March comet comes to (low) northern skies

Image: Mid-March sky positions for Comet PANSTARRS. Credit: NASA
For those in search of comet L4 PANSTARRS, look to the west after sunset in early and mid-March. This graphic shows the comet’s expected positions in the sky. Image credit: NASA

Comets visible to the naked eye are a rare delicacy in the celestial smorgasbord of objects in the nighttime sky.  Scientists estimate that the opportunity to see one of these icy dirtballs advertising their cosmic presence so brilliantly they can be seen without the aid of a telescope or binoculars happens only once every five to 10 years.  That said, there may be two naked-eye comets available for your viewing pleasure this year.

“You might have heard of a comet ISON, which may become a spectacular naked-eye comet later this fall,” said Amy Mainzer, the principal investigator of NASA’s NEOWISE mission at the Jet Propulsion Laboratory (JPL) in Pasadena, Calif., and self-described cosmic icy dirtball fan.  “But if you have the right conditions you don’t have to wait for ISON. Within a few days, comet PANSTARRS will be making its appearance in the skies of the Northern Hemisphere just after twilight.”

Discovered in June 2011, comet 2011 L4 (PANSTARRS) bears the name of the telescopic survey that discovered it — the less than mellifluous sounding “Panoramic Survey Telescope and Rapid Response System” which sits atop the Haleakala volcano in Hawaii.

Since its discovery a year-and-a-half ago, observing comet PANSTARRS has been the exclusive dominion of comet aficionados in the Southern Hemisphere, but that is about to change.  As the comet continues its well-understood and safe passage through the inner solar system, its celestial splendor will be lost to those in the Southern Hemisphere, but found by those up north.

“There is a catch to viewing comet PANSTARRS,” said Mainzer. “This one is not that bright and is going to be low on the western horizon, so you’ll need a relatively unobstructed view to the southwest at twilight and, of course, some good comet-watching weather.”

Well, there is one more issue — the time of day, or night, to view it.

“Look too early and the sky will be too bright,” said Rachel Stevenson, a NASA Postdoctoral Fellow at JPL. “Look too late, the comet will be too low and obstructed by the horizon.  This comet has a relatively small window.”

By March 8, comet PANSTARRS may be viewable for those with a totally unobstructed view of the western horizon for about 15 minutes after twilight.  On March 10, it will make its closest approach to the sun about 28 million miles (45 million kilometers) away. As it continues its nightly trek across the sky, the comet may get lost in the sun’s glare but should return and be visible to the naked eye by March 12. As time marches on in the month of March, the comet will begin to fade away slowly, becoming difficult to view (even with binoculars or small telescopes) by month’s end.  The comet will appear as a bright point of light with its diffuse tail pointing nearly straight up from the horizon like an exclamation point.

What, if any, attraction does seeing a relatively dim naked-eye comet with the naked eye hold for someone who works with them every day, with file after file of high-resolution imagery spilling out on her computer workstation?

“You bet I’m going to go look at it!” said Mainzer. “Comet PANSTARRS may be a little bit of a challenge to find without a pair of binoculars, but there is something intimately satisfying to see it with your own two eyes.  If you have a good viewing spot and good weather, it will be like the Sword of Gryffindor, it should present itself to anyone who is worthy.”

NASA detects, tracks and characterizes asteroids and comets passing relatively close to Earth using both ground- and space-based telescopes. The Near-Earth Object Observations Program, commonly called “Spaceguard,” discovers these objects, characterizes a subset of them, and predicts their paths to determine if any could be potentially hazardous to our planet.

Article courtesy JPL

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Space station spotting service announced

Photo: Arc of the International Space Station passing through the Big Dipper. Credit: Chris Christie.
The ISS passed through the “Big Dipper” August 23, 2012. Photo by Chris Christie.

WASHINGTON — On the 12th anniversary of crews continuously living and working aboard the International Space Station, NASA announced a new service to help people see the orbiting laboratory when it passes overhead. “Spot the Station” will send an email or text message to those who sign up for the service a few hours before they will be able to see the space station.

Nov. 2 marked 12 years of continuous human habitation of the space station.

“It’s really remarkable to see the space station fly overhead and to realize humans built an orbital complex that can be spotted from Earth by almost anyone looking up at just the right moment,” said William Gerstenmaier, NASA’s associate administrator for human exploration and operations. “We’re accomplishing science on the space station that is helping to improve life on Earth and paving the way for future exploration of deep space.”

When the space station is visible — typically at dawn and dusk — it is the brightest object in the night sky, other than the moon. On a clear night, the station is visible as a fast moving point of light, similar in size and brightness to the planet Venus. “Spot the Station” users will have the options to receive alerts about morning, evening or both types of sightings.

The International Space Station’s trajectory passes over more than 90 percent of Earth’s population. The service is designed to only notify users of passes that are high enough in the sky to be easily visible over trees, buildings and other objects on the horizon. NASA’s Johnson Space Center calculates the sighting information several times a week for more than 4,600 locations worldwide, all of which are available on “Spot the Station.”

To sign up for “Spot the Station,” visit:
http://spotthestation.nasa.gov

For information about the International Space Station and a full list of sightings, visit:
http://www.nasa.gov/station

Source: NASA Press Release

Earth-sized planet discovered in Alpha Centauri system

European astronomers have discovered a planet with about the mass of the Earth orbiting a star in the Alpha Centauri system — the nearest to Earth. It is also the lightest exoplanet ever discovered around a star like the Sun. The planet was detected using the HARPS instrument on the 3.6-metre telescope at ESO’s La Silla Observatory in Chile. The results appeared online in the journal Nature on October 17, 2012.

Alpha Centauri is one of the brightest stars in the southern skies and is the nearest stellar system to our Solar System — only 4.3 light-years away. It is actually a triple star — a system consisting of two stars similar to the Sun orbiting close to each other, designated Alpha Centauri A and B, and a more distant and faint red component known as Proxima Centauri. Since the 19th century astronomers have speculated about planets orbiting these bodies, the closest possible abodes for life beyond the Solar System, but searches of increasing precision had revealed nothing. Until now.

“Our observations extended over more than four years using the HARPS instrument and have revealed a tiny, but real, signal from a planet orbiting Alpha Centauri B every 3.2 days,” says Xavier Dumusque (Geneva Observatory, Switzerland and Centro de Astrofisica da Universidade do Porto, Portugal), lead author of the paper. “It’s an extraordinary discovery and it has pushed our technique to the limit!”

The European team detected the planet by picking up the tiny wobbles in the motion of the star Alpha Centauri B created by the gravitational pull of the orbiting planet. The effect is minute — it causes the star to move back and forth by no more than 51 centimetres per second (1.8 km/hour), about the speed of a baby crawling. This is the highest precision ever achieved using this method.

Alpha Centauri B is very similar to the Sun but slightly smaller and less bright. The newly discovered planet, with a mass of a little more than that of the Earth, is orbiting about six million kilometres away from the star, much closer than Mercury is to the Sun in the Solar System. The orbit of the other bright component of the double star, Alpha Centauri A, keeps it hundreds of times further away, but it would still be a very brilliant object in the planet’s skies.

The first exoplanet around a Sun-like star was found by the same team back in 1995 and since then there have been more than 800 confirmed discoveries, but most are much bigger than the Earth, and many are as big as Jupiter. The challenge astronomers now face is to detect and characterise a planet of mass comparable to the Earth that is orbiting in the habitable zone around another star. The first step has now been taken.

“This is the first planet with a mass similar to Earth ever found around a star like the Sun. Its orbit is very close to its star and it must be much too hot for life as we know it,” adds Stéphane Udry (Geneva Observatory), a co-author of the paper and member of the team, “but it may well be just one planet in a system of several. Our other HARPS results, and new findings from Kepler, both show clearly that the majority of low-mass planets are found in such systems.”

Source: European Southern Observatory

Twilight scene: Orion, Venus, and the ISS

Photo: Long trail of the International Space Station in the evening sky. By Bruce Lane.
Trail of the International Space Station in the evening sky. Photo by Bruce Lane.

CAA member Bruce Lane photographed a portion of the International Space Station’s (ISS’s) trail as is passed through twilight skies over Northeastern Ohio. The April 12, 2012 pass put the ISS between the constellation Orion (left) and brilliant planet Venus (right). Wispy clouds decorated the darkening sky. Here’s what Bruce said of his photograph: “I took the … photo of last night’s ISS pass at 9:04:27. It was a nice pass that faded into the clouds as the ISS headed into … the east.” {This image shows the western sky with the ISS moving up, towards the upper-right of the frame.} Technical stuff: Tripod-mounted Canon Digital Rebel XT, ISO 200, 18 mm., 20 sec., f/3.5.

Mercury projects featured on stamps

Image: Postage stamps feature two "Mercury" projects. -- USPS
Two commemorative postage stamps issued by the US Postal Service feature two different "Mercury" projects. -- USPS Image

KENNEDY SPACE CENTER, FL — The Postal Service dedicated two stamps on May 4, 2011 commemorating two historic events — one that occurred a half century ago, and the second that’s making history now.

The 50th anniversary of America’s first manned spaceflight and an unmanned spacecraft currently charting planet Mercury were commemorated today on two 44-cent First-Class Forever stamps. The dedication ceremony took place next to a seven-story replica of the rocket Alan Shepard piloted to become America’s first man in space. A second stamp celebrates the MESSENGER Mission spacecraft that is currently orbiting and charting planet Mercury.

“These two historic missions — Shepard’s Mercury flight that took place 50 years ago tomorrow, and MESSENGER’s current orbiting of Mercury — frame a remarkable 50-year span in which America has advanced space exploration through more than 1,500 manned and unmanned flights,” said Stephen Masse, U.S. Postal Service vice president, finance and planning, in dedicating the stamps. “The Postal Service is proud to commemorate these achievements on stamps.”

Joining Masse in the dedication was Laura Shepard Churchley, Shepard’s daughter; Scott Carpenter, Mercury astronaut; Charles Bolden, NASA administrator and former Space Shuttle commander; Robert Cabana, former Space Shuttle commander and current director, Kennedy Space Center; and, Jim Adams, NASA deputy director, Planetary Science.

“These stamps, which will go out by the millions across this country, are a testament to the thousands of NASA men and women who shared dreams of human spaceflight and enlarging our knowledge of the universe,” said NASA Administrator Charles Bolden.

Project Mercury
As the world watched on television, Shepard blasted off from Cape Canaveral, Fla., on May 5, 1961. The flight reached a maximum speed of 5,100 mph, roughly eight times the speed of sound, and a zenith of 116 miles above the Earth. With parachutes deploying, the space capsule safely splashed down in the Atlantic some 300 miles from the launch site. The New York Times declared that Shepard’s 15-minute flight “roused the country to one of its highest peaks of exultation since the end of World War II.”

Emboldened by this achievement, President John F. Kennedy declared in a historic speech on May 25, 1961, that America “should commit itself to achieving the goal, before this decade is out, of landing a man on the moon and returning him safely to the Earth.”

The Mercury project set the country on a path that would lead to the stunning Apollo 11 moon landing eight years later on July 20, 1969, a crowning technological achievement of the 20th century. Shepard commanded the Apollo 14 mission, touching down on the moon February 5, 1971. He died of leukemia near his home in Pebble Beach, California on July 21, 1998.

MESSENGER
On March 17, 2011, MESSENGER became the first spacecraft to enter into orbit around Mercury. MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) is a scientific mission to investigate Mercury, which some scientists say is “the least-studied terrestrial planet” in our solar system.

Launched from Cape Canaveral Air Force Station, FL, on Aug. 3, 2004, the spacecraft made six “flybys” of planets, including one of Earth, two of Venus, and three of Mercury. The flybys were done to collect data, to conserve fuel through gravity assists, and to make adjustments critical to achieving the precise trajectory for successfully inserting the spacecraft into orbit around Mercury.

Entering orbit in March 2011 represented a major milestone in space exploration. The data obtained by MESSENGER before and during the year-long orbit will be analyzed for many years to come. Scientists think the data may explain how the planet took shape and also offer clues about the origin of the solar system.

Creating the Stamps
Donato Giancola of Brooklyn, NY, illustrated the stamps under the direction of Phil Jordan of Falls Church, VA, who based the artwork on NASA photographs and images. The phrase “Mercury Project,” depicted on the stamp image was approved by NASA officials who indicate the term is used interchangeably with “Project Mercury” as noted in the text on the back of the stamp sheet. The MESSENGER Mission stamp depicts the MESSENGER spacecraft orbiting Mercury.

The Project Mercury and MESSENGER Mission Stamps are being issued as Forever stamps. Forever stamps are always equal in value to the current First-Class Mail one-ounce rate.