The region surrounding the reflection nebula Messier 78

This image of the region surrounding the reflection nebula Messier 78, just to the north of Orion’s belt, shows clouds of cosmic dust threaded through the nebula like a string of pearls.

The submillimeter-wavelength observations, made with the Atacama Pathfinder Experiment (APEX) telescope and shown here in orange, use the heat glow of interstellar dust grains to show astronomers where new stars are being formed.

They are overlaid on a view of the region in visible light.

Image: ESO/APEX (MPIfR/ESO/OSO)/T. Stanke et al./Igor Chekalin/Digitized Sky Survey 2

NASA Juno: Jupiter-Bound Probe Changes Orbit in Deep Space

Juno, NASA's Jupiter-bound probe fired its main engine Thursday (Aug. 30) to help set up a speed-boosting flyby of Earth next year.

The engine burn — which took place when the Juno spacecraft was about 300 million miles (483 million kilometers) from Earth — began at 6:57 p.m. EDT (2257 GMT) Thursday and lasted nearly 30 minutes.

It appears to have worked according to plan, changing the probe's velocity by about 770 mph (1,240 kph), researchers said.

"This first and successful main engine burn is the payoff for a lot of hard work and planning by the operations team," Juno project manager Rick Nybakken, of NASA's Jet Propulsion Laboratory in Pasadena, Calif., said in a statement.

"We started detailed preparations for this maneuver earlier this year, and over the last five months we've been characterizing and configuring the spacecraft, primarily in the propulsion and thermal systems," he added.

After another burn this Tuesday (Sept. 4), Juno should be on course for its Earth flyby on Oct. 9, 2013, which will bring the probe within 310 miles (500 km) of our planet. Earth's gravity will give the spacecraft a big push, boosting its velocity by 16,330 mph (26,280 kph) and placing Juno on its final path to Jupiter, researchers said. Juno was launched on Aug. 5, 2011 and is slated to arrive at the solar system's largest planet on July 4, 2016. Once there, Juno will orbit Jupiter 33 times from pole to pole, using its eight science instruments to peer beneath the gas giant's thick clouds. (The spacecraft takes its name from the goddess Juno, who was able to see through the clouds devised by her husband Jupiter in an attempt to hide his mischief.) The main goal of the $1.1 billion mission is to learn about Jupiter's atmosphere, magnetosphere, composition and origins, and to determine if the planet has a solid core, researchers said.

Star Trek Warp Drives: Slowing Down is a Planet Killer

Fans of science fiction will have one less technology to look forward to in the future.

The ubiquitous warp drive made popular in such shows as Star Trek, could fry any planetary system it stops in.

Faster than light technology (FLT) has been a dream for many sc-fi fans and even scientists who want an easy way to travel the vast distances in space.

Warp drives also solves the problem of relativity where the brave interstellar travelers can explore galaxies without their families back on Earth ageing a hundred years.

While Star Trek's warp drive is still purely a product of Hollywood imagination there are some concepts in physics that explore FTL.

One of those concepts is the Alcubierre warp drive proposed by Mexican theoretical physicist Miguel Alcubierre in 1994.

Basically the Alcubierre warp drive proposes that a ship would be propelled to faster than light speeds by creating a bubble of negative energy around it. Spacetime is compressed in front of the bubble and expanded behind it.

The ship would ride the bubble cruising at faster than light speeds while inside the bubble no faster than light prohibition is broken.

As enticing as the Alcubierre warp drive is or any other means for travelling faster than light, there is still the problem of stopping and stopping an FTL ship is going to wreak havoc on anyone unlucky enough to be in the ship's way.

According to Brendan McMonigal, Prof Geraint Lewis and Prof Philip O'Byrne of the University of Sydney, Alcubierre didn't take into consideration that many types of cosmic particles that the warp drive spaceship would encounter on its travels.

The research team found that these particles can get swept up in the warp bubble and after the ship decelerates from superluminal speed, the particles can get released in energetic outbursts strong enough to destroy anyone at the destination in front of the ship.

"Any people at the destination," the team's paper concludes, "would be gamma ray and high energy particle blasted into oblivion due to the extreme blueshifts for forward region particles."

One piece of good news that the team did find out is that while the warp drive is beyond human technology at the moment the theory behind the Alcubierre drive makes this possible in the future.

"Einstein's General Relativity tells us that gravity is the result of warped spacetime," McMonigal told the Register. "This means that simply by being in the gravitational field of the Earth as we are now, we are experiencing warped spacetime.

"What the warp drive equations tell us is what distribution of "stuff" we would need to create the spacetime deformation which would result in a ship travelling to a distant location in a short amount of time. In fact, the question of how we would generate this distribution is the main barrier to this technology."

In other words the drive is possible but researchers will have to figure how to stop the destination of the ship from disintegrating upon arrival.

Planets smashed into dust near supermassive black holes

Collisions between these rocky objects would occur at colossal speeds as large as 1000 km per second, continuously shattering and fragmenting the objects, until eventually they end up as microscopic dust.

Fat doughnut-shaped dust shrouds that obscure about half of supermassive black holes could be the result of high speed crashes between planets and asteroids, according to a new theory from an international team of astronomers.

The scientists, led by Dr. Sergei Nayakshin of the University of Leicester, publish their results in the journal Monthly Notices of the Royal Astronomical Society.

Supermassive black holes reside in the central parts of most galaxies. Observations indicate that about 50% of them are hidden from view by mysterious clouds of dust, the origin of which is not completely understood.

The new theory is inspired by our own Solar System, where the so-called zodiacal dust is known to originate from collisions between solid bodies such as asteroids and comets.

The scientists propose that the central regions of galaxies contain not only black holes and stars but also planets and asteroids.

Collisions between these rocky objects would occur at colossal speeds as large as 1000 km per second, continuously shattering and fragmenting the objects, until eventually they end up as microscopic dust.

Dr. Nayakshin points out that this harsh environment - radiation and frequent collisions - would make the planets orbiting supermassive black holes sterile, even before they are destroyed.

"Too bad for life on these planets", he says, "but on the other hand the dust created in this way blocks much of the harmful radiation from reaching the rest of the host galaxy. This in turn may make it easier for life to prosper elsewhere in the rest of the central region of the galaxy."

He also believes that understanding the origin of the dust near black holes is important in our models of how these monsters grow and how exactly they affect their host galaxies.

"We suspect that the supermassive black hole in our own Galaxy, the Milky Way, expelled most of the gas that would otherwise turn into more stars and planets", he continues, "Understanding the origin of the dust in the inner regions of galaxies would take us one step closer to solving the mystery of the supermassive black holes".

ESA Mercury Planetary Orbiter: simulated trip to Mercury

The Structural and Thermal Model (STM) of the BepiColombo Mercury Planetary Orbiter (MPO) in the Large Space Simulator (LSS) at ESA's Test Centre in Noordwijk, the Netherlands. 

The MPO is mounted on the LSS gimbal stand / spin box and levelling table that support, orient, rotate and level the spacecraft during testing. 

The MPO is being prepared for thermal-balance testing. Copyright: ESA/Anneke Le'Floch.

Thermal-balance testing of the BepiColombo Mercury Planetary Orbiter Structural and Thermal Model, which has been under way in ESA's Large Space Simulator since 20 September, has been successfully completed.

During these tests the conditions the spacecraft will encounter during the cruise to Mercury and while in orbit have been simulated, and a number of tests to characterise the spacecraft performance under some worst-case scenarios have been carried out.

'Dry run' in the Large Space Simulator
Following the installation of the Mercury Planetary Orbiter (MPO) Structural and Thermal Model (STM) in the Large Space Simulator (LSS) at ESA's Test Centre in Noordwijk, the Netherlands on 31 August and the completion of all the necessary preparations, a 'dry run' was conducted on 13 September to verify the performance of the spacecraft, its instrumentation, and the gimbal stand / spin box and levelling table that support, orient, rotate and level the spacecraft during testing.

The dry run was performed with the LSS top cover open; the MPO was illuminated with just one of the nineteen 25-kW lamps that make up the solar simulator.

To reach the radiation intensity that the orbiter will experience in orbit around Mercury, the 121 hexagonal mirror segments that produce the beam have been adjusted to produce a converging beam rather than the standard parallel beam.

To allow the wall of the LSS to cope with the increased beam intensity while continuing to simulate the cold of space, an additional shroud has been installed.

Pump down and cold calibration
After the dry run, the LSS top hatch was closed and vacuum pumping commenced on 20 September.

Once a vacuum of around 10-5 mbar had been achieved, liquid nitrogen started to be pumped through the shrouds of the chamber walls to cool the interior of the LSS down to less than -173 degrees C (100 K).

Once cool-down was completed, the steady state under cold conditions (referred to as 'cold calibration') was achieved and baseline data were acquired.

Cruise and orbit
On 22 September, simulation of the initial cruise phase of MPO's journey to Mercury began.

This was followed, the next day, by the intermediate cruise phase; testing under in-orbit conditions followed, beginning on 26 September with conditions at aphelion and then moving on to perihelion.

Particular attention has been paid to conditions at perihelion, where the MPO will be most strongly illuminated.

Investigations of the spacecraft's thermal performance during entry into and exit from eclipse have also been also carried out through 'snapshots' at various attitudes (for example, rotation of 45 degrees with the Sun on the +Y/-X faces and tilting of 30 degrees with the Sun on the +Z/+Y faces).

Around 4000 litres of liquid nitrogen are consumed per hour during testing, so a steady stream of tankers have been arriving to replenish the 100 000-litre on-site storage capacity.

The heaters that simulate the thermal dissipation of the electronics units and those that warm critical components during eclipse are powered by external power sources during testing.

Temperature data, obtained using thermocouples, are acquired by the thermal data handling system that is part of the LSS.

Two infrared cameras are used to monitor the spacecraft's multi-layer insulation and items external to the satellite that face the Sun simulator.

To maintain realistic conditions for the heat pipe network, which is designed to work in the microgravity of Mercury orbit, the satellite is kept levelled by adjusting the levelling table and acquiring readings from on-board tilt meters.

Non-nominal attitude - testing the worst-case scenario

NASA: Avoiding Planetary Asteroid Hits Is A Big Job

Avoiding Planetary Hits Is A Big Job

The Scope of the Hazard
Near-Earth objects are asteroids and comets that orbit the Sun and approach or cross Earth's orbit. An asteroid or comet about 10 kilometers in diameter struck the Yucatan peninsula 65 million years ago and caused global devastation, probably wiping out large numbers of plant and animal species including the dinosaurs. Objects as large as this one strike Earth only about once every 100 million years on average, the report notes.

NASA has been highly successful at detecting and tracking objects 1 kilometer in diameter or larger, and continues to search for these large objects. Objects down to sizes of about 140 meters in diameter - which NASA has been mandated to survey for - would cause regional damage; such impacts happen on average every 30,000 years, the report says.

While impacts by large NEOs are rare, a single impact could inflict extreme damage, raising the classic problem of how to confront a possibility that is both very rare and very important. Far more likely are those impacts that cause only moderate damage and few fatalities.

Conducting surveys for NEOs and detailed studies of ways to mitigate collisions is best viewed as a form of insurance, the report says. How much to spend on these insurance premiums is a decision that must be made by the nation's policymakers.