Category Archives: ESA

Polaris Flare

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From ESA and the Planck Collaboration:

This image from ESA’s Planck satellite appears to show something quite ethereal and fantastical: a sprite-like figure emerging from scorching flames and walking towards the left of the frame, its silhouette a blaze of warm-hued colours.

This fiery illusion is actually a celestial feature named the Polaris Flare. This name is somewhat misleading; despite its moniker, the Polaris Flare is not a flare but a 10 light-year-wide bundle of dusty filaments in the constellation of Ursa Minor (The Little Bear), some 500 light-years away.

The Polaris Flare is located near the North Celestial Pole, a perceived point in the sky aligned with Earth’s spin axis. Extended into the skies of the northern and southern hemispheres, this imaginary line points to the two celestial poles. To find the North Celestial Pole, an observer need only locate the nearby Polaris (otherwise known as the North Star or Pole Star), the brightest star in the constellation of Ursa Minor.

Some of the secrets of the Polaris Flare were uncovered when it was observed by ESA’s Herschel some years ago. Using a combination of such Herschel observations and a computer simulation, scientists think that the Polaris Flare filaments could have been formed as a result of slow shockwaves pushing their way through a dense interstellar cloud, an accumulation of cold cosmic dust and gas sitting between the stars of our Galaxy.

These shockwaves, reminiscent of the sonic booms formed by fast sound waves here on Earth, would have been themselves triggered by nearby exploding stars that disrupted their surroundings as they died, triggering cloud-wide waves of turbulence

These shockwaves, reminiscent of the sonic booms formed by fast sound waves here on Earth, were themselves triggered by nearby exploding stars that disrupted their surroundings as they died, triggering cloud-wide waves of turbulence. These waves swept up the gas and dust in their path, sculpting the material into the snaking filaments we see.

This image is not a true-colour view, nor is it an artistic impression of the Flare, rather it comprises observations from Planck, which operated between 2009 and 2013. Planck scanned and mapped the entire sky, including the plane of the Milky Way, looking for signs of ancient light (known as the cosmic microwave background) and cosmic dust emission. This dust emission allowed Planck to create this unique map of the sky – a magnetic map.

The relief lines laced across this image show the average direction of our Galaxy’s magnetic field in the region containing the Polaris Flare. This was created using the observed emission from cosmic dust, which was polarised (constrained to one direction). Dust grains in and around the Milky Way are affected by and interlaced with the Galaxy’s magnetic field, causing them to align preferentially in space. This carries through to the dust’s emission, which also displays a preferential orientation that Planck could detect.

The emission from dust is computed from a combination of Planck observations at 353, 545 and 857 GHz, whereas the direction of the magnetic field is based on Planck polarisation data at 353 GHz. This frame has an area of 30 x 30º on the sky, and the colours represent the intensity of dust emission.

The Orbits of Rosetta

ESA gives us this visualization of Rosetta’s journey. The video gives us a pretty good sense of the journey and how exacting the planning was and what it will be in the future, although the final bits of the journey were not completely finalized until after this visualization was made.

The trajectory shown in this animation is created from real data, but the comet rotation is not. An arrow indicates the direction to the Sun as the camera viewpoint changes during the animation. — ESA

I am always am amazed how ESA can make the very difficult look easy.

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Hubble’s Fireball

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WOW! Thanks to ESA/Hubble & NASA Acknowledgement: J. Schmidt (geckzilla.com) for this image.

A higher resolution version is available from ESA.  Links go off-site so you will have to back track.

From the ESA press release (linked above):
This dramatic burst of colour shows a cosmic object with an equally dramatic history. Enveloped within striking, billowing clouds of gas and dust that form a nebula known as M1-67, sits a bright star named Hen 2-427 (otherwise known as WR 124).

This star is just as intense as the scene unfolding around it. It is a Wolf-Rayet star, a rare type of star known to have very high surface temperatures – well over 25000ºC, next to the Sun’s comparatively cool 5500ºC – and enormous mass, which ranges over 5–20 times our Sun’s. Such stars are constantly losing vast amounts of mass via thick winds that continuously pour from their surfaces out into space.

Hen 2-427 is responsible for creating the entire scene shown here, which has been captured in beautiful detail by the NASA/ESA Hubble Space Telescope. The star, thought to be a massive one in the later stages of its evolution, blasted the material comprising M1-67 out into space some 10 millennia ago – perhaps in multiple outbursts – to form an expanding ring of ejecta.

Since then, the star has continued to flood the nebula with massive clumps of gas and intense ionising radiation via its fierce stellar winds, shaping and sculpting its evolution. M1-67 is roughly ring-shaped but lacks a clear structure – it is essentially a collection of large, massive, superheated knots of gas all clustered around a central star.

Hen 2-427 and M1-67 lie 15 000 light-years away in the constellation of Sagitta (The Arrow). This image uses visible-light data gathered by Hubble’s Wide Field Planetary Camera 2, and was released in 2015 (the same data were previously processed and released in 1998).

Quasars Help Navigating to Mars

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How is ESA going to navigate to Mars?  By using quasars of course.

Very cool!!! The inset is explained below BTW.

Image and caption below: Copyright Estrack / ESA/D. Pazos – Quasar P1514-24 inset image: Rami Rekola, Univerity of Turku, 2001

From ESA:

  • In order to precisely deliver the Schiaparelli landing demonstrator module to the martian surface and then insert ExoMars/TGO into orbit around the Red Planet, it’s necessary to pin down the spacecraft’s location to within just a few hundred metres at a distance of more than 150 million km.To achieve this amazing level of accuracy, ESA experts are making use of ‘quasars’ – the most luminous objects in the Universe – as ‘calibrators’ in a technique known as Delta-Differential One-Way Ranging, or delta-DOR.Until recently, quasars were only poorly understood. These objects can emit 1000 times the energy of our entire Milky Way galaxy from a volume that it not much bigger than our Solar System, making them fearfully powerful.
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Venus Express Science

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We a bit more science from Venus and the Venus Express. I should note up-front gravity waves are NOT the same as gravitational waves

Artist impression: ESA

The ESA introduction:
Schematic illustration of the proposed behaviour of gravity waves in the vicinity of mountainous terrain on Venus.

Winds pushing their way slowly across the mountainous slopes on the surface generate gravity waves – an atmospheric phenomenon also often seen in mountainous parts of Earth’s surface. These waves form when air ripples over bumpy surfaces. The waves then propagate vertically upwards, growing larger and larger in amplitude until they break just below the cloud-top, like sea waves on a shoreline. As the waves break, they push back against the fast-moving high-altitude winds and slow them down.

Now for the whole story.

The Heart of the Crab

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This image is a composite of separate exposures acquired by the ACS/WFC instrument using several filters. Coloration results from assigning different hues (colors) to the grayscale image associated with an individual filter.The assigned colors represent not only changes in different filters, but also the same filters taken on different exposure dates to highlight features that change over time.

Credit: ESA / NASA Acknowledgment: J. Hester (ASU) and M. Weisskopf (NASA/GSFC)

From Hubblesite:
At the center of the Crab Nebula, located in the constellation Taurus, lies a celestial “beating heart” that is an example of extreme physics in space. The tiny object blasts out blistering pulses of radiation 30 times a second with unbelievable clock-like precision. Astronomers soon figured out that it was the crushed core of an exploded star, called a neutron star, which wildly spins like a blender on puree. The burned-out stellar core can do this without flying apart because it is 10 billion times stronger than steel. This incredible density means that the mass of 1.4 suns has been crushed into a solid ball of neutrons no bigger than the width of a large city. This Hubble image captures the region around the neutron star. It is unleashing copious amounts of energy that are pushing on the expanding cloud of debris from the supernova explosion — like an animal rattling its cage. This includes wave-like tsunamis of charged particles embedded in deadly magnetic fields.

On July 4, 1054, Chinese astronomers recorded the supernova that formed the Crab Nebula. The ultimate celestial firework, this “guest star” was visible during the daytime for 23 days, shining six times brighter than the planet Venus. The supernova was also recorded by Japanese, Arabic, and Native American stargazers. While searching for a comet that was predicted to return in 1758, French astronomer Charles Messier discovered a hazy nebula in the direction of the long-vanished supernova. He would later add it to his celestial catalog as “Messier 1.” Because M1 didn’t move across the sky like a comet, Messier simply ignored it other than just marking it as a “fake comet.” Nearly a century later the British astronomer William Parsons sketched the nebula. Its resemblance to a crustacean led to M1’s other name, the Crab Nebula. In 1928 Edwin Hubble first proposed associating the Crab Nebula to the Chinese “guest star” of 1054.

Parachute Testing

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I must confess, every time I see one of these parachute tests I quickly start wondering how that anchor point is constructed. I know, technically it’s not difficult, I just seem to have this need to know what the force at the base of the column is. Some day I will gather the data and do an estimate – and yes I say that every time. I forget quickly.

Check out what the parachute must do and be amazed at what the parachute must do.

From ESA:

This is a test version of the parachute that will slow the Schiaparelli entry, descent and landing module as they plummet through the martian atmosphere on 19 October.

When the module is about 11 km from the surface, descending at about 1700 km/h, the parachute will be deployed by a mortar. The parachute will slow the module to about 200 km/h by 1.2 km above the surface, at which stage it will be jettisoned.

The parachute is a ‘disc-gap-band’ type, as used for the ESA Huygens probe descent to Titan and for all NASA planetary entries so far.

The canopy, with a normal diameter of 12 m, is made from nylon fabric and the lines are made from Kevlar, a very strong synthetic material.

Tests of how the parachute will inflate at supersonic speeds were carried out with a smaller model in a supersonic wind tunnel in the NASA Glenn Research Center.

The full-scale qualification model, pictured here, was used to test the pyrotechnic mortar deployment and the strength of the parachute in the world’s largest wind tunnel, operated by the US Air Force at the National Full-Scale Aerodynamic Complex in the Ames Research Center, California.

The tower is needed to place the mortar – the horizontal tube at the top of the tower – at the centre of the wind tunnel for testing.

Schiaparelli was launched on 14 March with the Trace Gas Orbiter on a Proton rocket from the Baikonur Cosmodrome in Kazakstan.

Image: USAF Arnold Engineering Development Complex

Herschel’s Little Fox

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Herschel and ESA (via NASA):

New stars are the lifeblood of our galaxy, and there is enough material revealed by this Herschel infrared image to build stars for millions of years to come.

Situated 8,000 light-years away in the constellation Vulpecula — Latin for “little fox” — the region in the image is known as Vulpecula OB1. It is a “stellar association” in which a batch of truly giant “OB” stars is being born. O and B stars are the largest stars that can form.

The giant stars at the heart of Vulpecula OB1 are some of the biggest in the galaxy. Containing dozens of times the mass of the sun, they have short lives, astronomically speaking, because they burn their fuel so quickly. At an estimated age of 2 million years, they are already well through their lifespans. When their fuel runs out, they will collapse and explode as supernovas. The shock this will send through the surrounding cloud will trigger the birth of even more stars, and the cycle will begin again.

O stars are at least 16 times more massive than the sun, and could be well over 100 times as massive. They are anywhere from 30,000 to 1 million times brighter than the sun, but they only live up to a few million years before exploding. B-stars are between two and 16 times as massive as the sun. They can range from 25 to 30,000 times brighter than the sun.

OB associations are regions with collections of O and B stars. Since OB stars have such short lives, finding them in large numbers indicates the region must be a strong site of ongoing star formation, which will include many more smaller stars that will survive far longer.

The vast quantities of ultraviolet light and other radiation emitted by these stars is compressing the surrounding cloud, causing nearby regions of dust and gas to begin the collapse into more new stars. In time, this process will “eat” its way through the cloud, transforming some of the raw material into shining new stars.

The image was obtained as part of Herschel’s Hi-GAL key-project. This used the infrared space observatory’s instruments to image the entire galactic plane in five different infrared wavelengths.

These wavelengths reveal cold material, most of it between -220º C and -260º C. None of it can be seen in ordinary optical wavelengths, but this infrared view shows astronomers a surprising amount of structure in the cloud’s interior.

The surprise is that the Hi-GAL survey has revealed a spider’s web of filaments that stretches across the star-forming regions of our galaxy. Part of this vast network can be seen in this image as a filigree of red and orange threads.

In visual wavelengths, the OB association is linked to a star cluster catalogued as NGC 6823. It was discovered by William Herschel in 1785 and contains 50 to 100 stars. A nebula emitting visible light, catalogued as NGC 6820, is also part of this multi-faceted star-forming region.

Herschel is a European Space Agency mission, with science instruments provided by consortia of European institutes and with important participation by NASA. While the observatory stopped making science observations in April 2013, after running out of liquid coolant as expected, scientists continue to analyze its data. NASA’s Herschel Project Office is based at NASA’s Jet Propulsion Laboratory, Pasadena, California. JPL contributed mission-enabling technology for two of Herschel’s three science instruments. The NASA Herschel Science Center, part of the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, supports the U.S. astronomical community. Caltech manages JPL for NASA.

Image: ESA/Herschel/PACS, SPIRE/Hi-GAL Project

ESA May Take AIM

Ever wonder how ESA is going to top the Rosetta mission and the landing of Philae on the surface of comet 67P/Churyumov–Gerasimenko?

If approved the Asteroid Impact Mission would put a microlander called Mascot-2 would be deployed from the main AIM spacecraft to touch down on the approximately 170-m diameter ‘Didymoon’, in orbit around the larger 700-m diameter Didymos asteroid.

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