Some small asteroids are known to be orbiting the Sun-Earth L4 and L5 points. In fact, L4 and L5 are stable in that objects there will orbit L4 and L5 with no assistance. Some Technical Details: It is easy for an object (like a spacecraft) at one of these five points to stay in place relative to the other two bodies (e.g., the Sun and the Earth). The L1, L2, and 元 points are all in line with each other - and L4 and L5 are at the points of equilateral triangles. At Lagrange points, the gravitational pull of two large masses precisely equals the centripetal force required for a small object to move with them. Joseph-Louis Lagrange was an 18th century mathematician who found the solution to what is called the “three-body problem.” That is, is there any stable configuration, in which three bodies could orbit each other, yet stay in the same position relative to each other? As it turns out, there are five solutions to this problem - and they are called the five Lagrange points, after their discoverer. This is why the telescope is out at the second Lagrange point. To have the sunshield be effective protection (it gives the telescope the equivalent of SPF one million sunscreen) against the light and heat of the Sun/Earth/Moon, these bodies all have to be located in the same direction. The temperature difference between the hot and cold sides of the telescope is huge - you could almost boil water on the hot side, and freeze nitrogen on the cold side! The telescope itself operates at about 225 degrees below zero Celsius (minus 370 Fahrenheit). Mather said finding one with lots of water - thought to be one of the key ingredients for life - would be "really interesting." As he put it: "a wet little planet out there that might be a little bit like home.+ The temperature difference between the hot and cold sides of the telescope is huge - you could almost boil water on the hot side, and freeze nitrogen on the cold side! And that's one of our top goals - to see how stars grow, with their young planets," Mather said.Īn instrument called a spectrometer can study the atmospheres of exoplanets. "Infrared light will go around the dust grains instead of bouncing off, so we can see that with the Webb telescope. Until now, the dust in those clouds obscured the view. Mather said Webb can peer into the clouds of gas and dust where stars are being born. The goals also include observing the formation of stars and the planets around them. "We want to look at those first galaxies growing," Mather said. Its mission goals include searching for the first galaxies or luminous objects formed after the Big Bang and learning how galaxies evolved from their initial birth to the present day. We want to know: how did we get here from the Big Bang, how did that work? So, we'll look," said John Mather, Webb senior project scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "We're going to look at everything there is in the universe that we can see. After launch, it will deploy on a month-long million-mile (1.6 million km) journey to a more distant orbit than Hubble, beyond the moon. The telescope arrived in French Guiana in October after a 16-day sea journey from California through the Panama Canal to Port de Pariacabo on the Kourou River.
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