Tag Archives: crater

See Neil Armstrong’s crater on the moon

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A closeup view from orbit shows the pair of 18.5 mile-diameter craters Ritter and Sabine which are easily visible in a small telescope. They’ll help to guide you to the three smaller craters named after the Apollo 11 astronauts. North is up in the photo. Click to scout around an interactive moon map. Credit: NASA

Neil Armstrong will always have a place on the moon alongside his fellow Apollo astronauts Michael Collins and Buzz Aldrin. Each has a crater in their name not far from the Apollo 11 landing site in the Sea of Tranquillity. These three craters and three on the lunar farside for the crew of Apollo 8 are the only ones to my knowledge named for living  astronauts. Frank Borman, James Lovell and William Anders of Apollo 8 were the first the leave Earth orbit and travel around the moon.

14 other astronauts and cosmonauts who died while involved in their respective space programs have also been memorialized with craters. The most recent were seven craters named for the Space Shuttle Challenger astronauts who perished during while ascending to orbit after launch on January 28, 1986.

The astronauts who died in the Space Shuttle Columbia explosion while returning from orbit on February 1, 2003 are remembered in a cluster of craters in the Apollo Basin on the lunar farside and in seven named peaks in the Columbia Hills on the planet Mars. This range is located in Gusev Crater where the Spirit Rover landed in 2004.

You can start with this photo to first identify one of the man in the moon’s eyes – the Sea of Tranquillity. The photo map below will help you hone in on the trio of Armstrong, Aldrin and Collins. Photo: Bob King

Several years back on a clear night with little air turbulence, I trained my 10-inch telescope on the Apollo 11 landing site near the pair of medium-sized craters Ritter and Sabine. The site itself appears smooth and featureless to the eye, but Armstrong’s crater, along with his pals Buzz Aldrin and Michael Collins, who remained in orbit while the other two gathered rocks and set up experiments on the lunar surface, came into view at a magnification of around 200x.

All three form a neat little row with Armstrong the largest and Collins the smallest, but they’re all quite small really. Armstrong’s crater is just 2.9 miles across, Aldrin 2.1 miles and Collins 1.5 miles. The trio is located a short distance due north of the bright crater Moltke. With a 6-inch scope and steady air, you should be able to pick out all three out at high magnification starting about the time the moon is 6 days old or just before 1st quarter phase. Neil’s is the easiest to see.

Be patient. Unsteady air may cause them to waver and dissolve. If you keep your eye glued to the eyepiece, you’ll catch a few ideal moments when the trio will be tack sharp. I enjoyed the experience of seeing these “buddies for all of time” and picturing the nearby landing site.

In this tighter view, I’ve labeled Sabine, Ritter and the bright little crater Moltke along the eastern edge of the Sea of Tranquillity.  Once you’ve found your way to these craters, switch to high magnification and use the photo at the top of this blog to navigate to Armstrong and the others. Credit: Frank Barrett

Here are some photos to help you find them, too. The best time to look would be around the 6-8 day-old moon when shading and shadows will help reveal the craters’ contours, but feel free to try at any phase. Good luck in your explorations. Should you succeed, you will have taken one impressive leap for an amateur sky watcher.

How about this perspective? A view out the window of the lunar lander module looking back toward the command service module and the site where Armstrong and Aldrin would soon land. Credit: NASA

Want to learn more about Apollo 11? Read an excellent re-telling of the first lunar landing and what it was like to be there in the NASA Science News article Wide Awake in the Sea of Tranquillity.

Mars gives birth to twins and triplets

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The 27.5-hour-old crescent floats on its side in the western sky last night around 6:30 p.m. The faint outline of the earthlit moon is also visible. Details: 200mm lens at f/2.8, ISO 800 and 1/50" exposure. Photo: Bob King

It wasn’t so much how low the thin crescent moon was last night that made it tricky to see, but how faint. I looked off to the west 25 minutes after sunset and saw Jupiter, but where was the moon? After a bit more searching I finally found it, thin as shaved ice in a cold cup of blue sky.

Shadowed craters on a 2-day-old moon in 2009. Photo: Bob King

Binoculars enhanced the view and made the crescent look crumbly or broken. Segments of brightly lit moon alternated with dark spots created by shadow-filled craters and shadows cast by peaks and crater walls.

The sun comes in at a very low angle on a day-old crescent moon just as it does at sunrise here on Earth, touching only the tops of trees and buildings while leaving streets and valleys in shadow. This shadow effect is more dramatic at extreme crescent phases, because then we see the moon at a glancing angle rather than face on. Shadows stack up across our line of sight “chopping up” the edgy crescent.

Notice the the uneven play of light along the length of last night's crescent moon created by alternating areas of sunlit surface and dark shadows. Details: 400mm lens at f/5.6. Photo: Bob King

Bathed in pink twilight light, the moon grew slightly brighter as twilight deepened, but unless you looked for it, you wouldn’t have known it was there. A beautiful if evanescent sight.  I do hope some of you were able to see it. Tonight a brighter, slightly thicker moon will lie to the right of Jupiter in twilight.

A remarkable pair of "conjoined twin" craters on Mars. Credit: NASA/JPL/University of Arizona

Mars has been in the news recently with new photos returned of rare double and triple craters by NASA’s Mars Reconnaisance Orbiter (MRO). The symmetry of these two side-by-side impacts tells us that the impacts must have happened nearly simultaneously, otherwise one would undoubtedly overlap the other. The twins share a common wall and their impact debris forms neat plumes of surface deposits above and below them.

Multiple pictures of the 135-mile-long asteroid 216 Kleopatra photographed by reflected radio waves. Credit: Stephen Ostro et al. (JPL), Arecibo Radio Telescope, NSF, NASA

Scientists believe the meteorite that created the two broke into two large pieces when it entered Mars atmosphere. With little time to separate before hitting the surface, the two struck almost simultaneously side by side, excavating nearly identical craters. While it’s unusual enough for this to happen, what’s even odder is that the object must have split into two nearly equal parts on its way down.

Perhaps it was dogbone-shaped like the asteroid 216 Kleopatra. Scientists think its weird shape is the result of a collision between two separate bodies that stuck together over time. During atmosphere entry on Mars, a similar though smaller “dogbone” may have been severed in two by powerful air pressures.

The floors of each of this triplet crater are covered in windblown sand dunes. Credit: NASA/JPL/U. of Arizona

Fond of twins but looking for something even more extraordinary? How about triplets? This MRO photo was released earlier this week and shows not one, not two but three craters formed by the breakup of a large meteorite/asteroid when it struck the planet sometime in the distant past. Anyone one for quadruplets?

This is such a blast!

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A fresh crater in the Arabia Terra region of Mars photographed by the Mars Global Surveyor. The impact occurred sometime between December 8, 2003 and November 26, 2005. The dark rings and rays around the crater were created by the expanding shock wave of the impact. The long rays and dark spots are secondary impacts when material from the crust was thrown outward from the explosion. Credit: NASA/JPL/MSSS

This is such a neat image. So many of the craters we see in photos are on the order of several billion years old that it comes as an unexpected surprise to stumble upon a fresh one. This impact on Mars is only 75 feet across – about as big as your front yard – and shows beautiful wispy tendrils of dark debris extending from the blast zone. The Mars Global Surveyor mission found 20 new, small impact craters during its continuous monitoring of the planet between May 1999 and March 2006.  Click the link and take a look at them when you have time.

I find parallels between Earth and alien worlds fascinating. Mars gets an occasional smack by a meteorite just like Earth does. Many that hit our planet land in the ocean and leave no impression, but since Mars lacks surface water,  just about any worthy impact leaves its mark for the remote eye of a spacecraft to see.

Before and after photos of the Arabia crater impact. The left photo was taken in December 2003; the circle is the area where the impact had yet to occur. The right image is from November 2005 after the new crater had formed. The crater appears white rather than dark because it was photographed in infrared (heat) light. Credit: NASA/JPL/Malin Space Science Systems

No other planet draws like Mars. There are currently three orbiting probes studying and photographing Mars’ surface and weather every day. Down on the ground, the Opportunity Rover is halfway along its 11.8 mile journey from Victoria Crater to Endeavor Crater. Come next January, Opportunity will have been operational for seven years – that’s six years and nine months longer than planned. No one’s heard from the Spirit Rover since March 22. It got mired in sand in 2009 and has been nearly stationery since. The robot is currently in hibernation mode during the long Martian winter and hasn’t responded to commands from Earth. If mission controllers don’t hear from it by next March, that’ll probably spell the end of its mission.

Engineers working in a clean room at NASA's Jet Propulsion Laboratory, installed six new wheels on the Curiosity rover, and rotated all six wheels at once on July 9, 2010. Credit: NASA/JPL-Caltech

The next generation “super rover” Curiosity will be launched in the fall of 2011. At 9 feet, it’s twice as long as Spirit and Opportunity and loaded with instruments to assess whether Mars ever had an environment capable of supporting microbial life and conditions that may have preserved clues about its existence. Multiple cameras, a laser for zapping rocks, an instrument to search for organic compounds and a nifty nuclear battery to keep everything running year round. This baby is deluxe! I don’t know about you, but I can’t get enough of Mars.

Researcher finds new meteor crater without leaving home

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The newly discovered Gebel Kamil crater in southern Egypt is a little wider than a football field and still relatively fresh. Credit: Landsat image from Google Earth

Imagine scanning through images in Google Earth and stumbling across a meteor crater made by a hunk of flying iron from the asteroid belt. That’s just what Vincenzo de Michele, former curator of the Natural History Museum in Milan, Italy did while scouring satellite photos in search of new impact craters. Not long after, in February 2009, he and others undertook an expedition to the site in southern Egypt near the Sudanese border to verify whether it was a true crater.

Oh yes indeed it was.

They found thousands of fragments of nickel-iron meteorites scattered in and around the Kamil Crater, a modest hole in the ground 184 feet across and 52 feet deep. What’s amazing is how fresh the crater is – check out those rays of colorful rock spray still visible beyond the crater’s rim. Scientists estimate the original meteorite was about 5 feet across, weighed 10 tons and fell some 5000 years ago.

The largest Gebel Kamil meteorite found so far - a 183 lb. thumbprinted beauty. Credit: Univ. of Siena / Museo Nazionale dell'Antartide, courtesy Dr. Luigi Folco

This past February, a combined Italian-Egyptian geophysical expedition made a careful survey of Kamil Crater and recovered 5,178 meteorite fragments – plus impact-related glasses – totaling 1.7 tons! The largest fragment weighs 183 lbs. (83 kg) and its surface is covered with beautiful regmaglypts or “thumbprints” created when the fierce heat of atmospheric entry melted softer spots which sloughed off during flight. Most of the meteorites have torn and ripped shapes indicating that the original mass likely exploded during flight due to a good pounding by the atmosphere.

The Kamil crater is 184 feet across with an upraised rim of blasted rock about 10 feet high. The interior is partially filled with sand. Credit: Univ. of Siena / Museo Nazionale dell'Antartide, courtesy Dr. Luigi Folco

The meteorite, now known as Gebel Kamil, after a distinctive spire of rock in the area, is different from many iron meteorites because it contains an unusually large amount of nickel. Most irons contain between 5-10% nickel but Gebel Kamil is loaded with 20%. This makes it a considerably rarer type of iron meteorite called an ataxite. The irons from Meteor Crater east of Flagstaff, Arizona are of a more common variety containing less nickel.

A typical Gebel Kamil meteorite (left) looks like a grenade or bomb fragment (shrapnel). The photo of the slice at right shows additional minerals inside and an interesting stress pattern in the metal. Photos: Bob King

So you can experience a little of the adventure yourself in finding a meteorite crater, this link will bring you to Google Earth where you can explore the Kamil crater and vicinity from your very own desktop. Lots more photos posted by the February expedition team are HERE.