Download westtown_12feb04 - Astronomy at Swarthmore College

Mars Exploration
Prof. David Cohen, Swarthmore College
Presentation for Westtown Lower School
February 12, 2004
What is astronomy?
Study of the stars, moon,
planets, sun & everything
else in outer space
When we look up in the
sky at night, we see
mostly stars…but
ancient people noticed a
few “stars” that
wandered around the
sky over the course of
the year; the ancient
Greeks called them
planets
MARS
The Moon is the biggest thing we usually see in the night sky
Questions we want to think about today:
•What are planets like?
• How big and far away are the planets, especially Mars
(and let’s compare this to the Moon)
•Are there good conditions for life on Mars? Now? In
the past?
• How are we exploring Mars and what are we finding
out?
Stonehenge in England: over the years, people have built
monuments to the sky, and observatories for watching it
Today’s observatories are big telescopes on mountaintops
And even spaceships: This is Apollo 11 about to
land on the Moon
See the Earth in the distance?
Artist’s vision of a spaceship landing on Saturn’s moon Titan
And today, we’ve got robots on Mars discovering
what that planet is (and was) like
Artist’s conception of the rover Opportunity
Before we look at
what’s being
discovered on Mars,
let’s look at what
Mars is (and
compare it to the
Earth and Moon),
and also let’s look
at how big and far
away it is.
MARS
The Earth and Mars are just two of nine planets in
the solar system – planets are huge balls of rock,
metal, and gas.
Earth Mars
The Earth is a planet too – it’s a round ball, about 15,000
miles across, made up of rock, metal, water, air,…
The Earth, has an
atmosphere and
oceans – we
couldn’t have life
on Earth without
them
The Moon does not have any air or water: there is not and
cannot be any life on the Moon
Mars does have an atmosphere (though it’s thinner and
different than ours on Earth).
The big question is: Does Mars have water?
Gullies from running water in
the past?
Polar icecaps
To learn more, we’d like to go to Mars – first with robots,
then maybe with people
How hard is it to get to Mars?
The Earth and Mars are just two of nine planets in
the solar system – How big is the solar system?
Earth Mars
The solar system is big, and the planets are spread out
The solar system is so big…what if we
made a scale model of it?
The Sun (a million miles across) could be the size of a beach
ball.
The Earth (15,000 miles across) would be the size of a small
marble.
The Moon (half as big as the Earth) would be an even smaller
marble.
Mars is bigger than the Moon but smaller than Earth.
How far apart would the Earth and Moon be on this scale?
How far from the Sun would they be? How far away would
Mars be?
Picture of the Earth and Moon taken from Mars
A spaceship can fly to the Moon in a few days, but
to go to Mars takes more than a year.
Can you imagine going on a trip that took a
year…each way?
Mars launch movie
Artist’s rendition of one of the spaceships landing
NASA’s animation of the rovers’ entry into the
atmosphere of Mars and their landing
entry movie
Spirit
Opportunity
Exposed bedrock at the Opportunity landing site – very
old rock…is it sedimentary (meaning formed in water)?
Sedimentary rocks on the Earth
Opportunity photographing the
bedrock outcropping
Bedrock movie
Spirit checking out a rock
This picture taken by Opportunity is only an inch across
Could this small round pebble have been formed by water?
And another animation of the rover moving onto
the surface of Mars
Rover moving onto surface movie
Animation of the robotic rover
Robot animation
Come to the College’s telescope open house
the second Tuesday of each month at Sproul
Observatory at Swarthmore College.
More pictures of gullies on Mars…maybe caused by
water flowing on the surface of the planet
There are dormant volcanoes on Mars too
The so-called “face on Mars”
A better picture shows that it’s not a face at all