Scientist send mars rs7 .00/per k.m our indian priminister says media What is the Distance from Earth to Mars? by FRASER CAIN on DECEMBER 5, 2013 This article was originally published on Aug 10, 2012. We’ve updated it and added this cool new video! Sending spacecraft to Mars is all about precision. It’s about blasting off from Earth with a controlled explosion, launching a robot into space in the direction of the Red Planet, navigating the intervening distance between our two planets, and landing with incredible precision. This intricate and complicated maneuver means knowing the exact distance from Earth to Mars. And unfortunately, this distance is always changing. The first person to ever calculate the distance to Mars was the astronomer Giovanni Cassini, famous for his observations of Saturn. Giovanni made observations of Mars in 1672 from Paris, while his colleague, Jean Richer made the same observation from Cayenne, French Guiana. They used the parallax method to calculate the distance to Mars with surprising accuracy. However, astronomers now calculate the distance to objects in the Solar System using the speed of light. They measure the time it takes for signals to reach spacecraft orbiting other planets. They can bounce powerful radar off planets and measure the time it takes for signals to return. This allows them to measure the distance to planets, like Mars, with incredible accuracy. How Far is Mars From Earth? So, how far away is Mars? The answer to that question changes from moment to moment because Earth and Mars are orbiting the Sun. Both Earth and Mars are following elliptical orbits around the Sun, like two cars travelling at different speeds on two different racetracks. Sometimes the planets are close together, and other times they’re on opposite sides of the Sun. And although they get close and far apart, those points depend on where the planets are on their particular orbits. So, the Earth Mars distance is changing from minute to minute. A Quick Explainer on Orbital Mechanics The planets don’t follow circular orbits around the Sun, they’re actually travelling in ellipses. Sometimes they’re at the closest point to the Sun (called perihelion), and other times they’re at the furthest point from the Sun (known as aphelion). To get the closest point between Earth and Mars, you need to imagine a situation where Earth and Mars are located on the same side of the Sun. Furthermore, you want a situation where Earth is at aphelion, at its most distant point from the Sun, and Mars is at perihelion, the closest point to the Sun. When Earth and Mars are closest When Earth and Mars reach their closest point, this is known as opposition. It’s the time that Mars appears as a bright red star of the sky; one of the brightest objects, rivalling the brightness of Venus or Jupiter. There’s no question Mars is bright and close, you can see it with your own eyes. And theoretically at this point, Mars and Earth will be only 54.6 million kilometers from each other. But here’s the thing, this is just theoretical, since the two planets haven’t been this close to one another in recorded history. The last known closest approach was back in 2003, when Earth and Mars were only 56 million kilometers apart. And this was the closest they’d been in 50,000 years. Need that in miles? The closest possible distance from Earth to Mars in miles is 33.9 million miles.
Posted on: Mon, 29 Sep 2014 14:07:57 +0000
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