Other stars show tails that trail behind them like a comet’s tail. Scientists used NASA’s Interstellar Boundary Explorer to confirm that our solar system has one too. From top left and going counter clockwise, the stars shown are: LLOrionis; BZ Cam; and Mira. Image Credit: NASA/HST/R.Casalegno/GALEX
FROM STEVE KLEYN
Mars rover 10th anniversary 1 July:
When NASA’s Mars rover Opportunity blasted off from Cape Canaveral in 2003, many onlookers expected a relatively short mission. Landing on Mars is risky business. The Red Planet has a long history of destroying spacecraft that attempt to visit it. Even if Opportunity did land safely, it was only designed for a 3-month mission on the hostile Martian surface. Few, if any, imagined that Opportunity would still be roving the red sands of Mars–and still making discoveries–ten years later.
On 7 July 2013, Opportunity celebrates the 10th anniversary of its launch and more than 9 years on Mars. Opportunity is celebrating by driving. The rover is currently en route to ‘Solander Point’, a place on the rim of Endurance Crater where a treasure-trove of geological layers is exposed for investigation.
Opportunity recently set the US space program’s all-time record for mileage on another planet. The milestone occurred on 15 May 2013, when the rover drove 80 metres, bringing its total odometry 35.760 kilometres or 22.220 miles. The previous mark had been held by the Apollo 17 moon rover, which astronauts Gene Cernan and Harrison Schmitt drove for 35.74 km (22.21 miles) across the lunar surface in December 1972.
Over the years, Opportunity’s travels have been punctuated by hundreds of stops to photograph and sample the Martian landscape. The surface of Mars of today is bone dry and hostile to life as we know it. Opportunity’s mission is to hunt for places where it wasn’t always so, places where ancient water might have nourished life forms native to Mars.
So far so good; the rover has found abundant evidence that liquid water was once present. For the past 20 months, Opportunity has been “working” the rim of Endeavour Crater. There, Opportunity found deposits of gypsum probably formed from groundwater seeping up through cracks in Martian soil. Also, Opportunity has also found signs of clay minerals in a rock named ‘Esperance’.
Solander Point, where Opportunity is heading now, has two key attractions. For one thing, while Opportunity’s most recent stop, Cape York, exposed just a few meters of geological layering, Solander Point exposes roughly 10 times as much. A visit to Solander Point will be like reading a Martian history book.
Second, and perhaps more importantly, there are north-facing slopes at Solander Point where the rover can tilt its solar panels toward the Sun and ride out the coming winter. The minimum-sunshine days of this sixth Martian winter for Opportunity will come in February 2014.
If Opportunity survives another year–and who now would bet against it?–the rover might yet break the all-time extraterrestrial driving record set by Lunokhod 2, a Soviet robotic vehicle that traveled an estimated 26 miles (42 km) across the Moon in 1973. After that lies the 26.2 mile mark. In other words, stay tuned for the first Martian Marathon.
To follow Opportunity and other rovers on Mars, please visit http://marsrovers.jpl.nasa.gov/
Source: Author: Dr. Tony Phillips Credit: Science@NASA
Hubble spots azure blue planet 11July:
Astronomers using the NASA/ESA Hubble Space Telescope have, for the first time, determined the true colour of a planet orbiting another star. If seen up close this planet, known as HD 189733b, would be a deep azure blue, reminiscent of Earth’s colour as seen from space. However, that’s where the similarities end. This ‘deep blue dot’ is a huge gas giant orbiting very close to its host star. The planet’s atmosphere is scorching with a temperature of over 1000 degrees Celsius, and it rains glass, sideways, in howling 7000 kilometre-per-hour winds.
NASA spacecraft maps the solar system’s tail 10 July:
Like a comet, the solar system has a tail. NASA’s Interstellar Boundary Explorer (IBEX) has for the first time mapped out the structure of this tail, which is shaped like a four-leaf clover. Scientists describe the tail, called the heliotail, based on the first three years of IBEX imagery in a paper published in the July 10 edition of the Astrophysical Journal.
While telescopes have spotted such tails around other stars, it has been difficult to see whether our star produced one. The particles found in the tail — and throughout the entire heliosphere, the region of space influenced by our Sun — do not shine, so they cannot be seen with conventional instruments.
“By examining the neutral atoms, IBEX has made the first observations of the heliotail,” said David McComas, IBEX principal investigator at Southwest Research Institute in San Antonio, Texas, and the paper’s lead author. “Many models have suggested the heliotail might look like this or like that, but we have had no observations. We always drew pictures where the tail of the solar system just trailed off the page, since we couldn’t even speculate about what it really looked like.”
IBEX measures the neutral particles created by collisions at the solar system’s boundaries. This technique, called energetic neutral atom imaging, relies on the fact that the paths of neutral particles are not affected by the solar magnetic field. Instead, the particles travel in a straight line from collision to IBEX. Consequently, observing where the neutral particles came from describes what is going on in these distant regions.
“Since first light in 2008, the IBEX mission team has amazed us with its discoveries at the interstellar boundary, including a previously unknown ribbon of energetic neutral particles stretching across it,” said Arik Posner, NASA’s IBEX program scientist in Washington. “The new IBEX image of the heliotail fills in a previously blank area on the map. We are first-hand witnesses of rapid progress in heliophysics science.”
By combining observations from the first three years of IBEX imagery, the team showed a tail with a combination of fast and slow moving particles. There are two lobes of slower particles on the sides and faster particles above and below. This four-leaf clover shape can be attributed to the fact that the Sun has been sending out fast solar wind near its poles and slower wind near its equator for the last few years. This is a common pattern in the most recent phase of the sun’s 11-year activity cycle.
The clover shape does not align perfectly with the solar system, however. The entire shape is rotated slightly, indicating that as it moves further away from the Sun and its magnetic influence, the charged particles begin to be nudged into a new orientation, aligning with the magnetic fields from the local galaxy.
Scientists do not know how long the tail is, but think that it eventually fades away and becomes indistinguishable from the rest of interstellar space. They are testing their current computer simulations of the solar system against the new observations to improve our understanding of the comet-like tail streaming out behind us.
For more information about the IBEX mission, visit: http://www.nasa.gov/ibex
Source: Author: Dr. Tony Phillips | Credit: Science@NASA