"The Science Hour" Questions wanted !

[gaa_ian (Ian)]

As some you may know I host a weekly science program "The Science Hour" on our local radio station http://www.govefm.com.au

I am very keen to get some new Astronomy and space science questions that will appeal to the general public.

I have done some of the obvious ones over the first 6 weeks of my show.
EG: Why is the Sky Blue, The moon illusion, Dark Matter, Big Bang theory, moon moving away, What are sunspots, Is there life out there. + a number of pure science questions & the latest, kids science experiments.

Short sharp questions are best.

Questions will be asked on air ....... EG:
Ken asks, why do the clouds always come over when I buy a new eyepiece ?

Then I spend the next five minutes explaining the inverse ratio of accessory cost to % cloud cover

I am in the process of setting these Q&A's up as podcasts, I will post the links to these on IIS for any of your questions that I use
Here is an example from my second show
http://www.govefm.com.au/science%20h...science%20.mp3

Bring it on ......

[g__day (Matthew)]

You asked for it!

How close was the Moon to Earth when the dinosaurs where alive - would tides have been monumental then and how would it have affected life on Earth?

Explain why if Jupiter and/or Saturn weren't in our solar system complex life evolving on Earth might not have been possible.

Relativity may not hold between galaxies - is dark energy or MOND more likely to be right?

From the SLOAN sky survey we structures in space that have a fractal pattern but are a size 10 times past the limits that relativity could apply (10 million light years) - discuss is it likely all spacetime is fractal? (a.k.a. scale-relativity)

Explain why if our solar system was further in or further out on our galactic arm - complex life would have been at greatly increased risk to survive?

Explain why if Earth was about 15% lighter complex life would have been unlikely to survive.

Explain how wierd spacetime expanding - rather than distant galaxies just receding really is!

For advanced life to exist about 32 independent variables have to fall within acceptable ranges (e.g. planet mass, planet position, presence of water, silicate balance, plate tectonics) explain just how incredibly unlikely are the chances of finding an environment where advanced life can prosper.

Under relativity the speed of light as an absolute limit to the rate of information exchange appears incredibly well proven, but introduce the environments where or when relativity may not hold sway and explain why it is so hard for us to study these regions (the big bang before inflation, within a black hole's event horizon, the empty space between galaxies (maybe), the world at quantum (Planck) scales of reality, ultra high energy density domains etc.

[gaa_ian (Ian)]

Thanks G_Day
Lots of material to work with there !
I have some research to do

Why is it so .....

[Dujon]

Ian,

A little more prosaic than G'day's.

Q: The speed of light is generally accepted to be constant, at least through a vacuum. We are also told that the speed of light varies should the light pass through a different medium.

In view of the fact that it is believed that space is not really empty is it possible that the red and blue shifts recorded by astronomical instruments are in some way being corrupted by our reliance on the 'given' speed whilst ignoring possible intervening events between distant sources and our sensors?

[okiscopey (Mike)]

If it's for the general pooblic, how about:

Why do professional astronomers never look through telescopes?

What did Galileo do wrong?

Can spiders build webs in zero gravity?

What happens after the Hubble Space Telescope stops working?

What happened to poor old Pluto?

Where are we going to live on the Moon?

Why do some astronomers work underground?

What is a planisphere? (or, How do you find your way around the sky?)

? Something on aboriginal sky lore ?

What else? That's about it for the moment!

[Glenhuon (Bill)]

Ian. For some of the answers research a listen to selected lectures in the Astronomy 161/162 podcasts might help. ( or go through them all, they are excellent )

Bill

[gaa_ian (Ian)]

Thanks All
Heaps of great material there !
I was thinking that the Astronomy 161/162 looked like a good thing.
I will have to download it.

[g__day (Matthew)]

If you want the summary answers too - just say! For the easy ones:

How close was the Moon to Earth when the dinosaurs where alive - would tides have been monumental then and how would it have affected life on Earth?

The first stable orbit for the Moon after its initial formation was likely around 20,000 km (for the impact / capture model). Dinosaurs where around circa a few billion years after that - so simply work on a recession rate of 4 inches a year for 300 million years back from where the moon is today. This means the moon would likely be about 30,000 km closer to the Earth when Dinosaurs roamed then it was today (around 10% closer). Gravity falls away with a square of distance effect - so gravity might have be 19% stronger - tides may have been 19% larger.


Explain why if Jupiter and/or Saturn weren't in our solar system complex life evolving on Earth might not have been possible.

They would have sucked up rogue comets, asteriods and debris that would have been plentiful when early life was forming. If they hadn't many Earth Level Extinction Events could well have wiped out life on Earth. So in essence they act like giant vaccuum cleaners removing dangerous objects left around after solar system formation.


Explain why if our solar system was further in or further out on our galactic arm - complex life would have been at greatly increased risk to survive?

The heart of our galaxy is an exciting place - dangerously exciting. Star formation and termination is rife given the far greater density of stars. These stars go novae sometimes releasing alot of hard radiation - the life killing kinds even at great (astronomical) distances. However radiation helps mutation helps gradual evolution of life. So if our solar system was too far out radiation may not have been strong enough to help create simple life. Too far in and too much activity from supernovae would have sterlised life forming organisms.


Explain why if Earth was about 15% lighter complex life would have been unlikely to survive.

Gravity at the top of our atomsphere would be just a bit weaker and low enough for atomic hydrogen to significantly escape into space. At present over our oceans some water vapour is broken into atomic Hydrogen and Oxygen by ultra violet radiation. But these gases eventually re-combine - so the Earth's atmospheres and its oceans system is stable. For a lighter planet e.g. Mars - gravity is lesser than the critical point where it can retain atomic hydrogen - so eventually it lost all Hydrogen and that means you loose all water too. No water - no medium for life to mix and evolve!

[gaa_ian (Ian)]

Thanks G_day
I will certainly use those, they are great Q&A's and I am sure I can expand on them !
I have just completed my first science hour Audio compilation ready to release to the podcasting world & I will release it as soon as I figure out the hosting and upload etc.
You guys will be the first to know once it is up
Cheers
Ian