No, the car was not in danger of being vacuumed into space by the big sky vortex. For one reason, the vortex was really an aurora, and since auroras are created by particles striking the Earth from space, they do not create a vacuum. This rapidly developing auroral display was caused by a Coronal Mass Ejection from the Sun that passed by the Earth closely enough to cause a ripple in Earth's magnetosphere. The upper red parts of the aurora occur over 250 kilometers high with its red glow created by atmospheric atomic oxygen directly energized by incoming particles. The lower green parts of the aurora occur over 100 kilometers high with its green glow created by atmospheric atomic oxygen energized indirectly by collisions with first-energized molecular nitrogen. Below 100 kilometers, there is little atomic oxygen, which is why auroras end abruptly. The concentric cylinders depict a dramatic auroral corona as seen from the side. The featured image was created from a single 3-second exposure taken in mid-March over Lake Myvatn in Iceland. April is: Global Astronomy Month
Start with the constellation of Orion. Near Orion's belt is a fuzzy area known as the Great Nebula of Orion or M42. In this nebula is a bright star cluster known as the Trapezium, shown above. New stellar systems are forming there in gigantic globs of gas and dust known as Proplyds. Looking closely at the above picture also reveals that gas and dust surrounding some of the dimmer stars appears to form structures that point away from the brighter stars. The above false color image was made by combining several exposures from the orbiting Hubble Space Telescope.
Last week, a small asteroid approached unusually close to the Earth. Asteroid 2004 FH posed no danger, but became bright enough to see with binoculars. Passing only 7 Earth radii away, this asteroid pass was the closest yet that was previously predicted, although it was discovered only two days before. Pictured above, the 30-meter sized 2004 FH was imaged from Switzerland crossing the sky on March 18, near its closest approach. The asteroid, centered in the above time-lapse movie covering about 30 minutes, changes in brightness as it tumbles by. An asteroid this size passes this close to Earth about every two years. Were 2004 FH to have struck the Earth, it would have likely burned up in the atmosphere. Large impact features on the Earth are testaments, however, to larger asteroids and comets that actually impacted the Earth in the distant past. Astronomers continue to discover, track, and study potentially hazardous asteroids with a goal of making planet Earth a safer place.
Beginning with a full view of beautiful spiral galaxy M81, follow the insets (left, bottom, then right) to zoom in on a real survivor. Seen at the center of the final field on the right is a star recently identified as the survivor of a cosmic cataclysm -- the supernova explosion of its companion star. Light from the cosmic blast, likely triggered by the core collapse of a star initially more than 10 times as massive as the Sun, first reached Earth over 10 years ago and was cataloged as supernova SN 1993J. Though the supernova itself is no longer visible, light-echoes from dust in the region can still be seen near the companion, the first known survivor of a supernova in a binary star system. Astronomers believe that a substantial transfer of material to the surviving companion star during the last few hundred years before the stellar explosion can explain peculiarities seen in this supernova. After supernova SN 1987A in the Large Magellanic Cloud, SN 1993J in nearby M81 is the brightest supernova seen in modern times.
What's happening with these clouds? While it may seem that these long and thin clouds are pointing toward the top of a hill, and that maybe a world-famous observatory is located there, only part of that is true. In terms of clouds, the formation is a chance superposition of impressively periodic undulating air currents in Earth's lower atmosphere. Undulatus, a type of Asperitas cloud, form at the peaks where the air is cool enough to cause the condensation of opaque water droplets. The wide-angle nature of the panorama creates the illusion that the clouds converge over the hill. In terms of land, there really is a world-famous observatory at the top of that peak: the Carnegie Science's Las Campanas Observatory in the Atacama Desert of Chile. The two telescope domes visible are the 6.5-meter Magellan Telescopes. The featured coincidental vista was a surprise but was captured by the phone of a quick-thinking photographer in late September. Your Sky Surprise: What picture did APOD feature on your birthday? (post 1995)
rlier this month, a 2.5-meter diameter infrared telescope was permanently assigned a window seat, looking through this opening in the fuselage of a historic Boeing 747 aircraft. The telescope mirror, about the size of the Hubble Space Telescope mirror, is protected by a red covering. Known as the Stratospheric Observatory For Infrared Astronomy (SOFIA), the airborne observatory is intended to fly at altitudes up to 45,000 feet - above more than 99% of the atmospheric water vapor. Water vapor strongly absorbs infrared light, so at that altitude SOFIA will be able to acquire infrared images not possible for even the largest ground-based telescopes. SOFIA's unique capabilities will include the ability to trace complex molecules in the cosmic environments surrounding star birth and death and the formation of new solar systems. The SOFIA aircraft was operated by Pan American World Airways and was originally christened the "Clipper Lindbergh". The airborne observatory was designed with an on board console for teachers and other educators to participate in research flights.
Some moons wouldn't survive the collision. Tethys, one of Saturn's larger moons at about 1000 kilometers in diameter, survived the collision, but sports today the expansive impact crater Odysseus. Sometimes called the Great Basin, Odysseus occurs on the leading hemisphere of Tethys and shows its great age by the relative amount of smaller craters that occur inside its towering walls. The density of Tethys is similar to water-ice. The above digitally enhanced image was captured late last year by the robot Cassini spacecraft in orbit around Saturn as it swooped past the giant ice ball.
Grand design spiral galaxy Messier 99 looks majestic on a truly cosmic scale. This recently processed full galaxy portrait stretches over 70,000 light-years across M99. The sharp view is a combination of ultraviolet, visible, and infrared image data from the Hubble Space Telescope. About 50 million light-years distant toward the well-groomed constellation Coma Bernices, the face-on spiral is a member of the nearby Virgo Galaxy Cluster. Also cataloged as NGC 4254, a close encounter with another Virgo cluster member has likely influenced the shape of its well-defined, blue spiral arms.
Dust pillars are like interstellar mountains. They survive because they are more dense than their surroundings, but they are being slowly eroded away by a hostile environment. Visible in the above picture is the end of a huge gas and dust pillar in the Trifid Nebula, punctuated by a smaller pillar pointing up and an unusual jet pointing to the left. The pink dots are newly formed low-mass stars. A star near the small pillar's end is slowly being stripped of its accreting gas by radiation from a tremendously brighter star situated off the above picture to the upper right. The jet extends nearly a light-year and would not be visible without external illumination. As gas and dust evaporate from the pillars, the hidden stellar source of this jet will likely be uncovered, possibly over the next 20,000 years. APOD presents: Astronomy Pictures of the Year for 2007
In this Hubble Space Telescope image the bright, spiky stars lie in the foreground toward the heroic northern constellation Perseus and well within our own Milky Way galaxy. In sharp focus beyond is UGC 2885, a giant spiral galaxy about 232 million light-years distant. Some 800,000 light-years across compared to the Milky Way's diameter of 100,000 light-years or so, it has around 1 trillion stars. That's about 10 times as many stars as the Milky Way. Part of an investigation to understand how galaxies can grow to such enormous sizes, UGC 2885 was also part of An Interesting Voyage and American astronomer Vera Rubin's pioneering study of the rotation of spiral galaxies. Her work was the first to convincingly demonstrate the dominating presence of dark matter in our universe. A new U.S. coin has been issued to honor Vera Rubin, while the Vera C. Rubin Observatory is scheduled to unveil images from its first look at the cosmos on June 23.
Why are some hills on Mars so layered? The answer is still under investigation. Clearly, dark windblown sand surrounds outcropping of light sedimentary rock across the floor of crater Arabia Terra. The light rock clearly appears structured into many layers, the lowest of which is likely very old. Although the dark sand forms dunes, rippled dunes of lighter colored sand are easier to see surrounding the stepped mesas. Blown sand possibly itself eroded once-larger mesas into the layered hills. Most of the layered shelves are wide enough to drive a truck around. The above image, showing an area about 3 kilometers across, was taken in 2003 October by the now defunct Mars Global Surveyor spacecraft orbiting Mars.
Just after the Moon set but before the Sun rose in the early morning hours of August 12, meteors pelted the Earth from the direction of the constellation Perseus, while ions pelted the Earth from the Sun. The meteors were expected as sub-sand grains long left behind by Comet Swift-Tuttle annually create the Perseids Meteor Shower. The aurorae were unexpected, however, as electrons, protons, and heavier ions raced out from a large Coronal Mass Ejection that had occurred just days before on the Sun. In the foreground is Hahn's Peak, an extinct volcano in Colorado, USA.