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UPDATE: Comet ISON, a "shining green candle in the solar wind," is no longer with us, NASA declared Monday morning December 3 in a tribute to what many hoped would be "the comet of the century."
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We continue our coverage from last month’s installment of what’s being heralded as the "Comet of the Century." Here’s what you can hopefully expect to see during this month:
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A bright new comet is on its way to gracing the pre-dawn morning sky toward the end of November and promises to put on quite a show during the first few weeks of December. Due to the time frame involved—and its potential for becoming the “Comet of the Century” as it’s being widely heralded—we’re devoting the Sky Talk columns both this month and next to its coverage.
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October for most of us means the real beginning of the fall season, with its lower humidity, cooler temperatures, lovely turning of the leaves, and beautifully clear nights for stargazing. It’s also the month of Halloween. For me, mention of October and this popular holiday mean something else as well—it takes me back to the night that Mars invaded the Earth!
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On July 20, 1969, the Apollo 11 reached the Moon. Millions watched as Neil Armstrong and Buzz Aldrin took their first steps on the surface. The United States had reached the Moon before the Soviet Union, and the first part of President Kennedy’s objective to the nation, of “landing a man on the moon and returning him safely to the earth,” had been fulfilled.
Now the three-man crew needed to get home.
Image courtesy of jsc.nasa.gov
After jettisoning the Lunar Module Eagle shortly before leaving lunar orbit and intentionally breaking off from the Service Module during the beginning of reentry, all that remained of the Apollo 11 craft was the Command Module Columbia, a truncated cone shorter than 11 feet in height (the Saturn V rocket that launched the Apollo 11 into space was over 300 feet tall). Columbia served as the crew quarters for the entire flight and housed most of the spacecraft systems, including the Earth Landing System. Michael Collins had stayed aboard Columbia in lunar orbit while Armstrong and Aldrin used Eagle to explore the Moon’s surface.
Columbia would have to put up with great temperature change during the mission; from the heat of launching from the earth’s surface to the cold of space, to taking on the direct heat of the sun, as well as the extreme heat of reentry. The temperatures would range between 280 degrees below zero and 5000 degrees above. To combat the temperature extremes, an ablative heat shield was used around the entire command module. The heat shield was designed to melt and erode away with the rising temperatures, taking the heat with it.
This heat shield was also covered with Kapton tape for added insulation. Developed by DuPont, Kapton is a polyimide film that is capable of withstanding extreme temperatures and hold up in these conditions. Kapton material was also used on the lunar module, as well as the astronauts’ spacesuits. Kapton is still used today for microelectronics, including flexible electronics and smartphones.
The chemical structure of Kapton. Image courtesy of Wikipedia.
As Columbia reentered the Earth’s atmosphere, it would appear on the outside as if the module was in a ball of flame, but on the inside, the astronauts were safely protected from the heat as it was repelled away with the melting shield. Columbia dropped into the Pacific Ocean on July 24, 1969, just before dawn local time. All three astronauts returned safely to the Earth.
While a lot of the heat shield and Kapton material burned up, a fair amount of it did survive reentry. Limited quantities of Kapton foil from the lunar missions have been known to go on sale. Interested buyers are always encouraged to make sure such items include certificates of authenticity when looking to own a little piece of history. It’s a marvel of technological advancement that such a thin reflective foil could make the difference between life and death for these intrepid explorers.
A collectible remnant of the Kapton foil from the Apollo 11 Command Module, which includes Certificate of Authenticity. Available for a limited time at Edmund Scientifics.
Artist concept of the Voyager probe in space. Image courtesy of NASA/JPL-Caltech
Earlier this month, NASA announced that the Voyager 1 probe had successfully entered interstellar space; the first human-made object to do so. As the probe continues forth into the vast unknown, it carries with it a special collection of “welcome signs” for any life forms it may encounter. Known as the Voyager Golden Record, this 12” gold plated copper disc was designed to operate similarly to a phonograph record. The disc is filled with sounds and images from Earth. Carefully selected by a committee led by Dr. Carl Sagan of Cornell University, the Voyager Golden Record includes the following:
Both the Voyager 1 and Voyager 2 probes carry a copy of the Voyager Golden Record. The record was designed to be played at a speed of 16 2/3 rotations per minute; half the speed of traditional vinyl records. Not to leave the greeting without an instruction manual, NASA meticulously crafted a cover for the record, using a collection of images and binary code to provide the proper setup needed to play the record that would transcend any language barrier. A stylus is included with the record to allow for it to be played.
A replica of the Voyager Golden Record cover, available at Edmund Scientifics. The record’s cover utilizes images and binary arithmetic to decipher instructions for playing the record.
The upper left portion of the record’s cover shows visual directions for how to properly play the record, including placement of the stylus to the record, playing from the outside of the record to the inside, and the speed at which to play the record. The lower left portion features a pulsar map, previously included on plaques for Voyager’s predecessors, the Pioneer 10 and 11 probes. The map shows the position of the sun in relation to 14 different pulsars. The upper right portion shows how to extrapolate the images from the disc, using the signal, which decodes to a series of 512 vertical lines. It also includes an image of a circle, the first image used to verify that the images have been decoded correctly. The time scale with which to use as reference is the final piece of the puzzle, showcased in the image on the bottom right. Instead of relying on seconds and minutes (derived from Earth’s rotation), the code on the Golden Record relies on the fundamental transition of the hydrogen atom (approximately 0,70 billionths of a second) as the preferred time scale.
While the likelihood of encountering intelligent life along Voyager 1’s current trajectory may be minimal (even equated by Dr. Sagan as tossing a “bottle into the cosmic ocean”), the Golden Record serves as a conscientious time capsule of tiny blue dot that is the planet Earth.
Voyager Fun Facts:
Source: http://voyager.jpl.nasa.gov
One’s first encounter with the Milky Way Galaxy Star Crystal may leave almost as much wonder as seeing NASA’s images of the galaxy itself; a bright, swirling mass of tiny bright dots hovering in a vacuum, or in this case a block of solid crystal.
Image: bathsheba.com
California artist Bathsheba Grossman has made a career for herself by creating a powerful marriage of art and science in her pieces; often utilizing construction techniques such as 3D printing to create intricate geometrical patterns and designs for sculptures, jewelry and other objects. In addition, Bathsheba has been creating brilliant three-dimensional images based on scientific imagery carved into crystal blocks. The images that are etched are referred to as laser-induced-damage images, or LIDI for short.
LIDI is a fascinating process that (as the name implies) cause small breaks in the glass with the use of a laser. The conical laser used is positioned with the proper focal depth to cause a tiny fracture within the crystal structure, leaving the rest of the block around the point of breakage intact. Each fracture, or “point”, measures approximately one tenth of a millimeter in size.
Like most of Bathsheba’s works, the process starts in the design phase. After much trial and error, Bathsheba now uses her own self-written CAD software to create a map of her image. Each “point” is carefully planned out. Several points may exist on one two-dimensional plane of the design. Several more on the next plane, and the next, and so on. Each point must be spaced far enough apart from one another to prevent the crystal from breaking, while being close enough to one another to give the look of the desired three-dimensional line or shape. The particular image of the Milky Way is derived images captured by NASA’s Goddard Space Flight Center.
After the hundreds of thousands of points are laid out in the CAD image, it is time to carve. A high-frequency Nd:YAG laser is used in this process, as a lower-frequency laser will create points that may appear fuzzy when viewed. The laser and crystal block remain stationary during the carving process; a mirror reflects the laser’s beam to properly place the laser’s focus to the correct location in the crystal. Points are created by pulsing the laser on and off once the mirror has been properly repositioned. This process is repeated several hundred thousand times in order to place every point along the structure. The image is carved from the rearmost plane to the frontmost, ensuring that previously carved points do not get in the way of placing new points. The end result is an impressive facsimile of the 300 billion stars in the Milky Way, suspended within the clear crystal structure.
In addition to the Milky Way, Bathsheda has also created LIDI crystal designs for a map of stars around our solar system, a double helix of DNA, the molecule for caffeine, the Calabi-Yau manifold from string theory and many others.
More of Bathsheba’s incredible work can be seen at her website.
Mark the three evenings of September 7th, 8th and 9th on your calendar to watch a fascinating interplay of the crescent Moon and two bright planets in the southwestern sky after sunset. And later in the month, another planet joins the parade. All of this will provide yet another example of the fact that the cosmic drama unfolding nightly overhead is alive with exciting action.
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The word "galaxy" is entrenched in the popular mind—everyone’s heard of these remote star cities, but with the exception of stargazers few have ever seen one. Or so they think. One of them has been readily visible to anyone who’s ever looked up at the summer sky on a dark clear night. It’s none other than our home galaxy, the Milky Way! And the best time of the year to see and experience it is late August into September.
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If you’ve ever wanted to see sunspots, now’s the time! Our "Daytime Star" is at its long anticipated sunspot maximum this year, with its visible surface peppered much of the time with dark spots of various sizes. Watching them develop and move across the face of the Sun from day-to-day as it slowly rotates is a fascinating activity. But extreme caution is required in doing so due to the overwhelming solar radiance.
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Many sophisticated methods of evaluating the optical quality of a telescope have been developed over the years. But there’s one very simple, convenient, and sensitive test that’s easy to perform any clear night. Known as the extrafocal image test, it uses an actual star as the test source.
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