the inner rocky planets but not in the outer solar system or in the sun?

• Gas giant planets could have core of iron and nickel – UK Astronomy Expert
• Sun does have some heavy elements, but a very small percentage — Cornell U
• Our Amazing Solar System — How Stuff Works
• Episode #123: Homogeneity w/Chris Lintott

Why doesn't a photon have mass?

• Photons do not have mass, but they have momentum — NASA
• Higgs Boson — CERN

Is an open universe infinite? What shape do we think the universe is? Did the early universe inflate at infinite speed?

• Geometry of the Universe — UTK
• Shape of the Universe — Wiki
• Episode #78:  Shape of the Universe
• Episode #79: How Big is the Universe
• Episode #58: Inflation
• What is the Universe expanding into? — Cornell U.

How to use binoculars:

• Binoculars for Astronomy — Universe Today
• How to Focus Binoculars – Appalachian Mountain Club

What are the processes that limit star size, and why don't black holes have that limit?

• Upper Limit on Star Mass-  Universe Today
• "Don't Supermassive Me:  Black Holes Regulate their Own Mass" — Universe Today
• Solar Radiation Pressure – Wiki

Is the expansion of the Universe caused by decaying matter?

• Dough and raisin analogy discussed here – Cornell U. (same as above)
• Paper:  Bulk Viscosity, Decaying Dark Matter and Cosmic Acceleration -- Astro-ph
• Conservation of Momentum — NASA

If the age of the Earth is derived from the decay of primordial material from when the sun condensed from a supernova, aren't we just dating the supernova and not the sun?

1. Chris Says:
   June 25th, 2009 at 7:17 am

   Aww, poor laptop R.I.P.

   Even from the next room I thought I heard my MacBooks fans running full speed just to realize It came from the audio. Gave me a bit of a shock

   Great show nonetheless. Now I just need to catch up with the older stuff ))

   cheers

2. Brian Patrie Says:
   July 4th, 2009 at 1:55 pm

   As far as i know, most of us who can't see autostereograms (and other virtual 3D tricks), also don't have normal binocular vision (and vice versa). So getting useful convergence out of a pair of binoculars is, at best, tricky. My brain doesn't have enough experience processing the dual inputs in concert—even when they're natural—to do it when they're artificial. (Having one astigmatic eye doesn't help, either.)

3. Brian Patrie Says:
   July 4th, 2009 at 1:58 pm

   Or, to more directly answer Fraser's question: I lean toward yes; we have trouble with binos, too.

4. Brad Says:
   July 8th, 2009 at 4:37 am

   In the same way a guitarist might need more than one type of guitar, a stargazer is likely to need more than one type of telescope. All the various kinds of scopes out there have their strengths and weaknesses. A good Maksutov will give excellent crisp contrasty views at high power, but it won't give a wide-field view. A Newtonian will give the lovely wide-field deep sky views, but it won't give a crisp contrasty planet. First, it would be good to decide what objects interest you most and buy accordingly. If you're like me, your first telescope will likely not be your last.

5. Wayne Alspach Says:
   July 12th, 2009 at 10:14 pm

   I own an Orion SkyQuest XT10 Classic Dobsonian Telescope and I have to say this is a very nice investment. Everyone in the family has learned to use it very well. My 8yr. old son loves to look at Orion and loves to talk about Orion's belt to his friends. I also suggest buying a Telrad finder and a 4" riser from ScopeStuff to keep the cheeks off the steel in the cold. I have to say aperture fever has kicked in and I am ready for a Meade 16-inch Lightbridge Dobsonian Telescope.

6. John Says:
   July 13th, 2009 at 9:24 am

   I just bought a 4.5" reflector and its fun, but I get quite a lot of satisfaction using the free stellarium program on my computer instead.

7. Rick @ Bushnell Telescopes Says:
   September 8th, 2009 at 6:05 pm

   Pretty nice post. I just came across your blog and wanted to say
   that I?ve really enjoyed reading it.
   I?ll be subscribing to your blog and I hope you post again soon!

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