The Spider, by Messenger

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

If you've followed this blog from the beginning, you were probably expecting a photo of Mars today, as we move outward through the Solar System away from the Sun. However, the Minister will occasionally interrupt his planned posts for breaking news and/or new images that are worthy of immediate attention. Such is the case today with a new photo of "the Spider," a geological feature on Mercury of an impact crater surrounded by numerous troughs pointing away from the crater, giving the impression of a very multi-legged spider:

The Narrow Angle Camera of the Mercury Dual Imaging System (MDIS) on the MESSENGER spacecraft obtained high-resolution images of the floor of the Caloris basin on January 14, 2008. Near the center of the basin, an area unseen by Mariner 10, this remarkable feature – nicknamed “the spider” by the science team – was revealed. A set of troughs radiates outward in a geometry unlike anything seen by Mariner 10. The radial troughs are interpreted to be the result of extension (breaking apart) of the floor materials that filled the Caloris basin after its formation. Other troughs near the center form a polygonal pattern. This type of polygonal pattern of troughs is also seen along the interior margin of the Caloris basin. An impact crater about 40 km (~25 miles) in diameter appears to be centered on “the spider.” The straight-line segments of the crater walls may have been influenced by preexisting extensional troughs, but some of the troughs may have formed at the time that the crater was excavated.

Apollo 17 at Taurus-Littrow, 1972

Credit: NASA

Like the Earth, a celestial body as unique as any other planet in our solar system, the Moon is far too often taken for granted by humanity. The Ministry for Space Exploration will post about the Moon as a celestial body, its past, present and future. While this blog cannot devote as much time to the Moon as it deserves, the Minister encourages readers to visit LPOD - Lunar Photo of the Day (the temporary site is located here) for more pictures and informative text about Earth's nearest celestial neighbor.

The above picture is of Harrison H. Schmitt of Apollo 17, who was photographed standing next to a huge, split boulder at the Taurus-Littrow landing site. Schmitt, who was a professional geologist, was also Apollo 17's lunar module pilot. After retiring from NASA, he served one term as a U.S. Senator from New Mexico.

This photograph was taken on December 13, 1972, by the Apollo 17 Commander, Astronaut Eugene A. Cernan.

Home

Credit: NASA (STS61A-34-0020)

While this blog will focus primarily on the solar system and beyond, the Ministry of Space Exploration won't neglect looking back at our own planet, which is a celestial body as interesting in its own right as any other. Just because we are most familiar with our world doesn't mean that we should take it for granted. This particular part of the Earth, the Finger Lakes region of upstate New York, has special meaning for the Minister of Space Exploration, as this is where he grew up. His hometown does not show on this particular image, but it's not too far from here, and he swam in two of the lakes shown above when he was a child, Keuka (which looks like a "U" on the left edge of the picture, although it's actually "Y" shaped) and Seneca (the lake to the right of Keuka). The Minister has not visited his hometown in over 20 years, but he would like to return there in the future, some day.

Individual agricultural fields are observable in this photograph of the two longest Finger Lakes—Seneca Lake (west) and Cayuga Lake (east). The smaller lake east of Cayuga Lake is Owasco Lake; the city of Auburn, New York, is located along the northern shore of Owasco Lake. While this region is known for general agriculture, dairying is extensive because of the close proximity to the dense population of the Mohawk River - Hudson River lowland from Buffalo to New York City. Grapes are also grown along the Finger Lakes where slopes ensure adequate air movement, which protects against frost, and where proximity to large water surfaces provides some ensurance against low temperatures.

This picture was taken by the crew of STS-61-A (Challenger) in October 1985.

Venus, by Venus Express

Credit: ESA © 2007 MPS/DLR-PF/IDA

This is a false-color image taken with the Venus Monitoring Camera (VMC) on board the European Space Agency's (ESA) Venus Express. It shows the full view of the southern hemisphere from the equator (right) to the pole. The south pole is surrounded by a dark oval feature. Moving to the right, away from the pole and towards the equator, we see streaky clouds, a bright mid-latitude band and mottled clouds in the convective sub-solar region.

This image was taken in the ultraviolet at 365 nanometers on 23 July 2007 as Venus Express was 35,000 km from the surface of the planet.

Are We There Yet?

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

This image demonstrates the first detection of Pluto using the high-resolution mode on the New Horizons Long-Range Reconnaissance Imager (LORRI). The mode provides a clear separation between Pluto and numerous nearby background stars. When the image was taken on October 6, 2007, Pluto was located in the constellation Serpens, in a region of the sky dense with background stars.

Typically, LORRI’s exposure time in hi-res mode is limited to approximately 0.1 seconds, but by using a special pointing mode that allowed an increase in the exposure time to 0.967 seconds, scientists were able to spot Pluto, which is approximately 15,000 times fainter than human eyes can detect.

New Horizons was still too far from Pluto (3.6 billion kilometers, or 2.2 billion miles) for LORRI to resolve any details on Pluto’s surface – that won’t happen until summer 2014, approximately one year before closest approach. For now the entire Pluto system remains a bright dot to the spacecraft’s telescopic camera, though LORRI is expected to start resolving Charon from Pluto – seeing them as separate objects – in summer 2010.

Mercury in Visible/Infrared Light, by Messenger

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

MESSENGER's Wide Angle Camera (WAC), part of the Mercury Dual Imaging System (MDIS), is equipped with 11 narrow-band color filters, in contrast to the two visible-light filters and one ultraviolet filter that were on Mariner 10's vidicon camera. By combining images taken through different filters in the visible and infrared, the MESSENGER data allow Mercury to be seen in a variety of high-resolution color views not previously possible. MESSENGER’s eyes can see far beyond the color range of the human eye, and the colors seen in the accompanying image are somewhat different from what a human would see.

The color image was generated by combining three separate images taken through WAC filters sensitive to light in different wavelengths; filters that transmit light with wavelengths of 1000, 700, and 430 nanometers (infrared, far red, and violet, respectively) were placed in the red, green, and blue channels, respectively, to create this image. The human eye is sensitive across only the wavelength range 400 to 700 nanometers. Creating a false-color image in this way accentuates color differences on Mercury's surface that cannot be seen in the single-filter, black-and-white image released last week.

This visible-infrared image shows an incoming view of Mercury, about 80 minutes before MESSENGER's closest pass of the planet on January 14, 2008, from a distance of about 27,000 kilometers (17,000 miles).

Image sequences acquired through the 11 different MDIS filters are being used to distinguish subtle color variations indicative of different rock types. By analyzing color differences across all 11 filters, the MESSENGER team is investigating the variety of mineral and rock types present on Mercury’s surface. Such information will be key to addressing fundamental questions about how Mercury formed and evolved.

Mercury has a diameter of about 4880 kilometers (3030 miles), and the smallest feature visible in this color image is about 10 kilometers (6 miles) in size.

Mercury's Sholem Aleichem Crater, by Messenger

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

The other day I wrote about the sense of humor the astronomers at APOD have. Now it's time to show some of the recent photos taken by the MESSENGER spacecraft that flew by the planet Mercury last week. This particular photo was taken last Monday, January 14th. The caption for the photo reads in part:

This image ... was acquired on January 14, 2008, 18:10 UTC, when the spacecraft was about 18,000 kilometers (11,000 miles) from the surface of Mercury, about 55 minutes before MESSENGER’s closest approach to the planet.

The image shows a variety of surface textures, including smooth plains at the center of the image, many impact craters (some with central peaks), and rough material that appears to have been ejected from the large crater to the lower right. This large 200-kilometer-wide (about 120 miles) crater was seen in less detail by Mariner 10 more than three decades ago and was named Sholem Aleichem for the Yiddish writer. In this MESSENGER image, it can be seen that the plains deposits filling the crater’s interior have been deformed by linear ridges. The shadowed area on the right of the image is the day-night boundary, known as the terminator.

One interesting fact that APOD pointed out is that many of the craters on Mercury are shallower than comparable craters on the Moon, the reason being the higher gravitational pull on Mercury, which "helps flatten tall structures like high crater walls."

As for Sholem Aleichem: He was a Russian Jewish writer (1859-1916) whose stories about Tevye the Milkman became the basis for the musical and film "Fiddler on the Roof."