Pick Up Some Good Librations With This Stunning Moon Video

A waning gibbous moon. Rises after sunset, high in the sky after midnight, visible to the southwest after sunrise. (NASA/GSFC)


As the Moon orbits Earth, it rotates at such a rate as to keep the same face aiming our way… but not exactly the same face, as shown in this excellent video from NASA’s Goddard Space Flight Center (lovingly annotated by the Bad Astronomer himself, Dr. Phil Plait.)

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The Moon has a slight wobble to its axial rotation, and over the course of a month its orientation shifts slightly — an effect called libration. Think of it like a top or gyroscope spinning on a table; it doesn’t spin perfectly vertically, but rather sways a bit while it spins. Libration is that sway.

In addition to that movement, the Moon also moves closer to and further from the Earth over the course of a year due to its elliptical orbit. This makes it appear to change size slightly.

Except for the Moon’s phases, such effects aren’t immediately obvious from one night to the next. But when assembled into a high-resolution video using images and laser altimetry data maps from the Lunar Reconnaissance Orbiter, the monthly motions of the Moon become incredibly clear!

This video shows all the views of the Moon for the entire year of 2012.

Thanks to Phil Plait of Discover Magazine’s Bad Astronomy blog for adding the music and descriptions to the GSFC’s amazing video. What a marvelous night for a Moon dance!

See the current Moon phase and the original video on the Goddard Space Flight Center’s “Dial-A-Moon” page here.

Video: NASA/Goddard Space Flight Center Visualization Studio. Notations by Phil Plait. Music by Kevin MacLeod/incomptech.com.

Mercury Down Under

MESSENGER wide-angle camera image of Mercury's southern hemisphere.

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NASA’s MESSENGER spacecraft, about to wrap up its first full year in orbit around Mercury, captured this view of the planet’s heavily-cratered southern hemisphere on August 28, 2011. Because of its orbit, MESSENGER gets particularly good panoramic views of Mercury’s underside.

Here’s why…

MESSENGER’s orbit, established on March 18, 2011 at 00:45 UTC, is not a simple circling path around the first rock from the Sun. Instead it is highly elliptical, bringing it 124 miles (200 km) above Mercury’s north pole at its closest and more than 9,420 miles (15,193 km) from its south pole at its farthest! (See diagram below.)

The close approaches over the northern hemisphere allow MESSENGER to study the Caloris basin, Mercury’s largest surface feature and, at over 960 miles (1,550 km) across, one of the largest impact craters in the entire Solar System.

The view of Mercury’s southern hemisphere above features some notable craters as well: the relatively youthful 444-mile (715-km) -wide Rembrandt basin is seen at top right, while the smaller pit-floor crater Kipling can be discerned to its left, just below the planet’s limb.

When craters are larger than 300 km in diameter, they are referred to as basins.

During its 12 months in orbit MESSENGER will have experienced only two days on Mercury! This is because Mercury rotates very slowly on its axis, completing a full solar day (sunrise to sunrise) every 176 Earth days. (And you thought your work day seemed to last forever!)

Three perspectives of MESSENGER's orbit.

Find out more about the MESSENGER mission here.

Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington. 

A Slice of Daybreak

An orbital dawn view from the ISS on Feb. 4, 2012

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Here’s a gorgeous view from the International Space Station, taken by the Expedition 30 crew on Feb. 4, 2012 as the station passed into orbital dawn. The greens and reds of the aurora borealis shimmer above Earth’s limb beyond the Station’s solar panels as city lights shine beneath a layer of clouds.

As the ISS travels around the planet at 17,500 mph (28,163 km/h) it moves in and out of daylight, in effect experiencing dawn 16 times every day.

From that vantage point, 240 miles (386 km) above the Earth, the lights of the aurora — both northern and southern — appear below, rather than above.

See this and more images from the Space Station’s nightly flights here.

Also, here’s a time-lapse video made from photos taken by the Expedition 30 crew a few days earlier. Enjoy!

(Video courtesy of the Image Science & Analysis Laboratory, NASA Johnson Space Center.)

Far Above the World

Astronaut Bruce McCandless untethered above the Earth on Feb. 12, 1984. (NASA)
Astronaut Bruce McCandless untethered above the Earth on Feb. 12, 1984. (NASA)

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28 years ago today, NASA astronaut Bruce McCandless left the relative safety of Challenger’s payload bay and went untethered into orbit around Earth, venturing farther than anyone ever before.

The historic photo above was taken when McCandless was 320 feet from the orbiter — about the length of an American football field, or just shy of the width of the International Space Station.

The free-flying endeavor was possible because of McCandless’ nitrogen-powered jet-propelled backpack, called a Manned Maneuvering Unit (MMU). It attached to the space suit’s life-support system and was operated by hand controls, allowing untethered access to otherwise inaccessible areas of the orbiter and was also used in the deployment, service and retrieval of satellites.

Astronaut Dale Gardner using the MMU during STS-51A in Nov. 1984 to travel to the Westar VI satellite. (NASA)

The MMU used a non-contaminating nitrogen propellant that could be recharged in the orbiter. It weighed 140 kg (308 lbs) and has a built-in 35mm camera.

After the Challenger disaster, the MMU was deemed too risky and was discontinued. But for a brief period of time in the early ’80s, humans had the means for really “soaring to new heights”.

Image credits: NASA

Special Delivery, Low-Earth Orbit Style!

A Progress resupply vehicle seen on approach to the ISS on Jan. 27, 2012. (NASA)

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When you’re cruising along in low-Earth orbit, running out of supplies is not an option. Fortunately there are Progress vehicles: Russian spacecraft that carry much-needed supplies and equipment to the astronauts aboard the Space Station.

The photo above, taken by Expedition 30 crew members, shows the unmanned Progress 46 vehicle approaching the ISS on January 27, 2012.

Progress 46 carried 2,050 pounds of propellant, 110 pounds oxygen and air, 926 pounds of water and 2,778 pounds of parts and experiment hardware, for a total of 2.9 tons of food, fuel and equipment for the Expedition 30 crew.

The Progress is similar in appearance and design to Soyuz spacecraft, which serve as human transportation to and from the Space Station, but differs in that the second of the spacecraft’s three sections (as prior to launch) is a refueling module, and the third uppermost section is a cargo module.

In addition to bringing supplies to the ISS, Progress vehicles also serve as – for lack of a better term – “garbage trucks”, undocking from the Station loaded with trash and re-entering the atmosphere, during which time much of the refuse inside gets incinerated.

Progress 46 successfully docked to the Space Station at 7:09 p.m. (EST) on Jan. 27, 2012.

Image: NASA

ISS Night Flight in “Real Time”

We’ve featured wonderful time-lapse videos taken from the Space Station many times and each one is amazing to watch, but here’s something a little different: by taking photos at the rate of one per second and assembling them into a time-lapse, we can get a sense of what it’s like to orbit the planet at 240 miles up, 17,500 mph… in real time. Absolutely amazing!

Continue reading “ISS Night Flight in “Real Time””

A Space Moonrise (and the PromISSe of a New Future)

The Moon rises above (below?) Earth's limb in this view from the ISS. (ESA/NASA)

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“The moon looks the same from the ISS as it does on Earth. Only we see it rise and set again and again.”

ESA astronaut André Kuipers tweeted this message earlier today, accompanied by the wonderful photo above showing a distant Moon resting along Earth’s limb. The solar panels of the docked Soyuz TMA-03M spacecraft are seen in the foreground.

André arrived at the Space Station on December 23 along with Expedition 30 crewmates Oleg Kononeko and Don Pettit.

In addition to conducting over 45 experiments for ESA, NASA and JAXA during his five months in orbit, André’s PromISSe mission will help educate children about math, science, engineering, technology, and the benefits – and challenges – of working in space.

The program will also encourage the next generation of space explorers to stay fit with the second edition of the international fitness initiative Mission X: Train Like an Astronaut.

A medical doctor, André serves as flight engineer aboard the ISS and will be highly involved in docking procedures for the new Dragon (SpaceX) and Cygnus (Orbital Sciences) capsules as part of NASA’s next-generation commercial spaceflight program.

Read ESA’s PromISSe mission blog here, and follow André Kuipers on Twitter @astro_andre for more Expedition 30 mission updates.

A Night Flight Over the Mideast

India-Pakistan Border from ISS
India-Pakistan Border from orbit. Credit: NASA.


The cities of the Middle East and southern Asia shine bright in the night beneath the International Space Station as it passed high overhead on October 21, 2011.

This video, an animation made from dozens of still images taken by the Expedition 29 crew, was assembled by the Image Science and Analysis Laboratory at Johnson Space Center in Houston. It was uploaded to the Gateway to Astronaut Photography of Earth site on October 27.

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Some glare from the Moon (off screen to the upper left) can be seen in the Plexiglas of the ISS window. The strobe-like flashes are lightning in clouds. Airglow is also visible as a band of hazy green light surrounding the planet.

Another particularly noticeable feature visible in this video is the bright orange line of the border between India and Pakistan. Erected by the Indian government to prevent smuggling, nearly 1200 miles (1930 km) of floodlights and fences separate the two countries, creating a geopolitical feature easily visible from orbit.

The website’s description states:

The sequence of shots was taken October 21, 2011 from 19:53:26 to 20:25:24 GMT, on a pass beginning over Turkmenistan, east of the Caspian Sea to southeastern China, just northwest of Hong Kong. City lights show at the beginning of the video as the ISS travels southeastward towards the India-Pakistan borderline (click here for the Earth Observatory article to learn more about this area). Pakistan’s second largest city, Lahore, can be easily seen as the brightly lit area left of track. Immediately downtrack of Lahore is New Delhi, India’s capital city, with the Kathiawar Peninsula right of track dimly lit. Smaller cities in southern India can be seen as the pass continues southeastward through southern India, into the Bay of Bengal. Lightning storms are also present, represented by the flashing lights throughout the video. The pass ends over western Indonesia, looking left of track at the island of Sumatra.

I particularly like the way the stars shine so prominently beyond Earth’s limb, and how the moonlight illuminates the clouds… not to mention the bloom of dawn at the end. What an incredible sight this must be for the ISS crew members! I can’t imagine ever getting tired of seeing this outside the Station windows.

Watch more ISS videos here.

Video courtesy of the Image Science & Analysis Laboratory, NASA Johnson Space Center.

Fires in the Sky, Fires on the Ground

The aurora australis seen from the ISS on September 17, 2011. Credit: NASA.

 

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With all of the activity that’s been occurring on the Sun recently, the aurorae have been exceptionally bright and have created quite a show to viewers – both on Earth as well as above it!

The image above was taken over the southern Indian Ocean by astronauts aboard the International Space Station. The southern lights – a.k.a. aurora australis – glow bright green and red in the upper layers of the atmosphere, creating a dazzling aerial display. (Click here to watch a movie of this.)

Shortly after, fires can be seen on the ground as the ISS passes over Australia:

Wildfires in Australia seen from orbit. Credit: NASA.

From NASA’s Earth Observatory website:

Astronauts on the International Space Station (ISS) used a digital camera to capture several hundred photographs of the aurora australis, or “southern lights,” while passing over the Indian Ocean on September 17, 2011. You can see the flowing ribbons and rays below as the ISS passed from south of Madagascar to just north of Australia between 17:22 and 17:45 Universal Time. Solar panels and other sections of the ISS fill some of the upper right side of the photograph.

Auroras are a spectacular sign that our planet is electrically and magnetically connected to the Sun. These light shows are provoked by energy from the Sun and fueled by electrically charged particles trapped in Earth’s magnetic field, or magnetosphere. In this case, the space around Earth was stirred up by an explosion of hot, ionized gas from the Sun — a coronal mass ejection — that left the Sun on September 14, 2011.

In the second image above, and in the last frames of the movie, light from the ground replaces the light show in the sky. Wildfires and perhaps some intentionally set agricultural fires burn on the continent of Australia,with smoke plumes faintly visible in the night sky. A gold and green halo of atmospheric airglow hangs above the horizon in the distance.

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Airglow is created by particles in the upper atmosphere that have been charged by UV light from the Sun during the day releasing the energy at night as greenish-yellow visible light.

Fires on the ground, fires in the sky… the stars blazing all around, the Sun in its full glory and a never-ending view of our entire planet… what an incredible place the ISS must be to work in! Absolutely amazing!

And the skies of night were alive with light, with a throbbing, thrilling flame; Amber and rose and violet, opal and gold it came. It swept the sky like a giant scythe, it quivered back to a wedge; Argently bright, it cleft the night with a wavy golden edge.

— “The Ballad of the Northern Lights”, Robert Service

Read more on the NASA Earth Observatory.