On the afternoon of Friday, May 31, 2013, at 4:59 p.m. EDT, the nearly two-mile-wide asteroid 1998 QE2 will pass by our planet at a distance of about 5.86 million km (3.64 million miles)… about 15 times the distance between Earth and the Moon. And although it poses no threat of impacting Earth neither during this pass nor in the foreseeable future, on the eve of its close approach NASA revealed a surprising discovery about this cosmic visitor: it has a little moon of its very own!
In daylight our big blue marble is all land, oceans and clouds. But the night is electric.
This image of North and South America at night is a composite assembled from data acquired by the Suomi NPP satellite in April and October 2012. The new data was mapped over existing Blue Marble imagery of Earth to provide a realistic view of the planet.
The nighttime view was made possible by the new satellite’s “day-night band” of the Visible Infrared Imaging Radiometer Suite. VIIRS detects light in a range of wavelengths from green to near-infrared and uses filtering techniques to observe dim signals such as city lights, gas flares, auroras, wildfires, and reflected moonlight. In this case, auroras, fires, and other stray light have been removed to emphasize the city lights.
Although the view looking down from space is of a sparkling show, the downside of course is light pollution over major metropolitan areas which impede the view of the night sky from the ground. (Find out more at the International Dark Sky Association site.)
Read more (and watch a video of these nighttime images of Earth) below:
It’s the 2012 version of the “Blue Marble“! Here’s an amazing new high-definition portrait of our planet, made by NASA’s Suomi NPP satellite launched back on October 28. This is a composite image created from multiple scans taken with the satellite’s Visible/Infrared Imager Radiometer Suite (VIIRS).
Suomi NPP is the first satellite designed to collect critical data to improve short-term weather forecasts and increase understanding of long-term climate change. It orbits Earth about 14 times each day and observes nearly the entire surface.
Credit: NASA/NOAA/GSFC/Suomi NPP/VIIRS/Norman Kuring
Here’s something interesting…
This Saturday I was looking at some timelapse video from the Canada-France-Hawaii Telescope’s Cloudcam… those are beautiful in their own right, but really I was interested in seeing if there was any visual of the reentering UARS. After doing some time-zone math, I realized that the satellite would be reentering before it was really dark over Hawaii, but I did see something unusual in this sequence from the 23rd-24th:
If you notice, around 21:33 HST (about 30 seconds in) in the video, there are some “ripples” high in the atmosphere visible in the upper left of the frame. These extend for some time before dissipating completely. Could that be a “shockwave” from the reentering UARS, further north and east on the globe? Based on this trajectory map, UARS could have reentered the atmosphere not too far from that site.
NASA scientists still aren’t exactly sure where and when UARS came down, but it’s suspected all remains went into the Pacific Ocean west of Canada.
I’m looking into this with those much more specialized in such things than I am. Stay tuned…
Video credit: Canada-France-Hawaii Telescope (Check out the original HD version on the site here.)
UPDATE: I am being told by a couple of experts that this may be “just” a case of high-level cirrus clouds, or else something created by the video compression. Not sure, I think I am going to look into it a bit further.
UPDATE 2: It’s 99% surely cirrus clouds. After hearing back from several reputable expert sources, and seeing where the UARS eventually did enter the atmosphere (off the eastern coast of Africa) it’s definitely not shock waves. Oh well. But that’s how you find things out… asking the right people their thoughts!
Watch as a huge cloud of ash bursts into the upper atmosphere from Iceland’s Grímsvötn volcano in this sequence of images taken by NASA’s GOES-13 weather observation satellite. The oblique angle of illumination and position along the edge of the globe emphasizes the incredible vertical scale of the eruption. (Click to play.)
Grímsvötn erupted on Saturday, May 21, sending an ash plume 12 miles high and closing local airports. Covered by glacial ice, the eruption was rather explosive and very dramatic…as seen in many photos circulating online today.
Iceland’s most active volcano, Grímsvötn hasn’t erupted this forcefully in almost a century.
After 7 years and almost 5 billion of miles of traveling around the blistering inner solar system NASA’s MESSENGER spacecraft is finally ready for the moment it was created for: orbital insertion around Mercury, the innermost planet!
At 9pm EDT tomorrow MESSENGER will attempt to establish orbit and if successful will become the first spacecraft ever to do so.
This is a highly technical maneuver, of course, so rather than try to paraphrase the details I will instead share the official release statement from the MESSENGER mission site here:
After more than a dozen laps through the inner solar system and six planetary flybys, NASA’s MESSENGER spacecraft will move into orbit around Mercury at around 9 p.m. EDT on March 17, 2011. The durable spacecraft — carrying seven science instruments and fortified against the blistering environs near the Sun — will be the first to orbit the innermost planet.
“From the outset of this mission, our goal has been to gather the first global observations of Mercury from orbit,” says MESSENGER Principal Investigator Sean Solomon, of the Carnegie Institution of Washington. “At the time of our launch more than six and a half years ago, that goal seemed but a distant dream. MESSENGER is now poised to turn that dream into reality.”
Just over 33 hours before the main Mercury orbit insertion maneuver, two antennas from NASA’s Deep Space Network — one main antenna and one backup — will begin to track the MESSENGER spacecraft continuously. At 6:30 p.m. EDT on March 17, the number of antennas tracking MESSENGER will increase to five — four of these will be arrayed together to enhance the signal from the spacecraft, and a fifth will be used for backup.
“At the time of our launch more than six and a half years ago, that goal seemed but a distant dream. MESSENGER is now poised to turn that dream into reality.”
– MESSENGER P.I. Sean Solomon, Carnegie Institution
At about 8 p.m., the solar arrays, telecommunications, attitude control, and autonomy systems will be configured for the main thruster firing (known as a “burn”), and the spacecraft, operating on commands transmitted last week from Earth, will be turned to the correct orientation for MESSENGER’s Mercury orbit insertion maneuver.
To slow the spacecraft down sufficiently to be “captured” by Mercury, MESSENGER’s main thruster will fire for about 15 minutes beginning at 8:45 p.m. This burn will slow the spacecraft by 1,929 miles per hour (862 meters per second) and consume 31 percent of the propellant that the spacecraft carried at launch. Less than 9.5 percent of the usable propellant at the start of the mission will remain after completing the orbit insertion maneuver, but the spacecraft will still have plenty of propellant for orbit adjustments during its yearlong science campaign.
After the burn, the spacecraft will turn toward Earth and resume normal operations. Data will be collected by Deep Space Network antennas and transferred to the Mission Operations Center at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md., to be analyzed. It is expected that by 10 p.m. EDT, mission operators will be able to confirm that MESSENGER has been successfully captured into orbit around Mercury.
The maneuver — which will be completed at a time that MESSENGER is more than 96 million miles from Earth — will place the probe into an orbit that brings it as close as 124 miles to Mercury’s surface. At 2:47 a.m. EDT on March 18, the spacecraft will begin its first full orbit around Mercury, and the probe will continue to orbit Mercury once every 12 hours for the duration of its primary mission.
“For the first two weeks of orbit, we’ll be focused on ensuring that the spacecraft systems are all working well in Mercury’s harsh thermal environment,” says APL’s Eric Finnegan, the MESSENGER Mission Systems Engineer. “Starting on March 23 the instruments will be turned on and checked out, and on April 4 the science phase of the mission will begin and the first orbital science data from Mercury will be returned.”
While in orbit, MESSENGER’s instruments will perform the first complete reconnaissance of the cratered planet’s geochemistry, geophysics, geological history, atmosphere, magnetosphere, and plasma environment.
“The marathon cruise phase of the MESSENGER mission is nearing the finish line,” says Solomon. “Like a seasoned runner, the MESSENGER team is positioned to break through the tape. We are extremely excited by the prospect that orbital operations will soon begin.”
Very exciting! Best of luck to MESSENGER and the mission scientists, I’m sure they’re all on the edges of their seats, as are we all! And stay tuned to LITD for more info and images, and follow my Twitter feed for updates as they are announced.
Here’s hoping all goes perfectly!
Image: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
ADDED: Want to watch the progress live from mission HQ? NASA TV will be airing MESSENGER status starting at 8pm EDT / 5pm PDT…click here to watch!