Posts tagged earth

Posted 12 months ago

Crescent Neptune and Triton 
Image Credit: Voyager 2, NASA

Explanation: Gliding silently through the outer Solar System, the Voyager 2 spacecraft camera captured Neptune and Triton together in crescent phase in 1989. The elegant picture of the gas giant planet and its cloudy moon was taken from behind just after closest approach. It could not have been taken from Earth because Neptune never shows a crescent phase to sunward Earth. The unusual vantage point also robs Neptune of its familiar blue hue, as sunlight seen from here is scattered forward, and so is reddened like thesetting SunNeptune is smaller but more massive than Uranus, has several dark rings, and emits more light than it receives from the Sun.

Posted 12 months ago

Sun with Solar Flare 
Image Credit: NASA Solar Dynamics Observatory

Explanation: This week the Sun gave up its strongest solar flare so far in 2013, accompanied by a coronal mass ejection (CME) headed toward planet Earth. A false-color composite image in extreme ultraviolet light from the Solar Dynamics Observatory captures the moment, recorded on April 11 at 0711 UTC. The flash, a moderate, M6.5 class flare erupting from active region AR 11719, is near the center of the solar disk. Other active regions, areas of intense magnetic fields seen as sunspot groups in visible light, mottle the surface as the solar maximum approaches. Loops and arcs of glowing plasma trace the active regions’ magnetic field lines. A massive cloud of energetic, charged particles, the CME will impact the Earth’s magnetosphere by this weekend and skywatchers should be on the alert for auroral displays.

Posted 12 months ago

Yuri’s Planet 
Image Credit: ISS Expedition 30NASA

Explanation: On another April 12th, in 1961, Soviet cosmonaut Yuri Alexseyevich Gagarin became the first human to see planet Earth from space. Commenting on his view from orbit he reported, “The sky is very dark; the Earth is bluish. Everything is seen very clearly”. On yet another April 12th, in 1981 NASA launched the first space shuttle. To celebrate in 2013, consider this image from the orbiting International Space Station, a stunning view of the planet at night from low Earth orbit. Constellations of lights connecting the densely populated cities along the Atlantic east coast of the United States are framed by two Russian spacecraft docked at the space station. Easy to recognize cities include New York City and Long Island at the right. From there, track toward the left for Philadelphia, Baltimore, and then Washington DC near picture center.

Posted 1 year ago

Earth at Twilight 
Image Credit: ISS Expedition 2 CrewGateway to Astronaut Photography of EarthNASA

Explanation: No sudden, sharp boundary marks the passage of day into night in this gorgeous view of ocean and clouds over our fair planet Earth. Instead, the shadow line or terminator is diffuse and shows the gradual transition to darkness we experience as twilight. With the Sun illuminating the scene from the right, the cloud tops reflect gently reddened sunlight filtered through the dusty troposphere, the lowest layer of the planet’s nurturing atmosphere. A clear high altitude layer, visible along the dayside’s upper edge,scatters blue sunlight and fades into the blackness of space. This picture actually is a single digital photograph taken in June of 2001 from the International Space Station orbiting at an altitude of 211 nautical miles.

Posted 1 year ago

Flying Over the Earth at Night 
Video Credit: Gateway to Astronaut PhotographyNASA ; Compilation: David Peterson (YouTube); 
Music: Freedom Fighters (Two Steps from Hell)

Explanation: Many wonders are visible when flying over the Earth at night. A compilation of such visual spectacles was captured recently from theInternational Space Station (ISS) and set to rousing music. Passing below are white cloudsorange city lightslightning flashes in thunderstorms, and darkblue seas. On the horizon is the golden haze of Earth’s thin atmosphere, frequently decorated by dancing auroras as the video progresses. The green parts of auroras typically remain below the space station, but the station flies right through the red and purple auroral peaks. Solar panels of the ISS are seen around the frame edges. The ominous wave of approaching brightness at the end of each sequence is just the dawn of the sunlit half of Earth, a dawn that occursevery 90 minutes.

Posted 1 year ago

GRAIL Maps the Moon’s Gravity 
Image Credit & Copyright: NASAJPL-CaltechMITGSFCSVC

Explanation: How did the Moon form? To help find out, NASA launched the twin Gravity Recovery and Interior Laboratory(GRAIL) satellites in 2011 to orbit and map the Moon’s surface gravity in unprecedented detailPictured above is a resultingGRAIL gravity map, with regions of slightly lighter gravity shown in blue and regions of slightly stronger gravity shown in red. Analysis of GRAIL data indicates that the moon has an unexpectedly shallow crust than runs about 40 kilometers deep, and an overall composition similar to the Earth. Although other surprising structures have been discovered that will continue to be investigated, the results generally bolster the hypothesis that the Moon formed mostly from Earth material following a tremendous collision in the early years of our Solar System, about 4.5 billion years ago. After completing their mission and running low on fuel, the two GRAIL satellites, Ebb and Flow, were crashed into a lunar crater at about 6,000 kilometer per hour.

Posted 1 year ago

Comet PANSTARRS Just After Sunset 
Image Credit & Copyright: Chris Cook

Explanation: Have you seen the comet? As Comet PANSTARRS fades, careful observers — even with unaided eyes — should still be able to find the shedding ice ball on the western horizon just after sunset. Pictured above, Comet PANSTARRS (C/2011 L4) was pointed out from a hilltop last week on First Encounter Beach in MassachusettsUSA. The comet was discovered by — and is named for — the Pan-STARRS astronomical sky survey that discovered it. As the comet now recedes from both the Earth and the Sun, it will remain visible further into the night, although binoculars or a small telescope will soon to be needed to find it.

Posted 1 year ago

CME, Comet and Planet Earth 
Image Credit: NRL / SECCHI / STEREO / NASA 
Processing - Karl Battams (NRL and @SungrazerComets)

Explanation: After appearing in a popular photo opportunity with a young crescent Moon near sunset, naked-eye Comet PanSTARRScontinues to rise in northern hemisphere skies. But this remarkable interplanetary perspective from March 13, finds the comet posing with our fair planet itself - as seen from the STEREO Behind spacecraft. Following in Earth’s orbit, the spacecraft is nearly opposite the Sun and looks back toward the comet and Earth, with the Sun just off the left side of the frame. At the left an enormous coronal mass ejection (CME) is erupting from a solar active region. Of course, CME, comet, and planet Earth are all at different distances from the spacecraft. (The comet is closest.) The processed digital image is the difference between two consecutive frames from the spacecraft’s SECCHI Heliospheric Imager, causing the strong shadowing effect for objects that move between frames. Objects that are too bright create the sharp vertical lines. The processing reveals complicated feather-like structures in Comet PanSTARRS’s extensive dust tail.

Posted 1 year ago

Miass River Sunrise 
Image Credit & CopyrightMarat Ahmetvaleev

Explanation: Each day on planet Earth can have a serene beginning at sunrise as the sky gently grows bright over a golden eastern horizon. This sunrise panorama seems to show such a moment on the winter morning of February 15. In the mist, a calm, mirror-like stretch of the Miass River flows through the foreground along a frosty landscape near Chelyabinsk, Russia. But the long cloud wafting through the blue sky above is the evolving persistent train of the Chelyabinsk Meteor. The vapor trail was left by the space rock that exploded over the city only 18 minutes earlier, causing extensive damage and injuring over 1,000 people. A well-documented event, the numerous webcam and dashcam video captures from the region soon contributed to a reconstruction of the meteor’s trajectory and an initial orbit determination.Preliminary findings indicate the parent meteoriod belonged to the Apollo class of Earth crossing asteroids.

Posted 1 year ago

Snow Moon for a Snowy Planet 
Image Credit & CopyrightGöran Strand

Explanation: The alarmingly tall inhabitants of this small, snowy planet cast long shadows in bright moonlight. Of course, the snowy planet is actually planet Earth and the wide-angle mosaic, shown as a little planet projection, was recorded on February 25 during the long northern night of the Full Snow Moon. The second brightest celestial beacon is Jupiter, on the right above the little planet’s horizon. Lights near Östersund, Sweden glow along the horizon, surrounding the snow covered lake Storsjön. The photographer reports that the journey out onto the frozen lake by sled to capture the evocativeFull Snow Moon scene was accompanied by ice sounds, biting cold, and a moonlit mist.