麻豆淫院

(麻豆淫院) -- 贰厂础鈥檚 Venus Express and Proba-2 space missions, along with the international SOHO, Hinode, and Hubble spacecraft, are preparing to monitor Venus and the Sun during the transit of Earth鈥檚 sister planet during 5-6 June.

贰厂础鈥檚 Venus Express is the only spacecraft orbiting Venus at the moment and while the transit is being watched from Earth, it too will use light from the Sun to study the planet鈥檚 atmosphere.

As sunlight filters through the atmosphere it reveals the concentration of different gas molecules at different altitudes.

This technique is also used to probe the atmospheres of planets outside our Solar System 鈥� exoplanets 鈥� to determine their potential habitability.

Simultaneous measurements are planned during the transit from ground-based observatories around the world to compare with the Venus Express results.  

Exoplanet scientists can then test their techniques for looking at the characteristics of rocky Earth-sized planets.

Because Venus Express is in orbit around the planet, it will not notice any difference while the transit is being observed from Earth. But the spacecraft will be watching the Sun setting through the atmosphere of Venus, and its data will be compared to measurements made at the Earth at the same time.

These will include data from 贰厂础鈥檚 Proba-2 microsatellite and Japan鈥檚 Hinode solar satellite, which will have ringside seats in low-Earth orbit to watch as Venus passes in front of the Sun.

鈥淧roba-2 is expected to see a dip in the solar brightness as soon as the thick atmosphere of Venus makes first contact with the solar disc, which is an important measurement for exoplanet scientists,鈥� says Joe Zender, 贰厂础鈥檚 Proba-2 mission manager.

There is also the possibility that if Venus passes exactly in front of an active region on the Sun we can obtain information about the energy emitted by that region.

鈥淭his is important for space weather studies that help us to understand the Sun and its influence on Earth.鈥�

Hinode will be watching the transit in visible, X-ray, and ultraviolet wavelengths to study phenomena such as the 鈥檅lack drop effect鈥� 鈥� the small black teardrop shape that appears to connect Venus to the limb of the Sun just after it has fully entered the solar disc and again later, when it begins to leave the disc.

It will also observe the aureole, an arc of light seen around the planet鈥檚 disc during the first and last minutes of the transit.

鈥淭he most spectacular images and movies should come from Hinode鈥檚 Solar Optical Telescope, which has by far the highest resolution of any solar instrument in space,鈥� says Bernhard Fleck, 贰厂础鈥檚 Hinode and SOHO project scientist.

鈥淯nfortunately, SOHO will not be well placed to observe the transit. However, it has one thing that no other spacecraft can provide: views of Venus as it approaches the Sun days before the actual transit, and then moves away from the Sun for several days after the transit.鈥�

Meanwhile, NASA/贰厂础鈥檚 Hubble Space Telescope will use the Moon as a giant mirror to capture diffuse, reflected sunlight: a small fraction of that light will have passed through the atmosphere of Venus en-route to the Moon.

This will test techniques aimed at measuring the atmospheres of Earth-sized rocky exoplanets that could potentially reveal traces of life on planets outside our Solar System.