Mars Fever - Do
You See Red?
EVERYONE is talking about Mars! At this very moment, there are 4 spacecraft speeding their way to the Red Planet. Japan's Nozomi is set to arrive in early 2004. The European Space Agency's Mars Express with its Beagle 2 lander will reach Mars in December 2003. NASA's twin Mars Exploration Rovers will arrive January 2004. Amateur astronomers are spending many late nights at the eyepieces of their telescopes. "Who can spot it first over the horizon?" "Did you see the Polar Cap?" "Have you seen Syrtis Major in your 'scope?" "Look at that, isn't it awesome?"
So what's the big deal? Opposition - that's what. The big deal is that on August 27th, Mars will be closer to the Earth than it has been in 60,000 years. Mars will be less than 56 million kilometers from the Earth at that time. Earth's orbit is nearly circular. Mars' orbit is an ellipse. Opposition is the closest approach of Mars to the Earth in their respective orbits. At opposition, Mars and the Sun appear to be placed "opposite" in the sky. Opposition occurs approximately every 2 years or so. So why is this one closer? Well it's all in the timing. Right now, Mars is nearing its closest approach to the Sun. When an object reaches its closest point to the sun it's called perihelion. Mars has had a perihelion opposition with the Earth many times before, but this time the timing is perfect and Mars is just a smidge closer than ever. Mars and Earth are not only in the same neighborhood but we are practically across the street from each other. This is also the reason Mars missions launch every two years - near opposition. You save on time and fuel.
Stars show up as little pin points, while planets have a disk. Mars' disk is growing bigger and as the 27th approaches you can see the size change easily in a telescope. It over doubles its size in four months. To put this in perspective, though, remember even at it's biggest, Mars will still appear to be barely larger than half the size of Jupiter when seen though a telescope.
Astronomers know it's not just the size of the object but the "seeing" that counts. Seeing depends on the stillness of the atmosphere. Earth's atmosphere can change a clear steady view to blurriness in a millisecond - no matter what equipment you're looking through. What you see also depends on Mars' weather cooperating. At the last opposition two summers ago, Mars was covered in a planet-wide dust storm. Mars looked like a flat, colored disk. All its surface features were covered by the storm. There were a lot of frustrated people down here! So what do you need to view Mars?
Just use your eyes! If you live on the west coast of the U.S. like I do, Mars is rising in the south-east horizon around 9:30 PM. To find out when Mars rises for your time zone and location, go to http://www.marsbase.net/m/sunrise-sunset-marsrise-marsset.php. Mars is the brightest object in the sky. Unlike stars, which twinkle, planets shine with a steady light. Mars has an orange/red glow to it. Binoculars are one of my favorite tools to use when I lay back and view the night sky. You won't be able to see surface details using binoculars, but they are great for bringing out the planet's color. Even a small telescope (4-5 inches) will start bringing out surface details such as dark markings and polar caps. Below is an image I took of Mars on August 5th at 12:38 AM using my 8-inch Celestron telescope and a 12mm eyepiece. I held up my Sony 4.0 mega-pixel camera to the eyepiece, zoomed in a little, held my breath for forever and... voila!
Pretend Mars' disk is the face of a clock. You can see the white southern polar cap at the 10:00 position and a large dark marking crossing the center of the planet. The light marking next to the polar cap (towards 12:00) is Hellas Planitia, an enormous impact basin. The dark marking on the left side of the planet is Terra Tyrrhena and Hesperia Planum. The dark marking to the right (at 3:00) is Syrtis Major. If you go to http://mars.jpl.nasa.gov/gallery/atlas/ you'll see a map of Mars for comparison.
Have you ever wondered what the Earth looks like from Mars? The image to the right was taken from the Mars Global Surveyor spacecraft (MGS) http://mars.jpl.nasa.gov/mgs/ looking back at the Earth. MGS has been orbiting Mars doing science and sending back images for the last six years. On May 8, 2003, for the first time, the principal investigators decided to turn the spacecraft to face the Earth and take an image of our home planet: http://www.msss.com/mars_images/moc/2003/05/22/. At the time, Earth was 139 million kilometers away! What an incredible sight! The Earth and Moon show phases because they are between Mars and the Sun (Just like our moon, Venus and Mercury when seen from the Earth). The lower image shows the continents of North and South America as seen from Mars.
Mars has fired up our imaginations for years and will do so for years to come. This is the perfect time to go outside, look up into the night sky and admire our next-door planetary neighbor. Who will be the first to spot it coming over the horizon... will it be YOU?
To read more about Mars and Mars activities, go to: www.imagiverse.org/mars
Send your questions about Mars exploration to: Imagiverse - Ask The Expert
- 16 August 2003
17 August 2003
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