Category Archives: Cool Stuff

The Long and Short of it

The Sun has reached the most northerly extent of the annual cycle of the seasons and will now begin the journey to the corresponding southernmost point.

In the north the daylight will begin to shorten and while it is called the start of summer, quite a few of us have been enjoying warmer temperatures for a while compared to earlier in the year. In the south of course the opposite is true.

The time of the June Solstice is (or was) 10:07 UTC, today 21 June 2018.

Thanks to TimeandDate.com for the image.

How About That!

The shot all night-time probably anyone who has spent any time taking pictures of the night sky hope for but seldom, if ever get. Planned shots are difficult enough to begin with but to take such a fabulous image, well balanced and composed, it’s simply amazing is what it is.

Congratulations and bravo Uwe Reichert. There is a great story behind the image also. Thank you ESA I enjoyed it very much:

Sometimes, nature is the best art director!

When Uwe Reichert grabbed his camera and tripod on the evening of 16 June 2018, he intended simply to image the conjunction of the then-three-day old Moon and the bright Venus.

In his backyard, near Heidelberg, Germany, trees and bushes blocked the view towards the western horizon, so he strolled through the neighbourhood searching for a better viewpoint. After taking a few pictures from various positions, he finally ended up on the outskirts of the town where he could see both celestial objects shining above some scattered clouds in the far distance.

He set the focal length of his 100-400mm telephoto lens to 180mm, chose a small aperture of f/10 so that bright Venus might produce some pictorial rays and switched the sensitivity to ISO 4000 to keep the exposure time short enough to avoid blurring due to Earth’s rotation. By cosmic chance, in the same instant that he pressed the button of the camera’s remote control, Reichert saw something bright falling from the sky.

First, a white light flashed up above Venus, moved downward with high speed, changing colour into an intense greenish glare, and what once appeared as one object disintegrated to a spray of smaller sparkles keeping the original trajectory until dying out just over the horizon.

As a long-time observer, both amateur and professional, he had seen many different celestial phenomena, including countless meteors and some bright fireballs, but this one appeared odd: The sparkles looked more like an exploding firework than a dying shooting star. But both the speed of the object and the very narrow angle under which the sparkles fanned out were arguments against artificial fireworks or other pyrotechnics.

Within a few seconds, Reichert went through different emotional states ranging from astonishment and puzzlement to euphoria: Had he really seen a cosmic body burning up in Earth’s atmosphere? When he checked the display of his camera, he was even more surprised: The object had crossed the camera’s field of view leaving a bright streak on the image. The streak appeared to have pierced the clouds as an object would have done when falling from high altitude down to Earth. Clearly, this object had really been falling down, but taking perspective into account the whole trajectory must have been above the clouds. Therefore, the flight path must have been much farther away than it appeared.

As it turned out a few hours later, with the help of Reichert’s picture, the fireball’s ground track was identified to have been over Belgium, some 230 kilometres away from the photographer’s position. Hundreds of people had seen the fireball, and the many sightings were also reported from Belgium and Holland, where Reichert’s picture made it to several news websites the next day.

Uwe Reichert is editor-in-chief at Sterne und Weltraum

Test Rover in Chile

Wow! I now have new desktop background. If you click the image you can see a larger version.

The original caption from NASA: The Moon begins to rise behind the ARADS rover during the 2017 season of field tests in Chile’s Atacama Desert. The Milky Way is visible in the night sky.

The Atacama Rover and Astrobiology Drilling Studies, or ARADS, project is designing tools and techniques that could be used to search for life one day on Mars or other places in the Solar System. The team’s prototype rover combines the ability to move across the surface, drill down to collect soil samples, and feed them to several life-detection instruments on board. The extreme conditions of Chile’s Atacama Desert provide one of the most Mars-like environments on Earth, where the team can test and refine these technologies and methods.

ARADS is led by NASA’s Ames Research Center in California’s Silicon Valley. Partners include NASA centers Goddard Space Flight Center in Greenbelt, Maryland, and the Jet Propulsion Laboratory in Pasadena, California, as well as Johns Hopkins University in Baltimore, Maryland, Honeybee Robotics in New York, the University of Antofagasta and CampoAlto SpA, both in Chile, and Spain’s Center for Astrobiology.

Credit: NASA/CampoAlto/Victor Robles

Our (distant) Future

NASA: An image of the galaxy Arp299B, which is undergoing a merging process with Arp299A (the galaxy to the left), captured by NASA’s Hubble space telescope. The inset features an artist’s illustration of a tidal disruption event (TDE), which occurs when a star passes fatally close to a supermassive black hole. A TDE was recently observed near the center of Arp299B.

Is this our future? Yes it or something approximating this will, it seems, will happen. The Milky Way and the Andromeda Galaxy will one day merge. Not to worry, it will be many millions of years in the future. Most galaxies are red-shifted, moving away from us; most but not all. Andromeda is blue-shifted meaning it is moving towards us.

Red-shifted? Blue-shifted? Ahh, the Doppler Effect.

Image: NRAO/AUI/NSF/NASA/STScI

CubeSat Plasma Thruster

Nice, it was only a matter of time.

ESA: This micro-pulsed plasma thruster has been designed for propulsion of miniature CubeSats; its first firing is seen here. The thruster works by pulsing a lightning-like electric arc between two electrodes. This vaporizes the thruster propellant into charged plasma, which is then accelerated in the electromagnetic field set up between the electrodes.

Developed for ESA by Mars Space Ltd and Clyde Space of the UK with Southampton University, this 2 Watt, 42 Newton-second impulse plasma thruster has been qualified for space, with more than a million firing pulses demonstrated during testing.

It has been designed for a range of uses, including drag compensation in low orbits, orbit maintenance, formation flying and small orbit transfers. The thruster could also serve as a CubeSat deorbiting device, gradually reducing orbital altitude until atmospheric re-entry is achieved.

About the size of a DVD reader, the thruster weighs just 280 grams including its propellant load and drive electronics.

An Isolated Neutron Star

Great image collaboration between two great observatories, Chandra and the VLT – Credits: X-ray (NASA/CXC/ESO/F.Vogt et al); Optical (ESO/VLT/MUSE & NASA/STScI. The circumstances surrounding the neutron star is very interesting.

NASA (Molly Porter) – Astronomers have discovered a special kind of neutron star for the first time outside of the Milky Way galaxy, using data from NASA’s Chandra X-ray Observatory and the European Southern Observatory’s Very Large Telescope (VLT) in Chile.

Neutron stars are the ultra dense cores of massive stars that collapse and undergo a supernova explosion. This newly identified neutron star is a rare variety that has both a low magnetic field and no stellar companion.

The neutron star is located within the remains of a supernova – known as 1E 0102.2-7219 (E0102 for short) – in the Small Magellanic Cloud, located 200,000 light years from Earth.

This new composite image of E0102 allows astronomers to learn new details about this object that was discovered more than three decades ago. In this image, X-rays from Chandra are blue and purple, and visible light data from VLT’s Multi Unit Spectroscopic Explorer (MUSE) instrument are bright red. Additional data from the Hubble Space Telescope are dark red and green.

Oxygen-rich supernova remnants like E0102 are important for understanding how massive stars fuse lighter elements into heavier ones before they explode. Seen up to a few thousand years after the original explosion, oxygen-rich remnants contain the debris ejected from the dead star’s interior. This debris (visible as a green filamentary structure in the combined image) is observed today hurtling through space after being expelled at millions of miles per hour.

Chandra observations of E0102 show that the supernova remnant is dominated by a large ring-shaped structure in X-rays, associated with the blast wave of the supernova. The new MUSE data revealed a smaller ring of gas (in bright red) that is expanding more slowly than the blast wave. At the center of this ring is a blue point-like source of X-rays. Together, the small ring and point source act like a celestial bull’s eye.

The combined Chandra and MUSE data suggest that this source is an isolated neutron star, created in the supernova explosion about two millennia ago. The X-ray energy signature, or “spectrum,” of this source is very similar to that of the neutron stars located at the center of two other famous oxygen-rich supernova remnants: Cassiopeia A (Cas A) and Puppis A. These two neutron stars also do not have companion stars.

The lack of evidence for extended radio emission or pulsed X-ray radiation, typically associated with rapidly rotating highly-magnetized neutron stars, indicates that the astronomers have detected the X-radiation from the hot surface of an isolated neutron star with low magnetic fields. About ten such objects have been detected in the Milky Way galaxy, but this is the first one detected outside our galaxy.

But how did this neutron star end up in its current position, seemingly offset from the center of the circular shell of X-ray emission produced by the blast wave of the supernova? One possibility is that the supernova explosion did occur near the middle of the remnant, but the neutron star was kicked away from the site in an asymmetric explosion, at a high speed of about two million miles per hour. However, in this scenario, it is difficult to explain why the neutron star is, today, so neatly encircled by the recently discovered ring of gas seen at optical wavelengths.

Another possible explanation is that the neutron star is moving slowly and its current position is roughly where the supernova explosion happened. In this case, the material in the optical ring may have been ejected either during the supernova explosion, or by the doomed progenitor star up to a few thousand years before.

A challenge for this second scenario is that the explosion site would be located well away from the center of the remnant as determined by the extended X-ray emission. This would imply a special set of circumstances for the surroundings of E0102: for example, a cavity carved by winds from the progenitor star before the supernova explosion, and variations in the density of the interstellar gas and dust surrounding the remnant.

Future observations of E0102 at X-ray, optical, and radio wavelengths should help astronomers solve this exciting new puzzle posed by the lonely neutron star.

A paper describing these results was published in the April issue of Nature Astronomy, and is available online. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra’s science and flight operations.