Mars Exploration

Prof. David Cohen, Swarthmore CollegePresentation 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