Schlagwort: NASA

Senator John Glenn during water survival training for the STS-95 mission at the Neutral Buoyancy Laboratory. On Oct. 29, 1998, space shuttle Discovery launched with Senator Glenn aboard, as he returned to space for the first time since his 1962 flight. via NASA https://ift.tt/2qh88Qp

How do galaxies grow? To help find out, the Hubble Space Telescope was deployed to image the unusual elliptical galaxy PGC 42871. How this galaxy came to be surrounded by numerous shells of stars may give clues about how it evolved. Embedded in the diffuse shells are massive globular clusters of stars — stars which analyses show were born during three different epochs. This and other data indicate that PGC 42871 has been in at least two galactic collisions, at least one of which might have been with a former spiral galaxy. The remaining spiral galaxy on the far left is at the same distance as PGC 42871 and may have been involved in some of the collisions. PGC 42871 spans about 20 thousand light years and lies about 270 million light years away toward the constellation of Centaurus. via NASA https://ift.tt/2qnNka1

Which planet is this? Earth. The featured false color picture shows how the Earth shines in ultraviolet (UV) light. The image is historic because it was taken from the surface of the Moon by humanity’s only lunar observatory. Although very little UV light is transmitted through the Earth’s atmosphere, what sunlight does make it through might cause a sunburn. The part of the Earth facing the Sun reflects much UV light, but perhaps more interesting is the side facing away from the Sun. Here bands of UV emission are the result of auroras and are caused by charged particles expelled by the Sun. Other planets showing auroras in the UV include Mars, Saturn, Jupiter, and Uranus. via NASA https://ift.tt/2qeRKzT

The best known asterism in northern skies hangs over the Canadian Rockies in this mountain and night skyscape taken last week from Banff National Park. But most remarkable is the amazing greenish airglow. With airglow visible to the eye, but not in color, the scene was captured in two exposures with a single camera, one exposure made while tracking the stars and one fixed to a tripod. Airglow emission is predominately from atmospheric oxygen atoms at extremely low densities. Commonly recorded in color by sensitive digital cameras the eerie, diffuse light is seen here in waves across the northern night. Originating at an altitude similar to aurorae, the luminous airglow is due to chemiluminescence, the production of light through chemical excitation and radiative decay. Energy for the chemical excitation is provided during daytime by the Sun’s extreme ultraviolet radiation. Unlike aurorae which are limited to high latitudes, airglow can be found around the globe. via NASA https://ift.tt/2Rko3Jg

It’s autumn in the Northern Hemisphere, which means many people living in mountainous areas are awakening to fog-filled valleys. via NASA https://ift.tt/2ELLuJP

The ghost of Cassieopeia’s ethereal glow might remind people of apparitions such as those reported by paranormal investigators. via NASA https://ift.tt/2ReS9xx