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And show  similar tilts in their rotational axes that give them strong seasonal variability; and  historic evidence of changes in climate. In this animation,

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Presentation on theme: "And show  similar tilts in their rotational axes that give them strong seasonal variability; and  historic evidence of changes in climate. In this animation,"— Presentation transcript:

1 and show  similar tilts in their rotational axes that give them strong seasonal variability; and  historic evidence of changes in climate. In this animation, we see both planets in true color first, then draped in false color, showing relative altitudes of surface features. Blues indicates low features; reds and whites indicate high features. Earth versus Mars: The two planets have striking similarities. They have …  roughly the same amount of land surface area;  relatively similar atmospheric chemistry; and  large, sustained polar caps comprising water ice;

2 Indeed, Earth’s dry valleys do look similar to those on Mars. For instance, in this animation, we plunge from space down to a remarkable scene in Antarctica, the Don Juan Pond, one of the saltiest, coldest bodies of water on Earth. In the first scene the camera slides down the valley slope and stops above the actual pond of sub-freezing water at the base. We see the crinkled folds and dug outrivulets and gullies eroded into the landscape. They serve as the signs of surface erosion and are analogous to the kinds of tell-tale signatures that Mars experts want to study more thoroughly for the signs of a wetter Martian past. crinkled folds and dug out rivulets and gullies eroded into the landscape. They serve as the signs of surface erosion and are analogous to the kinds of tell-tale signatures that Mars experts want to study more thoroughly for the signs of a wetter Martian past.

3 Evidence of Surface Water: Earth Deltas, Martian Deltas These images compares how evidence of water appears on Earth, offering clues as to where we might look for itspresence on Mars.  The first two sequences here depict (a) the mouth of the Colorado River in the Mexican Baja, and (b) the Lena River Delta in Russia. Data for these scenes come from the Landsat 7 spacecraft.  As for Mars, we see here the so-called “Distributary Fan” located northeast of Holden Crater. As seen from Martian orbit by the Mars Orbiting Camera flying on the Mars Global Surveyor spacecraft, this dramatic visualization shows us where liquid water likely flowed across the Martian surface sometime in the planet’s past.

4 On Mars, scientists are looking for signs of life in the planet’s past. Unlike the Earth, Mars is no longer a hospitable place for life, because it is generally bathed in a lethal dose of cosmic radiation, not to mention high energy the particles blown by solar wind. It is also cold and dry, with no ready availability of water. The Earth bursts with life, with carbon as life’s proxy, because life as we know it basically implies transactions in carbohydrates (CH 2 O). A thorough understanding of the Earth’s carbon cycle is therefore vital to a search for life elsewhere in the universe. The undulating colors in these scenes come from NASA’s SeaWiFS instrument. They show the cycle of life as it ebbs and flows through the carbon cycle. The pulse of this carbon uptake is reflected in the oscillation of chlorophyll concentrations, depicted by this intuitive false color representation.NASA’s SeaWiFS

5 Magnetic Signatures: Mars does not have the same kind of magnetic field as Earth. But evidence collected by the Mars Global Surveyor (MGS) indicates that the planet may have once had a global magnetic field, generated by an internal dynamo. Evidence suggests that the planet’s magnetic field reversed direction, or flipped, several times in its early days as conditions in the mantle and core of the planet changed. But that dynamo faded, leaving only faint traces of its magnetic past locked in the Martian crust.

6 Some Basic Facts about Earth Ave. Solar Distance: 149,600,000 km (1AU) Diameter: km Rotational Period (one day): 23 hours, 57 minutes Mean Surface Temp: 14_ C Orbital Period (one year): Earth days Moons: 1 (Luna) Gravity: 9.78 (m/s2) Earth Some Basic Facts about Mars  Ave. Solar Distance: 227,940,000 km (1.52 AU)  Diameter: 6,794 km  Rotational Period (one day): hours Mean Surface Temp: -63_ C Orbital Period (one year): days Moons: 2 (Phobos and Demios) Gravity: 38% Earth

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