New Explorations in the Solar System
Wilkinson, John, Teaching Science
Reductions in USA government spending have reduced NASA activity - but there are still many projects underway during 2011. Details of these projects are always interesting and provide useful contexts for the teaching of science in secondary schools. The following article provides up to date news about the continuing exploration of the solar system by NASA space probes and the Hubble Space Telescope. In particular, the article examines the latest discoveries on the asteroid Vesta, Pluto, Neptune, Titan and Jupiter.
NASA'S DAWN SPACECRAFT REACHES ASTEROID VESTA.
On July 17, 2011, NASA's Dawn spacecraft became the first probe ever to enter orbit around an object in the main asteroid belt between Mars and Jupiter.
Dawn will study the asteroid Vesta for a year before departing to meet the dwarf planet Ceres in July 2012. Observations will provide unprecedented data to help scientists understand the earliest chapter of our solar system. The data also will help pave the way for future human space missions.
Dawn took the image shown in Photo 1 during its current orbit of Vesta, travelling from the dayside to the night side. The large structure near the south pole that showed up so prominently in previous images is visible in the centre of the illuminated surface. Compared to other images, this one shows more of the surface beneath the spacecraft in the shadow of night. Vesta turns on its axis once every five hours and twenty minutes.
Dawn's study of the asteroid Vesta, marks a major scientific accomplishment and also points the way to the future destinations where people will travel in the coming years. President Obama has directed NASA to send astronauts to an asteroid by 2025, and Dawn is gathering crucial data that will inform that mission.
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The spacecraft relayed information to confirm it entered Vesta's orbit, but the precise time this milestone occurred is unknown at this time. The time of Dawn's capture depended on Vesta's mass and gravity, which only has been estimated until now. The asteroid's mass determines the strength of its gravitational pull. If Vesta is more massive, its gravity is stronger, meaning it pulled Dawn into orbit sooner. If the asteroid is less massive, its gravity is weaker and it would have taken the spacecraft longer to achieve orbit. With Dawn now in orbit, the NASA science team can take more accurate measurements of Vesta's gravity and gather more accurate timeline information.
For further information see: (http://down.ipLnoso.aov/)
NEW MOON AROUND PLUTO
The Hubble Space Telescope has discovered a new moon around Pluto. Previously known moons have the names Charon, Hydra and Nix. The new moon has the temporary name P4. Photo 2 shows P4 in two images taken about a week apart by Hubble. P4 is the smallest moon yet found around Pluto, with an estimated diameter of 13 to 34 km. By comparison, Pluto's largest moon Charon is 1,200 km across. Nix and Hydra are 32 to 113 km wide. The new moon lies between the orbits of Nix and Hydra, two satellites discovered by Hubble in 2005. P4 completes an orbit around Pluto roughly every thirty one days.
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The new moon was first seen in a photo taken with Hubble's Wide Field Camera 3 on June 28, 2011. The sighting was confirmed in follow-up Hubble observations taken July 3 and July 18. P4, Nix, and Hydra are so small and so faint, that scientists combined short and long exposures to create this image of Pluto and its entire moon system. The speckled background is camera 'noise' produced during the long exposures. The linear features are imaging artefacts. The Hubble observations will help NASA's New Horizons mission, scheduled to fly through the Pluto system in 2015.
For further information see: (http://science.noso.gov)
NEPTUNE COMPLETES ITS FIRST ORBIT AROUND THE SUN
During 2011, the planet Neptune completed its first orbit around the Sun since it was discovered in 1846. …