Interactive Lunar Mosaic

Are you ready for some interactive spacey goodness? Stupid question, I know.

NASA recently released their Lunar Reconnaissance Orbiter Camera (LROC) Northern Polar Mosaic (LNPM). Using two Narrow Angle Cameras aboard their Lunar Reconnaissance Orbitor (LRO) along with additional information about the moon's topography from LRO's Lunar Orbiter Laser Altimeter and gravity information from NASA's Gravity Recovery and Interior Laboratory (GRAIL), they were able to create the largest high resolution mosaic of our moon’s north polar region. This mosaic is comprised of 10,581 six-and-a-half feet (two-meters)-per-pixel images covering an area equal to more than one-quarter of the United States. Put together, the entire image measures 931,070 pixels square. Do the math? That's almost 867 billion pixaels total!

And here's the interactive part: web viewers (that's you) can zoom in and out, and pan around an area. There is enough detail in these images that you can see textures and subtle shading of the lunar terrain, and the consistent lighting throughout the images makes it easy for you to compare different areas.

LROC Northern Polar Mosaic (LNPM) Interactive Website

Also check out more information about LRO at NASA's LRO website

and look through the complete collection of LROC Images

and NASA's Press Release "NASA Releases First Interactive Mosaic of Lunar North Pole"



(image via NASA's press release)

The Moon in 2.5 Seconds

This video of the Moon is from the NASA/Goddard Space Flight Center Scientific Visualization Studio and uses data from the Lunar Reconnaissance Orbiter and Lunar Orbiter Laser Altimeter (LOLA) to compresses one month into 12 seconds and one year into 2.5 minutes. This is how the Moon will look to us on Earth during the entire year of 2011. We always see the same side, or face, of the moon, but because of the tilt of the Moon's axis and the shape of its orbit we see that face from slightly different angles over the course of a month and year. This "wobble" isn't apparent to us as we see the moon every night and don't think about how it was the night(s) before, but over the course of this video it is apparent.



http://www.universetoday.com/86613/one-year-of-the-moon-in-2-5-minutes/#more-86613

Another Lunar Eclipse

Lunar Eclipse Timing Chart (via Universe Today)

 This one is gonna be good, and rare. On the night of June 15, 2011 the Moon will pass directly through the center of Earth's shadow cone. That means it will pass through the most complete, darkest part of the Earth's shadow, giving the moon a red or orange hue. This type of eclipse hasn't occurred in 11 years and will not happen again until 2018.

The eclipse visibility path will be rising over South America, western Africa and Europe, and setting over eastern Asia. If you are in western Asia, Australia, or the Philippines the eclipse should be visible just before sunrise.

Still not sure if you are in the lunar eclipse zone? Check on the map HERE to find out.

Here are your eclipse start and end times:

Penumbral Eclipse    Begins: 17:24:34 UT
 Partial Eclipse          Begins: 18:22:56 UT
 Total Eclipse             Begins: 19:22:30 UT
 Greatest Eclipse:      Begins: 20:12:37 UT
 Total Eclipse:             Ends:   21:02:42 UT
 Partial Eclipse:          Ends:   22:02:15 UT
 Penumbral Eclipse:    Ends:   23:00:45 UT

Did none of that make sense? Click HERE for an easy-to-read explanation of of shadow zone terms.

If you are like me and live in a place where you won't be able to see the eclipse that's OK. You can still see it via the Intenet. Check out the AstronomyLive.com website and SLOOH for live broadcasts!

If you want the technical specs of the eclipse then visit NASA's 2011 eclipses page:  http://eclipse.gsfc.nasa.gov/OH/OH2011.html

Also:
http://www.universetoday.com/86522/coming-up-june-15th-total-lunar-eclipse-live/#more-86522

The Amazing Supermoon

Tomorrow night (March 19th) will be a perfect night for a moonlit stroll. Not just any moonlit stroll but a Supermoonlit stroll. Now, we've all see the illusion where the moon looks huge in the night sky, and it is just that, an illusion.The Moon isn't actually bigger or smaller as it travels across the sky. Why you see the Moon looking huge when it is low on the horizon is an optical illusion owing to the circuitry in your brain. There is no clear consensus on why. It could be an Ebbinghaus Illusion - where identically sized objects appear to be different sizes when placed in different surroundings (click link for picture) - the objects of known size to your brain that are near the horizon (trees, houses, etc.) provide a false frame of reference for the size of the Moon. When the Moon is high in the sky you have no such references and so see the Moon as smaller. Another possibility is how our brains interpret foreground objects for reference in terms of distance and size. Foreground objects of known size appear to be far away and so when something large, like the Moon, appears behind it and even farther away but still appears big then we interpret is as being larger than it is.

In the case of tomorrow night's Moon, it will actually be larger in the sky. Our Moon has an elliptical orbit around the Earth with one side of the ellipse, perigee, about 31,000 miles (50,000 km) closer than the other side, apogee. The moon will be in the perigee part of the orbit which will take it closer to Earth than it has been in two decades, since March 1993. This means that the moon will appear about 14% bigger and 30% brighter than when the it is in apogee (other side of the ellipse). Admittedly, that isn't all that big of a difference. It can be tricky to even tell the change in size, especially if you have no scale for reference, but the best time to look will be when the moon is near the horizon. This will be when the illusion of a bigger moon mixes with the reality of a closer moon to produce an amazing view.

Oh, and no, there will not be any cataclysmic, apocalyptic results of a close moon. Only slightly stronger tides.

Here's some more info:
http://www.abc.net.au/news/stories/2011/03/18/3168089.htm
http://www.universetoday.com/83998/the-supermoon-illusion/
http://science.nasa.gov/science-news/science-at-nasa/2011/16mar_supermoon/

(image from universetoday article)

Sandy Solutions

Apparently it is a wonderful day for astronomical news. Who knew? I'm one of those people who loves to read about astronomy (particularly planetary science) but never actually goes outside and looks up. Anyway, this next story I found in a couple of places and thought it was pretty interesting.

Way back in 1655 Christian Huygens discovered the moon Titan orbiting around Saturn. In fact, it is Saturn's largest moon and for a long time it was thought to be the largest moon in the solar system. After all, it is bigger than the planet Mercury. Alas, it was then realized we had based that judgement by measuring from the center to the edge of the atmosphere instead of from the center to the surface. But a big ole thick atmosphere on a moon is pretty neat all in itself. The moon runs about -180 degrees Celsius (-290 degrees Fahrenheit), cold enough for liquid methane to rain down and collect into lakes, rivers, and seas. Other parts of the surface, particularly the equatorial regions, are covered in giant sand dunes. These dunes are approximately 1 km (~0.5mi) wide, tens to hundreds of kilometers long, more than 100 m (300ft) high, and composed of organic hydrocarbons.

So lets take a look at a particular paradox that exhists on Titan. What we know about the rotation of planetary atmospheres plus data from the Huygens probe (which landed on Titan's surface) tells us that surface winds should go east to west. Then the Cassini spacecraft sent images of Titan's equatorial dunes which suggested that the winds were moving west to east. A new paper in Aeolian Research, and a related paper in Science, attempt to explain this phenomenon.

These papers propose that there are seasonal changes on Titan that reverse the wind patterns for a short period. The equinoxes appear to be particuarly important. Now it is easy to start thinking of other planets like you think of your own, but Saturn is a large planet to orbit around and it is very far away from the sun. One year on Titan is about 29 Earth years, and during that time the moon will have two equinoxes. These are times when the heat from the sun creates atmospheric upwellings, causing the winds to reverse and accelerate (kinda like monsoons on Earth). Short gusts of west-to-east winds occurring intermittently over two years are so strong that they transport the dunes' sand more effectively than the normal east-to-west winds, causing these reverse striations in the dunes.

Take a look through the articles:
Tokano, Tetsuya. (2010) Relevance of fast westerlies at equinox for the eastward elongation of Titan's dunes. Aeolian Research: In press. (DOI: 10.1016/j.aeolia.2010.04.003)

Lorenz, Ralph D. (2010) Winds of Change on Titan. Science: 329(5991), 519 - 520. (DOI: 10.1126/science.1192840)

and...
http://www.sciencedaily.com/releases/2010/07/100729205552.htm

(image credit: NASA/JPL)

The Astronomers Saga: Eclipse

Did you know? There is a partial lunar eclipse that will happen early Saturday (June 26th) that should be especially neat to those of us who live in North America. A lunar eclipse occurs when the moon passes through the Earth's shadow. This particular eclipse will create an optical illusion, or "moon illusion," that will make the moon look larger than normal. 53.7% of the moon's diameter will be covered at the peak of the eclipse, leaving lit almost half of the moon's disk on the shadow's outer fringe (penumbra).

The event will start at 6:17 a.m. EDT (1017 GMT) Saturday morning, the greatest eclipse occurring at around 7:38 a.m. EDT (1138 GMT). The entire show should last about 80 minutes, so if you want to go back to bed I suggest setting your alarm for the peak of the partial eclipse. If you live in the central or western part of the U.S. then look low and to the west just before dawn, the moon will be close to the horizon (peak should be ~4:35 a.m. PDT for you guys). If you live in the eastern U.S. the partial eclipse will begin after the moon has set so you may only get to see part of it. However, if you live in the northeastern U.S. and Canada, sorry no eclipse for you. If you are in India, Japan or parts of East Asia then you will be able to see the partial eclipse, "moon illusion" included, on Saturday evening as the moon rises.

Note that no special viewing equipment is needed for viewing a lunar eclipse, but if you have a telescope, and don't mind dragging it out at 4 in the morning, you'll notice some great coloration (see first link for details). Also, the International Space Station will be visible moving from west to southeast around 4:34 a.m. PDT (altitude 25 degrees SW).

The next lunar eclipse will happen on the morning of December 21, and it'll be a full one.

For more on times, details, etc look here:
http://www.space.com/spacewatch/partial-lunar-eclipse-coming-june-26-100618.html
http://www.space.com/spacewatch/moon-illusion-Saturday-eclipse-100625.html
http://www.katu.com/news/local/97174344.html

Pac Man Moon

I'm one of those people who is fascinated by astronomy but who never actually looks through a telescope at the sky above. But I do read the occasional astronomy news blog or two. One I like to scroll through on occasion is Universe Today, where I found this one.

I'll bet you didn't know that the Death Star is located in orbit around Saturn. Yeah, alright, so its just the moon Mimas, but it is down right weird how much it looks like the Death Star. The small moon has a giant crater (the Herschel Crater) that gives it that uniquely Death Star quality.

A recently flyby of Cassini of the moon Mimas generated some new temperature maps of its surface. These temperature maps reveal curious hot regions in/on the moon - hot regions that look just like Pac Man eating the Herschel Crater. These hot regions average around 92 Kelvin (-294 degrees Fahrenheit) as opposed to the cooler regions that are about 77 Kelvin (-320 degrees Fahrenheit). Cassini scientists believe that these temperature regions may be related to the differences in surface textures and how those textures retain or lose heat. It could also be due to ice (and its evaporative and reflective properties) spread across the surface upon the formation of the Herschel Crater. Alternatively, it could be due to how the moon ages and the accumulation of minerals and various particles.

As with most of the cool things in science, more study is needed.

Check out the story here: http://www.universetoday.com/2010/03/29/pacman-eats-the-death-star/#more-61205
and some really neat images of this discovery here: http://www.ciclops.org/view_event/132/Closest_Views_of_Cratered_Mimas?js=1

Titanic Layers

In 1655 Christian Huygens, back in 1655 discovered Titan, the largest moon of Saturn. Not long after, Giovanni Cassini discovered the next moons, Tethys, Dione and Iapetus. Now you know where the Cassini-Huygens spacecraft got its name. However,John Herschel was the person who actually named Saturn's moons in 1847. Herschel named the seven moons that were known at that time after the Greek Titans. He thought it made sense that the brothers of Cronus (the Roman name for the Greek god Saturn) should be included as the names of the moons. Since that time many other moons have been found hiding amongst the rings of Saturn; They're up into the mid-fifties now.

Titan is the biggest of Saturn's moons and one of the largest moons in the solar system - bigger than the planet Mercury! Its a moon that actually has an atmosphere - a really thick one. This atmosphere is about 98% nitrogen, the only other nitrogen-rich atmosphere in the solar system, and the remaining gases are composed primarily of methane and other hydrocarbons. Titan's atmosphere is a Hadley cell, meaning warm air at the equator rises, flows at high altitudes to the poles, and then descends again, and then moves along the surface. The result of this is extremely dry equatorial regions and "wet" polar regions. Its also extremely cold, around -180 Celsius (-290 degrees Fahrenheit). The mixture of this Hadley cell and the extremely cold temperatures allows methane to rain down in the polar regions.

The evolution of Titan is thought to be different than that of the inner planets or the Jovian moons (which are of a similar size and density), both of which have interiors that have split into distinctive layers.

The Cassini-Huygens spacecraft arrived to study the Saturn system in 2004, and has since made some amazing discoveries. In today's issue of Science, two articles revealed more interesting details about Saturn's largest moon. The Sohl article, on page 1338, revealed details about the moon's interior, also referring to a second study about the Titan's gravitational field. On page 1367 of the issue, Iess et al. presented evidence on the gravitational field of Titan, revealing that the interior of the moon was much colder than previously thought. Why is that important? Well, it informs us about how the internal materials are distributed; this extreme cold impeded the melting and subsequent separations of the primordial ice-rock mixture during moon formation. Only about the first 300 miles deep of Titan's icy surface is rock free, below that you see this ice-rock mixture. This information suggests that Titan more similar to Jupiter's moon Callisto, which is believed to have a similar interior, even though these moons have radically different histories.


Read the story here: http://www.sciencedaily.com/releases/2010/03/100311143830.htm
and the original Science articles here: http://www.sciencemag.org/cgi/content/summary/327/5971/1338

(top image from jpl.nasa.gov)

Big Badda-Boom

(images from news.nationalgeographic.com, phy.olemiss.edu, popsci.com, nasa.gov)

To get the gist of this next story a short history of your planet-moon system is in order.

During our solar system's formation it was a violent place. Everything running into everything else. Planets sucking up material and clearing out their orbits. During this time moons were forming around planets and planets were capturing objects and making them moons. Not so with the Earth's moon. The current, accepted theory is that a Mars-sized object collided with the Earth knocking off a massive amount of material. This material stayed in orbit around the planet (think big cloud then ring), eventually collapsing together and cooling to form our Moon. Samples brought back from Moon missions were chemically analysed and found to be very similar to mineral concentrations and isotopes found on Earth, strengthening this theory.

A recent study of the Moon has showed that an asteroid hit the southern hemisphere of the Moon. An enormous crater, approximately 1,500 miles across and five miles deep, resulted from the impact - the biggest, deepest crater on the Moon, the South Pole-Aitken basin.

So why, with all of the craters on the Moon, is this so important? Well, the asteroid impact punched through many layers of the Moon's crust, scattering it across the Moon and even into space. A 300 mile diameter crater - the Apollo Basin - on the edge of this basin provides a cross-sectional view of the lunar crust. It is rare that such glimpses into the surface of planets/moons occur. These deep views of the surface can provide much information about early lunar history.

Results from this study show that as you go deeper into the Moon, the crust contains larger amounts of iron. Think back to the story above and what you know of the concentrations of minerals on and inside the Earth. When the Moon was first forming it was largely molten - big collisions cause big amounts of heat. This fluid-like state allowed heavier elements (such as iron) to sink towards the core, leaving light elements (silicon, potassium, sodium, etc) to 'float' near the surface. So it makes sense that deeper impact craters expose more of these heavier elements, and that is what the researchers are finding.

Additionally, these craters are relatively old. How do you know if a crater is young or old? As time passes and the surface continues to get hit my objects, old craters get covered up by new craters. This provides a relative age. And although the Earth and the Moon were formed from the same pool of materials, you do not see the same cratering on the Earth that you see on the Moon. Why? It isn't that the Earth hasn't been impacted, it has and repeatedly. Its just that on the Earth the crust is constantly recycled by plate tectonics and worn away by weathering events. So the old, deep craters on the Moon actually give us a window into not only the Moon's history but the Earth's as well.

Read more by following this link: http://www.sciencedaily.com/releases/2010/03/100304165918.htm

Update as of 03-10-10: Just published in Nature, a story about the Moon origin theory:

http://www.nature.com/news/2010/100309/full/464150a.html