Universe Today

Our Moon. Image credit: Blackett Observatory. Click to enlarge.
Monday, November 7 – Tonight Mars is at opposition, meaning that it rises just as Sol sets. Be sure to be outside at twilight to catch the awesome appearance of Venus to the west/southwest and Mars rivaling it in the east. You don’t want to miss this outstanding pair.

While the bright planets will try to steal the show, no place on the lunar surface can steal your heart like the Caucasus Mountains. Located tonight along the terminator in the north, stop and really take the time to appreciate their beauty. Like the earthly Caucasus which stretches 1500 kilometers between the Black and Caspian Seas, these stunning mountains extend 500 kilometers between the lunar “seas” of Mare Frigoris and Mare Serenitatis. While most of us could never climb to the 5642 meter summit of Mt. Eibrus, we can match that with our eyes as we power up to look at small crater Callipus caught in Caucasus’ midst. The highest peak is to its west and rises to a stunning 5303 meters above the desolate surface.

Climb the mountains. Their slopes, enclaves and plateaus were formed by the same volcanic process as those bordering Asia Minor. Look for Aristoteles and Eudoxus to the north-east, sitting like small countries along the borders. Where your imagination takes you is 384,000 kilometers away…

Tuesday, November 8 – Born on this day 1656, the great Edmund Halley made his mark on history as he became best known for determining the orbital period of the comet which bears his name. English scientist Halley, had many talents however, and in 1718 discovered what were referred to as “fixed stars”, actually displayed proper motion. If it were not for Halley, Sir Isaac Newton may never have published his now famous work on the laws of gravity and motion. Tonight let’s honor Halley by observing one of the all time greatest of double stars in motion – Almach.

Gamma Andromedae is the last in the chain of bright stars that extends from the northern-eastern corner of the “Square of Pegasus”. It may have been discovered to be a double as early as 1788, but F.W. Struve was the first to record its measurements in 1830. To even the smallest of telescopes, its golden primary is easily separated from the blue-green secondary, but for larger scopes – there’s something more.

In 1842, Struve discovered the companion star is itself a very close double of similar magnitude and spectral type. In 1982 they reached their maximum separation of .5, but it is possible to see them as companion stars thanks to their highly ellipitcal orbits. The brighter of the two is also a spectroscopic binary, making this a quadruple system. The light you see tonight from this beautifully colored pair left 3 years after Halley’s death.

Wednesday, November 9 – Be sure to take binoculars out just after sunset to catch Antares and Mercury within two degrees of each other. Both will be very low on the horizon, so don’t wait too long…

Tonight the Moon will be closest to Earth, so let’s get a good close look at striking trio of craters just south of central along the terminator. The smallest and youngest of the three is Arzachel at the southern end of the chain and far larger and older Ptolemy is to the north. Look closely at central crater Alphonsus, for it is the only crater to have photographic proof that changes do occur on the lunar surface. On October 26, 1956 a photo was taken showing a strange cloud just east of its central peak. Russian astronomer, Nikolai Kozyrev was fascinated and doggedly observed and photographed a changing Alphonsus until he had a huge success of the night of November 2, 1958. In taking a series of spectrograms (not an easy feat for those times and equipment), he successfully captured unmistakable evidence of a cloud of carbon molecule “outgassing”. Spaseba!

Today is the birthdate of Carl Sagan. Born in 1934 Sagan was an American planetologist, exobiologist, popularizer of science and astronomy, and novelist. His influential work and enthusiasm inspired us all. In his memory, tonight we’ll have a look at Melotte 25.

Most of you will recognize this expansive open cluster as the V-shaped group that forms the “head” of Taurus – more commonly referred to as the Hyades. Hundreds of mixed magnitude stars are contained inside this fist-sized cluster. The brightest true member is Theta 2, followed by its slightly dimmer counterpart – Theta 1. You’ll find this pair easily with binoculars just south of orange Aldeberan, which is merely a foreground star in this stellar play. At roughly 150 light years away, it’s the closest open cluster known after the Ursa Major group. At 400 million years old, it moves away from us and perhaps carries the spirit of Sagan with it… “We are all just star stuff.”

Thursday, November 10 – Tonight no crater on the Moon will call louder than the mighty Copernicus – so let’s answer.

With its thick walls and central peak, it is wonderfully picturesque, but what’s around the mound? To the north is two part crater – Gay-Lussac. Look for its stunning rimae cutting diagonally away to the southwest. To the south is an even smaller double crater – Fauth. If you want a true challenge, power up to the max. Look inside of Copernicus on the east wall for the very tiny strike of crater A!

Friday, November 11 – A true observer was born on this day 1875. His name was Vesto Slipher, who spent some very quality time with the 60″ and 100″ telescopes on Mt. Wilson. Slipher was the first to photograph galaxy spectra and measure their redshifts, which led to the discovery of the expansion of the universe by Edwin Hubble.

Tonight let’s take a look at a galaxy as we head once again towards Andromeda and M31. Although the moonlight will prevent us from seeing great details, it is still quite amazing to know that we are able to see across 2.2 million light years. Containing over 300 billion stars, its one of the largest galaxies known. In 1912, Slipher analyzed it spectroscopically to discover its blue shift: “The magnitude of this velocity, which is the greatest hitherto observed, raises the question whether the velocity-like displacement might not be due to some other cause, but I believe we have at the moment we have no other interpretation for it. Hence we may conclude the Andromeda Nebula is approaching the solar system with a velocity of about 3000 kilometers per second.”

Saturday, November 12 – Wouldn’t we all have loved to have been there in 1949 when the first scientific observations were made with the Palomar 5-meter (200-inch) telescope? Or to have seen what Voyager 1 saw as it made its closest approach to Saturn on this date in 1980? Or even better, to have been around in 1833 – the night of the Great Leonid Meteor Shower! But this is here and now, so let’s make our own mark on the night sky as we view the Northern Taurid meteor shower.

Already making headlines around the world for producing extremely bright fireballs known as bolides, this particular stream belongs to debris left by periodic comet Encke. According to meteor experts Asher and Clube, 2005 could quite possibly be the year we pass through the “swarm” – a particularly rocky pocket of materials capable of producing these spectacular meteors. Although the Moon will greatly interfere with fainter members, a bolide can be spotted even through hazy cloud cover!

While you’re out, be sure to also keep watch for members of the Pegasid meteor shower, whose radiant is roughly near Square. This stream endures from mid-October until late November and used to be quite spectacular. Watch for the peak on November 17.

Sunday, November 13 – Today is the birthday of James Clerk Maxwell. Born in 1831, Maxwell was a leading English theoretician in electromagnetism and the nature of light. On this day in 1971, Mariner 9 becomes the first spaceprobe to orbit Mars.

Tonight let’s have a look at again at orbiting Mars. Depending on your observing time, perhaps you’ll catch the deep wedge of Syrtis Major punctuated by the Hellas Basin. For another, it might be the “moose antler” look of Mare Cimmerium or the red fields of Amazonis. Still others might catch the “fingers” of Mare Erythraeum reaching toward Chryse… No matter what time you look, it’s time well spent.

Until next week? May all your journeys be at light speed… ~Tammy Plotner

Artist illustration of Venus Express. Image credit: ESA. Click to enlarge.
University of Colorado at Boulder planetary scientist Larry Esposito, a member of the European Space Agency’s Venus Express science team, believes the upcoming mission to Earth’s “evil twin” planet should be full of surprises.

While its 875-degree F. surface is hot enough to make rocks glow and its atmosphere is filled with noxious carbon dioxide gases and acid rain, Venus actually is more Earth-like than Mars, said Esposito, a professor in CU-Boulder’s Laboratory for Atmospheric and Space Physics. A member of the Venus Monitoring Camera team for the $260 million now slated for launch from the Baikonur Cosmodrome in Kazakhstan on Nov. 9, Esposito said Venus is a “neglected planet” that undoubtedly harbors a number of astounding discoveries.

One question revolves around what is known as an “unknown ultraviolet absorber” high in the planet’s clouds that blocks sunlight from reaching the surface. “Some scientists believe there is the potential, at least, that life could be found in the clouds of Venus,” said Esposito. “There has been speculation that sunlight absorbed by the clouds might be involved in some kind of biological activity.”

Esposito is particularly eager to see if volcanoes on Venus are still active. In 1983 he used data from a CU-Boulder instrument that flew on NASA’s Pioneer Venus spacecraft to uncover evidence that a massive volcanic eruption there poured huge amounts of sulfur dioxide into the upper atmosphere. The eruption, which likely occurred in the late 1970s, appears to have been at least 10 times more powerful than any that have occurred on Earth in more than a century, he said.

“The spacecraft will be looking for ‘hotspots’ through the clouds in an attempt to make a positive detection of volcanoes,” said Esposito, who made the first observations of Venus with the Hubble Space Telescope in 1995. “While the Magellan mission that mapped Venus in the 1990s was not able to find evidence of volcanic activity, it did not close out the question. This will give us another shot.”

Since Venus and Earth were virtual twins at birth, scientists are puzzled how planets so similar in size, mass and composition could have evolved such different physical and chemical processes, he said. “The results from missions like this have major implications for our understanding of terrestrial planets as a whole, and for comparable processes occurring on Earth and Mars,” said Esposito.

Esposito has been involved in a number of planetary exploration missions at CU-Boulder. He currently is science team leader for the UltraViolet Imaging Spectrograph, a $12.5 million CU-Boulder instrument on the Cassini spacecraft now exploring the rings and moons of Saturn.

He also was an investigator for a CU-Boulder instrument that visited Jupiter and its moons in the 1990s aboard NASA’s Galileo spacecraft, and was an investigator for NASA’s Voyager 2 spacecraft that toted a CU-Boulder instrument on a tour of the solar system’s planets in the 1970s and 1980s.

Esposito was a science team member on two failed Russian missions to Mars — the 1988 Phobos mission that exploded in space and the Mars 96 mission that crashed in Earth’s ocean. Five of the science instruments on Venus Express are “spares” from the Mars Express and Rosetta comet mission, according to ESA.

In addition to the camera, the Venus Express spacecraft also is carrying two imaging spectrometers, a spectrometer to measure atmospheric constituents, a radio science experiment and a space plasma and atom-detecting instrument. The spacecraft is expected to arrive at Venus in April 2006 and orbit the planet for about 16 months.

The Venus Express mission originally was scheduled to launch Oct. 26, but a thermal-insulation problem discovered in the upper-stage booster rocket caused a two-week delay. The launch window closes on Nov. 24.

Original Source: UC Boulder News Release