Add To Favorites
Goodbye Earth. Earlier this month, ESA's interplanetary Rosetta spacecraft zoomed past the Earth on its way back across the Solar System. Pictured above, Earth showed a bright crescent phase featuring the South Pole to the passing rocket ship. Launched from Earth in 2004, Rosetta used the gravity of the Earth to help propel it out past Mars and toward a 2014 rendezvous with Comet Churyumov-Gerasimenko. Last year, the robot spacecraft passed asteroid 2867 Steins, and next year it is scheduled to pass enigmatic asteroid 21 Lutetia. If all goes well, Rosetta will release a probe that will land on the 15-km diameter comet in 2014.
2009-11-23 ESA (MPS for OSIRIS Team), MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA
Add To Favorites
This panorama of the cratered lunar surface was constructed from images returned by the US Surveyor 6 lander. Surveyor 6 was not the first spacecraft to accomplish a soft landing on the Moon ... but it was the first to land and then lift off again! After the spacecraft touched down near the center of the Moon's nearside in November of 1967, NASA controllers commanded it to hop. Briefly firing its rocket engine and lifting itself some 4 meters above the surface, the Surveyor moved about 2.5 meters to one side before setting down again. The hopping success of Surveyor 6 essentially marked the completion of the Surveyor series main mission - to determine if the lunar terrain was safe for the planned Apollo landings.
2005-11-12
Add To Favorites
Just before the Sun blacks out, something strange occurs. As the Moon moves to completely cover the Sun in a total solar eclipse, beads of bright sunlight stream around the edge of the Moon. This effect, known as Baily's beads, is named after Francis Baily who called attention to the phenomenon in 1836. Although, the number and brightness of Baily's beads used to be unpredictable, today the Moon is so well mapped that general features regarding Baily's beads are expected. When a single bead dominates, it is called the diamond ring effect, and is typically seen just before totality. Pictured above, a series of images recorded Baily's beads at times surrounding the recent total solar eclipse visible from Novosibirsk, Russia. The complete series can be seen by scrolling right. At the end of totality, as the Sun again emerges from behind the moon, Baily's beads may again be visible -- but now on the other side of the Moon.
2008-08-18 Leonid Durman
Add To Favorites
A recent informal poll found that astronomers don't yet have a good collective noun for a group of black holes, but they need one. The red circles in this Chandra Observatory X-ray image identify a group of a dozen black holes that are members of binary star systems. With 5 to 30 times the mass of the Sun, the black hole binaries are swarming within about 3 light-years of the center of our galaxy where the supermassive black hole identified as Sagittarius A* (Sgr A*) resides. Yellow circles indicate X-ray sources that are likely less massive neutron stars or white dwarf stars in binary star systems. Alone, black holes would be invisible, but as part of a binary star system they accrete material from their normal companion star and generate X-rays. At the distance of the galactic center Chandra can detect only the brighter of these black hole binary systems as point-like sources of X-rays, hinting that many fainter X-ray emitting black hole binaries should exist there, as yet undetected.
2018-05-12
Add To Favorites
Barred spiral galaxy NGC 2903 is only some 20 million light-years distant. Popular among amateur astronomers, it shines in the northern spring constellation Leo, near the top of the lion's head. That part of the constellation is sometimes seen as a reversed question mark or sickle. One of the brighter galaxies visible from the northern hemisphere, NGC 2903 is surprisingly missing from Charles Messier's catalog of lustrous celestial sights. This colorful image from a small ground-based telescope shows off the galaxy's gorgeous spiral arms traced by young, blue star clusters and pinkish star forming regions. Included are intriguing details of NGC 2903's bright core, a remarkable mix of old and young clusters with immense dust and gas clouds. In fact, NGC 2903 exhibits an exceptional rate of star formation activity near its center, also bright in radio, infrared, ultraviolet, and x-ray bands. Just a little smaller than our own Milky Way, NGC 2903 is about 80,000 light-years across.
2015-04-10 Tony Hallas
Add To Favorites
What is that dark streak below Prometheus? Although it may look like a shadow or a trail blazed by sweeping up material, computer simulations indicate that the dark streak is better understood as an empty path pulled away by the gravity of Saturn's small moon. The particles don't follow Prometheus so much as glide sideways past where Prometheus used to be. One dark streamer is created during each pass of Prometheus through the F-ring that it shepherds. The streamers were unpredicted and first discovered in 2004 on high resolution images taken by the robotic Cassini spacecraft orbiting Saturn. Close inspection of the surface of Prometheus itself in the above image shows interesting structure and craters. The Cassini spacecraft arrived at Saturn in 2004 and, as it continues to function well, is now expected to continue to send back data and images from the distant ringed world until 2017.
2010-10-19
Add To Favorites
Gripped by an astronomical spring fever, it's once again time for many amateur stargazers to embark on a Messier Marathon! The Vernal Equinox occurs March 20, marking the first day of Spring for the Northern Hemisphere. It also marks a favorable celestial situation for potentially viewing all the objects in 18th century French astronomer Charles Messier's catalog in one glorious dusk to dawn observing run. This year a bright full moon will interfere with dark skies near the actual equinox, so good nights near new moon for weekend marathoners are March 11/12 and April 1/2. (As an added bonus all the planets in the solar system can be viewed on these dates.) Astronomer Paul Gitto has created this masterful Messier Marathon grid with 11 rows and 10 columns of Messier catalog objects. In numerical order, the grid begins with M1, the Crab Nebula, at upper left and ends with M110, a small elliptical galaxy in Andromeda (lower right). Gitto's images were made with a digital camera and a 10-inch diameter reflecting telescope.
2000-03-11 P. Gitto
Add To Favorites
On January 21, light from the Moon near first quarter illuminated the foreground in this snowy mountain and night scene. Known as The Lions, the striking pair of mountain peaks are north of Vancouver, British Colombia, Canada, North America, planet Earth. Poised above the twin summits, left of Deneb alpha star of the constellation Cygnus, are emission regions NGC 7000 and IC 5070. Part of a large star forming complex about 1,500 light-years from Vancouver, they shine with the characteristic red glow of atomic hydrogen gas. Outlines of the bright emission regions suggest their popular names, The North America Nebula and The Pelican Nebula. The well-planned, deep nightscape is a composite of consecutive exposures made with a modified digital camera and telephoto lens. Foreground exposures were made with camera fixed to a tripod, background exposures were made tracking the sky. The result preserves sharp natural detail and reveals a range of brightness and color that your eye can't quite see on its own.
2021-01-29 Liron Gertsman
Add To Favorites
Where are the Milky Way's gas clouds and where are they going? Stars form in gas clouds, and the motion of gas clouds tell us about the size and rotation speed of our own Milky Way Galaxy. But gas clouds are hard to detect - they are composed mostly of nearly invisible molecular hydrogen and helium. Fortunately, at least small amounts of heavier gases co-exist, one of them being carbon monoxide (CO), which is relatively easy to detect at radio wavelengths. Therefore, over the past decade, a team of astronomers have carefully mapped out the molecular sky to unprecedented clarity - to about four times previous resolution and about eight times previous sensitivity. The resulting map is shown above, rescaled and in false color, with dark blue being relatively low emission. The band of our Milky Way Galaxy spans the middle. The data have not only helped our understanding of the Galaxy, but highlight a few mysteries too. For example: what causes the rapid speed of the gas near the Galactic Center?
1997-04-30
Add To Favorites
Here's a switch: the above picture is of the Earth taken from a lunar observatory! This false color picture shows how the Earth glows in ultraviolet (UV) light. UV light is so blue humans can't see it. Very little UV light is transmitted through the Earth's atmosphere but what sunlight does make it through can cause a sunburn. The Far UV Camera / Spectrograph deployed and left on the Moon by the crew of Apollo 16 took the above picture. 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 also apparent. These bands are the result of aurorae and are caused by charged particles expelled by the Sun.
2000-07-01