VIDEO: Nicolas Copernicus Reburied

VIDEO: Newton's 3rd Law by Veritasium

There is a gravitational force of attraction between the Earth and the moon, but is it mutual? That is, are the forces on the Earth and the moon equal? Most people would say no, the Earth exerts a greater force of attraction because it is larger and has more mass. This is a situation in which Newton's Third Law is relevant. Newton's Third Law says that for every force, there is an equal and opposite reaction force. So the force the Earth exerts on the moon must be exactly equal and opposite the force the moon exerts on the Earth. But how can that be - that the same size force keeps the moon orbiting, but barely affects the Earth? The answer is inertia - the tendency for all objects with mass to maintain their state of motion. Since the Earth has much more mass than the moon, it has greater inertia and therefore experiences much less acceleration for the same amount of force.

link to video on YouTube

VIDEO: Why Does the Moon Orbit Earth? by Veritasium

See! Sometimes people get it right! :-)

VIDEO: Scale Model of the Earth and Moon by Veritasium

If the Earth were a basket ball and the Moon a tennis ball, about how far apart would the balls need to be to accurately represent the distance between the Earth and Moon with a scale model?

In the News: Space Shuttle Discovery

ABC: Shuttle Discovery Makes Its Final Landing

SONG!: "My Favorite Star" from Bill Nye

LYRICS

It's a supercharged ball of gas
I'm talkin' about the sun
Makin' energy with a solar blast
Fusion's so much fun
Ooh, it's a power plant
Heating up everything
Cars and rocks and nuclear plants
Ballerinas and baseball swings

Exploding
And fusing
And rocking
And rolling
It's my favorite star!

Solar winds blow through the air
The northern lights look nice
More sunspots mean hotter Earth
Less spots mean cold as ice
Ooh, it's a real hot shot
But doesn't radiate heat
Earth absorbs the sun's rays
And makes heat, ain't that neat

Exploding
And fusing
And rocking
And rolling
It's my favorite star!

SONG!: "The Case for Mars" by Symphony of Science

LYRICS

(Carl Sagan's lyrics written by Carl Sagan, Ann Druyan and Steven Soter)


[Robert Zubrin]
Mars is the next logical step
In our space program
It's the challenge that's been staring us in the face
For the past 30 years

It has water, it has carbon,
It has a 24 hour day
It has geothermal energy
Mars is a place we can settle

[Carl Sagan]
There is a giant rift in its surface
5,000 kilometers long
There is a volcano as wide as Arizona

[Zubrin]
So there's the choice in life
One either grows or one decays
Grow or die
I think we should grow

[Sagan]
Mars is a world of wonders

[Brian Cox]
It has canyons, river valleys,
and giant ice sheets

[Sagan]
Mars is a world of wonders

[Zubrin]
It shouldn't be humans to Mars in 50 years
It should be humans to Mars in 10

We either muster the courage to go
Or we risk the possibility of stagnation and decay

We've got cosmic radiation
Zero gravity
Martian dust storms
Back contamination

But these are dragons that we can take on

[Sagan]
In our time we have sifted
The sands of Mars
Established a presence there
And fulfilled a century of dreams

[Cox]
The Mars rovers have really
Captured our imaginations
They genuinely are explorers
In the old-fashioned sense

[Zubrin]
If you put out a call
For volunteers for the first crew to Mars
They'd be lined up coast to coast

(refrain)

[Cox]
Mars is a dry frozen version of our home
Covered in red dust and sand

[Penelope Boston]
At one time
In the ancient past
Mars was very similar
To the conditions of early earth

[Zubrin]
There will always be people with new ideas
On how humans should live together

[Cox]
We now have "eyes" and "ears" on the surface

[Zubrin]
What's left after you go is
The good you've left behind
You have to believe in hope
You have to believe in the future

There are more and more people coming around to the point of view that
A positive future for humanity requires human expansion to space

(refrain)

We're at a crossroads today
We either muster the courage to go
Or we risk the possibility of stagnation and decay

Science in the News

This week's issue of Scholastic News is packed full of science! First we learned about the Kepler Telescope, which is searching for Earth-like planets that might have liquid water. Why do scientists care that the water is in liquid form?

Check out these NASA videos about the Kepler mission (the first one is much shorter than the other)...





We also saw a picture of a deep-sea fish that seems alien to us because its so strange. You can actually see through its head! And it can too!-- because its eyes are on the inside. Its transparent (see-through) forehead acts like the canopy of a jet or the windshield of a car, protecting its tubular eyes. Pretty nuts!



Finally, last week we saw that the cover of the Washington Post had a picture of a new arrival on the front page... Here's some video of those precious little guys: