It looks like a big space diamond — but with craters. It’s 162173 Ryugu (Dragon’s Castle), and Japan‘s robotic Hayabusa2 mission is now arriving at this near-Earth asteroid. Ambitious Hayabusa2 is carrying an armada of separable probes, including two impactors, four small close-proximity hoverers, three small surface hoppers, and the Mobile Asteroid Surface Scout (MASCOT) which will land, study, and move around on Ryugu’s surface. Most of these are equipped with cameras. Moreover, Hayabusa2 itself is scheduled to collect surface samples and return these samples to Earth for a detailed analysis near the end of 2020. Previously, what was known about asteroid Ryugu was its orbit, that it spans about one kilometer, and that it has a dark surface that reflects unusual colors. Studying Ryugu could tell humanity not only about Ryugu’s surface and interior, but about what materials were available in the early Solar System for the development of life. Pictured, a series of approach images shows features suggestive of large boulders and craters.
Why would the shadow of a space shuttle launch plume point toward the Moon? In early 2001 during a launch of Atlantis, the Sun, Earth, Moon, and rocket were all properly aligned for this photogenic coincidence. First, for the space shuttle‘s plume to cast a long shadow, the time of day must be either near sunrise or sunset. Only then will the shadow be its longest and extend all the way to the horizon. Finally, during a Full Moon, the Sun and Moon are on opposite sides of the sky. Just after sunset, for example, the Sun is slightly below the horizon, and, in the other direction, the Moon is slightly above the horizon. Therefore, as Atlantis blasted off, just after sunset, its shadow projected away from the Sun toward the opposite horizon, where the Full Moon happened to be.
A small crystal ball seems to hold a whole galaxy in this creative snapshot. Of course, the galaxy is our own Milky Way. Its luminous central bulge marked by rifts of interstellar dust spans thousands of light-years. On this long southern hemisphere night it filled dark Chilean skies over Paranal Observatory. The single exposure image did not require a Very Large Telescope, though. Experiments with a digital camera on a tripod and crystal ball perched on a handrail outside the Paranal Residencia produced the evocative, cosmic marble portrait of our home galaxy.
Skies after the near-solstice sunset on June 17 are reflected in this calm lake. The tranquil twilight scene was captured near Bashaw, Alberta, Canada, northern planet Earth. Usually spotted at high latitudes in summer months, night shining or noctilucent clouds hang just above the horizon, transfusing light into a darker sky. Near the edge of space, the icy apparitions are condensations on meteoric dust or volcanic ash still in sunlight at extreme altitudes. Also near the edge of space on this short northern night, solar activity triggered the lovely apparition of aurora borealis or northern lights.
Newborn stars are forming in the Eagle Nebula. Gravitationally contracting in pillars of dense gas and dust, the intense radiation of these newly-formed bright stars is causing surrounding material to boil away. This image, taken with the Hubble Space Telescope in near infrared light, allows the viewer to see through much of the thick dust that makes the pillars opaque in visible light. The giant structures are light years in length and dubbed informally the Pillars of Creation. Associated with the open star cluster M16, the Eagle Nebula lies about 6,500 light years away. The Eagle Nebula is an easy target for small telescopes in a nebula-rich part of the sky toward the split constellation Serpens Cauda (the tail of the snake).
Sometimes the Sun’s surface becomes a whirlwind of activity. Pictured is a time-lapse video of the Sun‘s surface taken over a two hour period in early May, run both forwards and backwards. The Sun’s surface was blocked out so that details over the edge could be imaged in greater detail. Hot plasma is seen swirling over the solar limb in an ongoing battle between changing magnetic fields and constant gravity. The featured prominence rises about one Earth-diameter over the Sun’s surface. Energetic events like this are becoming less common as the Sun nears a minimum in its 11-year activity cycle.
What’s happened to Mars? In 2001, Mars underwent a tremendous planet-wide dust storm — one of the largest ever recorded from Earth. To show the extent, these two Hubble Space Telescope storm watch images from late June and early September (2001) offer dramatically contrasting views of the martian surface. At left, the onset of smaller “seed” storms can be seen near the Hellas basin (lower right edge of Mars) and the northern polar cap. A similar surface view at right, taken over two months later, shows the fully developed extent of the obscuring global storm. Although this storm eventually waned, in recent days a new large dust storm has been taking hold of the red planet.