Sometimes I complain about the earthly weather, but mostly I like to post about astronomy and space events. Hope you enjoy the articles.
By: Susie77, 12:21 PM GMT on August 25, 2010
From: Science at NASA
The Mutating Mars Hoax
August 25, 2010: It spreads, it mutates, it refuses to die.
For the seventh year in a row, the Mars Hoax is infecting email boxes around the world. Passed from one reader to another, the message states that on August 27th Mars will approach Earth and swell to the size of a full Moon. "NO ONE ALIVE TODAY WILL EVER SEE THIS AGAIN," the email declares--always in caps.
News flash: It's not true.
Here are the facts. On August 27, 2010, Mars will be 314 million km from Earth, about as far away as it can get. Mars will shine in the western sky after sunset like a tiny red star of ordinary brightness. If you didn't know it was there, you probably wouldn't notice.
The only way to see Mars as large as the full Moon is to board a spaceship.
The origins of the Hoax can be traced back to 2003 when Mars really did swell to unusual proportions. On August 27th of that year, Mars came within 56 million km of Earth—the nearest it has been in 60,000 years. People marveled at the orange brilliance of Mars in the night sky and crowded around telescopes for clear views of the planet's towering volcanoes, ruddy plains and glistening polar ice caps. At the height of the display, Mars was about 75 times smaller than the full Moon.
That's when "the virus" was born.
Someone, somewhere, reasoned as follows: If Mars is 75 times smaller than the Moon, then magnifying it 75 times should make it equal to the Moon. Early versions of the Hoax encouraged readers to get out their telescopes and insert a 75x eyepiece: "At a modest 75 times magnification," the message stated, "Mars will look as big as the full Moon to the naked eye."
Soon, the Hoax was vectoring around the internet, making copies of itself and mutating. Advanced versions of the virus, sleeker and less wordy than its ancestors, omitted the magnification and simply stated, "Mars will look as big as the full Moon to the naked eye!" Before long, the year was omitted, too. August 27, 2003, became August 27, and the Hoax became immortal. Indeed, years of stories contradicting the Hoax have failed to stamp it out. This is the fourth vaccination by Science@NASA alone.
Tolerant readers point out that the Mars Hoax is not really a hoax, because it is not an intentional trick. The original composer probably believed everything he or she wrote in the message. If so, even the name of the Mars Hoax is wrong!
Here's what you should do on August 27th. Go outside at sunset and face west. The bright light you see shining through the twilight is lovely Venus. Grab a pair of binoculars and scan the sky around Venus. A few degrees to the right, you'll come across a little orange star-like object. That is Mars.
Now go back inside and delete that email.
By: Susie77, 11:24 AM GMT on August 22, 2010
Jack Horkheimer, director of Miami's planetarium and creator of PBS's "Star Gazer" program, went home to the stars on Friday, 20 August 2010.
By: Susie77, 11:37 PM GMT on August 19, 2010
I can't wait to have a glimpse of this alien world in our neighborhood.
From: Dawn comes to Vesta
Countdown to Vesta
August 19, 2010: Let the countdown begin. NASA's Dawn spacecraft is less than one year away from giant asteroid Vesta.
"There's nothing more exciting than revealing an unexplored, alien world," says Marc Rayman, Dawn's chief engineer at the Jet Propulsion Laboratory. "Vesta," he predicts, "is going to amaze us."
Dawn is slated to enter orbit around Vesta in late July 2011. As the first breathtaking images are beamed back to Earth, researchers will quickly combine them into a movie, allowing us all to ride along.
"It will look as though the spacecraft is hovering in one place while Vesta rotates beneath it," says Rayman.
Previous missions have shown us a handful of asteroids, but none as large as this hulking relic of the early solar system. Measuring 350 miles across and containing almost 10% of the mass of the entire asteroid belt, Vesta is a world unto itself.
"It's a big, rocky, terrestrial type body – more likely similar to the moon and Mercury than to the little chips of rocks we've flown by in the past," continues Rayman. "For example, there's a large crater at Vesta's south pole, and inside the crater is a mountain bigger than asteroid Eros."
Video (narrated by Leonard Nimoy)
Dawn will orbit Vesta for a year, conducting a detailed study and becoming the first spacecraft to ever orbit a body in the asteroid belt. Later, Dawn will leave Vesta and go on to orbit a second exotic world, dwarf planet Ceres--but that's another story.
Many scientists consider Vesta a protoplanet. The asteroid was in the process of forming into a full fledged planet when Jupiter interrupted its growth. The gas giant became so massive that its gravity stirred up the material in the asteroid belt so the objects there could no longer coalesce.
"Vesta can teach us a lot about how planets formed," says Christopher Russell of UCLA, the mission's Principal Investigator. "There is a whole team of scientists sitting on the edge of their seats waiting for that first glimpse of Vesta."
Dawn's official Vestian approach, which Rayman also calls the "oh man this is so cool phase" of the mission, begins next May. Unlike most orbital insertions, however, this one will be comparatively relaxing.
"This may be the first planetary mission that doesn't cause its mission team members to bite their nails while their spacecraft is getting into planetary orbit," says Rayman.
Countdown to Vesta (Vesta, 200px)
This fuzzy picture of Vesta (courtesy Hubble) will come into sharp focus when Dawn arrives in 2011. [more]
A conventional spacecraft's entry into a flight path around a celestial body is accompanied by crucial periods during which maneuvers must be executed with pinpoint precision. If anything goes wrong, all can be lost. But Dawn, with its gentle ion propulsion, slowly spirals in to its target, getting closer and closer as it loops around.
"Dawn's entire thrust profile for its long interplanetary flight has been devoted largely to the gradual reshaping of its orbit around the Sun so that by the time the spacecraft is in the vicinity of Vesta, its orbit will be very much like Vesta's."
With just a slight change in trajectory, the spacecraft will allow itself to be captured by Vesta's gravity.
"Even that gentle ion thrust will be quite sufficient to let the craft slip into orbit. It's like merging into traffic on an interstate – only gradual acceleration is needed. Dawn won't even notice the difference, but it will be in orbit around its first celestial target."
Dawn's first survey orbits will be high and leisurely, taking days to loop around Vesta at altitudes of about 1700 miles. After collecting a rich bounty of pictures and data from high altitude, Dawn will resume thrusting, spiraling down to lower and lower orbits, eventually settling in a little more than 100 miles high--lower than satellites orbiting Earth.
Parts of the surface may be reminiscent of features on Earth or the Moon with craters and perhaps even volcanoes.
"We don't expect to see active volcanoes," notes Carol Raymond, the mission's Deputy Principal Investigator at JPL, "but there could be ancient volcanic features still recognizable among the craters."
Meanwhile, "other sights could be completely unlike anything we've imagined," says Rayman. "It'll be pure excitement!"
By: Susie77, 1:58 PM GMT on August 19, 2010
Hope you all got to get out and see them this year. Gallery of wonderful photos:
By: Susie77, 8:46 PM GMT on August 05, 2010
From Science at NASA
Planets Align for the Perseid Meteor Shower
August 5, 2010: You know it's a good night when a beautiful alignment of planets is the second best thing that's going to happen.
Thursday, August 12th, is such a night.
The show begins at sundown when Venus, Saturn, Mars and the crescent Moon pop out of the western twilight in tight conjunction. All four heavenly objects will fit within a circle about 10 degrees in diameter, beaming together through the dusky colors of sunset. No telescope is required to enjoy this naked-eye event.
Perseids 2010 (Perseid sky map)
Looking northeast around midnight on August 12th-13th. The red dot is the Perseid radiant. Although Perseid meteors can appear in any part of the sky, all of their tails will point back to the radiant.
The planets will hang together in the western sky until 10 pm or so. When they leave, following the sun below the horizon, you should stay, because that is when the Perseid meteor shower begins. From 10 pm until dawn, meteors will flit across the starry sky in a display that's even more exciting than a planetary get-together.
The Perseid meteor shower is caused by debris from Comet Swift-Tuttle. Every 133 years the huge comet swings through the inner solar system and leaves behind a trail of dust and gravel. When Earth passes through the debris, specks of comet-stuff hit the atmosphere at 140,000 mph and disintegrate in flashes of light. These meteors are called Perseids because they fly out of the constellation Perseus.
Swift-Tuttle's debris zone is so wide, Earth spends weeks inside it. Indeed, we are in the outskirts now, and sky watchers are already reporting a trickle of late-night Perseids. The trickle could turn into a torrent between August 11th and 13th when Earth passes through the heart of the debris trail.
2010 is a good year for Perseids because the Moon won't be up during the midnight-to-dawn hours of greatest activity. Lunar glare can wipe out a good meteor shower, but that won't be the case this time.
As Perseus rises and the night deepens, meteor rates will increase. For sheer numbers, the best time to look is during the darkest hours before dawn on Friday morning, Aug. 13th, when most observers will see dozens of Perseids per hour.
For best results, get away from city lights. The darkness of the countryside multiplies the visible meteor rate 3- to 10-fold. A good dark sky will even improve the planetary alignment, allowing faint Mars and Saturn to make their full contribution to the display. Many families plan camping trips to coincide with the Perseids. The Milky Way arching over a mountain campground provides the perfect backdrop for a meteor shower.
Enjoy the show!
By: Susie77, 12:11 AM GMT on August 04, 2010
MIDDLE LATITUDE AURORAL ACTIVITY WARNING
Issued: 00:00 UTC, 04 August 2010
Solar Terrestrial Dispatch
VALID BEGINNING AT: EFFECTIVE IMMEDIATELY
VALID UNTIL: 23:00 UTC (7 pm EDT) ON 04 AUGUST 2010
PREDICTED IMPACT TIME OF DISTURBANCE: IN-PROGRESS
HIGH RISK PERIOD: 04 AUGUST
MODERATE RISK PERIOD: 04 - 05 AUGUST
PREDICTED ACTIVITY INDICES: 35, 20, 10, 10 (04 - 07 AUGUST)
POTENTIAL MAGNITUDE OF MIDDLE LATITUDE AURORAL ACTIVITY: MODERATE
POTENTIAL DURATION OF THIS ACTIVITY: MAIN BELT = 12 TO 24 HOURS
MINOR BELT = 18 TO 36 HOURS
ESTIMATED OPTIMUM OBSERVING CONDITIONS: PRIOR TO / NEAR LOCAL MIDNIGHT
EXPECTED LUNAR INTERFERENCE: MODERATE
OVERALL OPPORTUNITY FOR OBSERVATIONS FROM MIDDLE LATITUDES: FAIR
AURORAL ACTIVITY *MAY* BE OBSERVED APPROXIMATELY NORTH OF A LINE FROM...
SOUTHERN BRITISH COLUMBIA TO EXTREME NORTHERN IDAHO TO NORTHERN
MONTANA TO NORTH DAKOTA TO DARK-SKY SITES OF MINNESOTA TO NORTHERN
WISCONSIN TO NORTHERN MICHIGAN TO NORTHERN NEW YORK STATE TO MAINE.
ACTIVITY *MAY* ALSO BE OBSERVED APPROXIMATELY NORTH OF A LINE FROM...
EXTREME NORTHERN SCOTLAND TO FINLAND TO SWEDEN TO NORTHERN RUSSIA.
ACTIVITY *MAY* ALSO BE OBSERVED APPROXIMATELY SOUTH OF A LINE FROM...
EXTREME SOUTHERN NEW ZEALAND.
A coronal mass ejection has impacted the Earth and is producing
periods of minor to major geomagnetic storming. One location in the low
latitudes reported a period of severe geomagnetic storming, although that
appears to be a relatively isolated event that occurred shortly after the
disturbance arrived. We expect auroral activity to reach levels capable
being observed over fairly widespread mid-latitude locations during the
next 12 hours. Activity may persist through the next 24 to 36 hours, but
the strongest phase of activity will be observed during the next 12
The disturbance should begin to wane later on 4 August.
This warning will remain valid through 23:00 UTC (7 pm EDT) on 04
August. It will then be updated or allowed to expire. For updated
information, visit: http://www.spacew.com/forum. For real-time
plots of current activity, visit: http://www.spacew.com/plots.html.
PLEASE REPORT OBSERVATIONS OF AURORAL ACTIVITY TO: