esa Archives

October 1, 2012December 23, 2015 by Nancy Atkinson

Surprise! Hot Venus has a Cold Upper Atmosphere

Venus’ terminator – the transitional region between day and night — may fuel an unusually cold region in the atmosphere. Credit: ESA/MPS, Katlenburg-Lindau, Germany

The hottest planet in the Solar System has a surprisingly cold region high in the planet’s atmosphere, according to new findings by the Venus Express spacecraft. While surface temperatures on this hot and hostile planet tops out at 735 Kelvin, or 462 degrees Celsius, ESA scientists say that a layer in the atmosphere about 125 km up has temperatures of around –175 degrees C, and may be cold enough for carbon dioxide to freeze out as ice or snow.

This means this curious cold layer is much colder than any part of Earth’s atmosphere even though Venus is known for its dense, blistering atmosphere and is much closer to the Sun. Additionally, the cold layer appears to be affected by the transitioning between day and night on Venus.

Scientists made the discovery by watching as light from the Sun filtered through the atmosphere to reveal the concentration of carbon dioxide gas molecules at various altitudes along the terminator – the dividing line between the day and night sides of the planet.

Then they combined data about the carbon dioxide concentration with data on atmospheric pressure at each height. The scientists could then calculate the corresponding temperatures.

“Since the temperature at some heights dips below the freezing temperature of carbon dioxide, we suspect that carbon dioxide ice might form there,” said Arnaud Mahieux of the Belgian Institute for Space Aeronomy and lead author of the paper reporting the results in the Journal of Geophysical Research.

The temperature profile along the terminator for altitudes of 70–160 km above the surface of Venus. Credit: ESA/AOES–A.V. Bernus

Source: ESA

Clouds of small carbon dioxide ice or snow particles should be very reflective, perhaps leading to brighter than normal sunlight layers in the atmosphere.

“However, although Venus Express indeed occasionally observes very bright regions in the Venusian atmosphere that could be explained by ice, they could also be caused by other atmospheric disturbances, so we need to be cautious,” said Mahieux.

The study also found that the cold layer at the terminator is sandwiched between two comparatively warmer layers.

“The temperature profiles on the hot dayside and cool night side at altitudes above 120 km are extremely different, so at the terminator we are in a regime of transition with effects coming from both sides.

“The night side may be playing a greater role at one given altitude and the dayside might be playing a larger role at other altitudes.”

Similar temperature profiles along the terminator have been derived from other Venus Express datasets, including measurements taken during the transit of Venus earlier this year.

Models are able to predict the observed profiles, but further confirmation will be provided by examining the role played by other atmospheric species, such as carbon monoxide, nitrogen and oxygen, which are more dominant than carbon dioxide at high altitudes.

“The finding is very new and we still need to think about and understand what the implications will be,” says Håkan Svedhem, ESA’s Venus Express project scientist. “But it is special, as we do not see a similar temperature profile along the terminator in the atmospheres of Earth or Mars, which have different chemical compositions and temperature conditions.”

July 28, 2012December 23, 2015 by Ken Kremer

T Minus 9 Days – Mars Orbiters Now in Place to Relay Critical Curiosity Landing Signals

Image Caption: NASA’s Mars Odyssey will relay near real time signals of this artist’s concept depicting the moment that NASA’s Curiosity rover touches down onto the Martian surface. NASA’s Mars Reconnaissance Orbiter (MRO) and ESA’s Mars Express (MEX) orbiter will also record signals from Curiosity for later playback, not in real time. Credit: NASA

It’s now just T minus 9 Days to the most difficult and complex Planetary science mission NASA has ever attempted ! The potential payoff is huge – Curiosity will search for signs of Martian life

The key NASA orbiter at Mars required to transmit radio signals of a near real-time confirmation of the August 5/6 Sunday night landing of NASA’s car sized Curiosity Mars Science Lab (MSL) rover is now successfully in place, and just in the nick of time, following a successful thruster firing on July 24.

Odyssey will transmit the key signals from Curiosity as she plunges into the Martian atmosphere at over 13,000 MPH (21,000 KPH) to begin the harrowing “7 Minutes of Terror” known as “Entry, Descent and Landing” or EDL – all of which is preprogrammed !

Engines aboard NASA’s long lived Mars Odyssey spacecraft fired for about 6 seconds to adjust the orbiters location about 6 minutes ahead in its orbit. This will allow Odyssey to provide a prompt confirmation of Curiosity’s landing inside Gale crater at about 1:31 a.m. EDT (531 GMT) early on Aug. 6 (10:31 p.m. PDT on Aug. 5) – as NASA had originally planned.

Without the orbital nudge, Odyssey would have arrived over the landing site about 2 minutes after Curiosity landed and the signals from Curiosity would have been delayed.

A monkey wrench was recently thrown into NASA relay signal plans when Odyssey unexpectedly went into safe mode on July 11 and engineers weren’t certain how long recovery operations would take.

“Information we are receiving indicates the maneuver has completed as planned,” said Mars Odyssey Project Manager Gaylon McSmith of NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “Odyssey has been working at Mars longer than any other spacecraft, so it is appropriate that it has a special role in supporting the newest arrival.”

Odyssey has been in orbit at Mars since 2001 conducting orbital science investigations.

Read my review article on Odyssey’s science discoveries – here

Odyssey serves as the primary communications relay for NASA’s other recent surface explorers – Opportunity, Spirit and Phoenix. Opportunity recently passed 3000 Sols of continuous operations.

Two other Mars orbiters, NASA’s Mars Reconnaissance Orbiter and the European Space Agency’s Mars Express, also will be in position to receive radio transmissions from the Mars Science Laboratory during its descent. However, they will be recording information for later playback, not relaying it immediately, as only Odyssey can.

“We began optimising our orbit several months ago, so that Mars Express will have an orbit that is properly “phased” and provides good visibility of MSL’s planned trajectory,” says Michel Denis, Mars Express Spacecraft Operations Manager.

Mars Express has been orbiting the planet since December 2003.

Image Caption: Mars Express supports Curiosity MSL. Credit: ESA

“NASA supported the arrival of Mars Express at Mars in 2003, and, in the past few years, we have relayed data from the rovers Spirit and Opportunity,” says ESA’s Manfred Warhaut, Head of Mission Operations.

“Mars Express also tracked the descent of NASA’s Phoenix lander in 2008 and we routinely share our deep space networks.

“Technical and scientific cooperation at Mars between ESA and NASA is a long-standing and mutually beneficial activity that helps us both to reduce risk and increase the return of scientific results.”

Watch NASA TV online for live coverage of Curiosity landing: mars.jpl.nasa.gov or www.nasa.gov

Ken Kremer

July 27, 2012December 23, 2015 by Jason Major

Europe’s Plans to Visit the Moon in 2018

The European Space Agency is aiming for the Moon with their Lunar Lander mission, anticipated to arrive on the lunar surface in 2018. Although ESA successfully put a lander on Titan with the Huygens probe in 2005, this will be the first European spacecraft to visit the surface of Earth’s Moon.

Although Lunar Lander will be an unmanned robotic explorer, the mission will be a forerunner to future human exploration of the Moon as well as Mars. Lunar Lander will use advanced technologies for autonomous landing and will be able to determine the best location for touchdown on its own, utilizing lasers to avoid obstacles on the Moon’s surface.

With no GPS on the Moon, Lunar Lander will navigate by digitally imaging the surface on the fly. Landing will be accomplished via thrusters, which were successfully tested earlier this year at a test chamber in Germany.

Lunar Lander’s destination will be the Moon’s south pole, where no exploration missions have ever landed. Once on the lunar surface, the Lander will investigate Moon dust using a robotic arm and a suite of onboard diagnostic instruments, sending data and images back to scientists on Earth for further study.

Watch a video of the Lunar Lander mission below, from launch to landing.

Read more about Lunar Lander on the ESA site here.

Images and video: ESA

July 19, 2012December 23, 2015 by Jason Major

Aurora Over Antarctica: a “Teardrop From Heaven”

“We managed to snap a few photos before Heaven realised its mistake and closed its doors.”
– Dr. Alexander Kumar

This stunning photo of the Aurora Australis, set against a backdrop of the Milky Way, was captured from one of the most remote research locations on the planet: the French-Italian Concordia Base, located located at 3,200 meters (nearly 10,500 feet) altitude on the Antarctic plateau, 1,670 km (1,037 miles) from the geographic south pole.

The photo was taken on July 18 by resident doctor and scientist Dr. Alexander Kumar and his colleague Erick Bondoux.

Sparked by a coronal mass ejection emitted from active region 11520 on July 12, Earth’s aurorae leapt into high gear both in the northern and southern hemispheres three days later during the resulting geomagnetic storm — giving some wonderful views to skywatchers in locations like Alaska, Scotland, New Zealand… and even the South Pole.

“A raw display of one of nature’s most incredible sights dazzled our crew,” Dr. Kumar wrote on his blog, Chronicles from Concordia. “The wind died down and life became still. To me, it was if Heaven had opened its windows and a teardrop had fallen from high above our station, breaking the dark lonely polar night.

“We managed to snap a few photos before Heaven realised its mistake and closed its doors.”

With winter temperatures as low as -70ºC (-100ºF), no sunlight and no transportation in or out from May to August, Concordia Base is incredibly isolated — so much so that it’s used for research for missions to Mars, where future explorers will face many of the same challenges and extreme conditions that are found at the Base.

But even though they may be isolated, Dr. Kumar and his colleagues are in an excellent location to witness amazing views of the sky, the likes of which are hard to find anywhere else on Earth. Many thanks to them for braving the bitter cold and otherworldly environment to share images like this with us!

Pulsar Sets New Speed Record

A pulsar may have been spotted racing through space at over 6 million miles per hour (9.65 million km/h), setting a new speed record for these curious cosmic objects. If observations are what they appear to be, astronomers will have to recalculate the incredible forces created by supernova explosions.

Seen in observations made with 3 different telescopes — NASA’s Chandra X-ray Observatory, ESA’s XMM-Newton, and the Parkes radio telescope in Australia — the x-ray-emitting object IGR J11014-6103 appears to be racing away from the remnants of a supernova in the constellation Carina, 30,000 light-years from Earth.

The comet-shaped object is thought to be a pulsar, the rapidly-spinning, superdense remains of a star. The facts that it’s dim in optical and infrared wavelengths and hasn’t changed in x-ray brightness between XMM-Newton observations in 2003 and Chandra measurements in 2011 support the claim.

IGR J11014’s comet-like shape may be the result of its breakneck speed through space as its pulsar wind nebula gets blown back by the high-energy bow shock created at the forefront of its passage.

Pulsar wind nebulae are the results of charged particles streaming out from the pulsar itself. The particles, traveling at nearly light-speed, are rapidly decelerated by the interstellar medium and create a visible shock wave. In the case of IGR J11014, the pulsar wind is formed into a “tail” by its bow shock — effectively a sonic boom in front of it.

Further observations will be needed to confirm that IGR J11014 is indeed a pulsar, especially considering that actual pulsations have not yet been detected. If it is a pulsar, and is really traveling at the record-breaking speeds it appears to be — between 5.4 and 6.5 million miles per hour, more than 12 times faster than the Sun travels around the center of the galaxy — a new model of supernova explosions may be required.

Read more on the Chandra news release here.

Image: X-ray: NASA/CXC/UC Berkeley/J.Tomsick et al & ESA/XMM-Newton, Optical: DSS; IR: 2MASS/UMass/IPAC-Caltech/NASA/NSF. Video: NASA/CXC/A. Hobart.

June 21, 2012December 23, 2015 by Jenny Winder

Euclid and the Geometry of the Dark Universe

Artist’s impression of Euclid Credit: ESA/C. Carreau

Euclid, an exciting new mission to map the geometry, distribution and evolution of dark energy and dark matter has just been formally adopted by ESA as part of their Cosmic Vision 2015-2025 progamme. Named after Euclid of Alexandria, the “Father of Geometry”, it will accurately measure the accelerated expansion of the Universe, bringing together one of the largest collaborations of astronomers, engineers and scientists in an attempt to answer one of the most important questions in cosmology: why is the expansion of the Universe accelerating, instead of slowing down due to the gravitational attraction of all the matter it contains?

In 2007 the Hubble Space Telescope produced a 3D map of dark matter that covered just over 2 square degrees of sky, while in March this year the Baryon Oscillation Spectroscopic Survey (BOSS) measured the precise distance to just over a quarter of a million galaxies. Working in the visible and near-infrared wavelengths, Euclid will precisely measure around two billion galaxies and galaxy clusters in 3 dimensions in a wide extragalactic survey covering 15,000 square degrees (over a third of the sky) plus a deep survey out to redshifts of ~2, covering an area of 40 square degrees, the 3-D galaxy maps produced will trace dark energy’s influence over 10 billion years of cosmic history, covering the period when dark energy accelerated the expansion of the Universe.

The mission was selected last October but now that it has been formally adopted by ESA, invitations to tender will be released, with Astrium and Thales Alenia Space, Europe’s two main space companies expected to bid. Hoping to launch in 2020, Euclid will involve contributions from 11 European space agencies as well as NASA while nearly 1,000 scientists from 100 institutes form the Euclid Consortium building the instruments and participating in the scientific harvest of the mission. It is expected to cost around 800m euros ($1,000m £640m) to build, equip, launch and operate over its nominal 6 year mission lifetime, where it will orbit the second Sun-Earth Lagrange point (L2 in the image below) It will have a mass of around 2100 kg, and measure about 4.5 metres tall by 3.1 metres. It will carry a 1.2 m Korsch telescope, a near infrared camera/spectrometer and one of the largest optical digital cameras ever flown in space.

Dark matter represents 20% of the universe and dark energy 76%. Euclid will use two techniques to map the dark matter and measure dark energy. Weak gravitational lensing measures the distortions of light from distant galaxies due to the mass of dark matter, this requires extremely high image quality to suppress or calibrate-out image distortions in order to measure the true distortions by gravity. Euclid’s camera will produce images 100 times larger than those produced by Hubble, minimizing the need to stitch images together. Baryonic acoustic oscillations, wiggle patterns, imprinted in the clustering of galaxies, will provide a standard ruler to measure dark energy and the expansion in the Universe. This involves the determination of the redshifts of galaxies to better than 0.1%. It is also hoped that later in the mission, supernovas may be used as markers to measure the expansion rate of the Universe.

Find out more about Euclid and other Cosmic Vision missions at ESA Science

Lead image caption: Artist’s-impression-of-Euclid-Credit-ESA-C.-Carreau

Second image caption: Sun Earth Lagrange Points Credit: Xander89 via Wikimedia Commons

June 20, 2012December 23, 2015 by John Williams

Early Black Holes were Grazers Rather than Glutonous Eaters

Faint quasars powered by black holes. Image credit NASA/ESA/Yale

Black holes powering distant quasars in the early Universe grazed on patches of gas or passing galaxies rather than glutting themselves in dramatic collisions according to new observations from NASA’s Spitzer and Hubble space telescopes.

A black hole doesn’t need much gas to satisfy its hunger and turn into a quasar, says study leader Kevin Schawinski of Yale “There’s more than enough gas within a few light-years from the center of our Milky Way to turn it into a quasar,” Schawinski explained. “It just doesn’t happen. But it could happen if one of those small clouds of gas ran into the black hole. Random motions and stirrings inside the galaxy would channel gas into the black hole. Ten billion years ago, those random motions were more common and there was more gas to go around. Small galaxies also were more abundant and were swallowed up by larger galaxies.”

Quasars are distant and brilliant galactic powerhouses. These far-off objects are powered by black holes that glut themselves on captured material; this in turn heats the matter to millions of degrees making it super luminous. The brightest quasars reside in galaxies pushed and pulled by mergers and interactions with other galaxies leaving a lot of material to be gobbled up by the super-massive black holes residing in the galactic cores.

Schawinski and his team studied 30 quasars with NASA’s orbiting telescopes Hubble and Spitzer. These quasars, glowing extremely bright in the infrared images (a telltale sign that resident black holes are actively scooping up gas and dust into their gravitational whirlpool) formed during a time of peak black-hole growth between eight and twelve billion years ago. They found 26 of the host galaxies, all about the size of our own Milky Way Galaxy, showed no signs of collisions, such as smashed arms, distorted shapes or long tidal tails. Only one galaxy in the study showed evidence of an interaction. This finding supports evidence that the creation of the most massive black holes in the early Universe was fueled not by dramatic bursts of major mergers but by smaller, long-term events.

“Quasars that are products of galaxy collisions are very bright,” Schawinski said. “The objects we looked at in this study are the more typical quasars. They’re a lot less luminous. The brilliant quasars born of galaxy mergers get all the attention because they are so bright and their host galaxies are so messed up. But the typical bread-and-butter quasars are actually where most of the black-hole growth is happening. They are the norm, and they don’t need the drama of a collision to shine.

“I think it’s a combination of processes, such as random stirring of gas, supernovae blasts, swallowing of small bodies, and streams of gas and stars feeding material into the nucleus,” Schawinski said.

Unfortunately, the process powering the quasars and their black holes lies below the detection of Hubble making them prime targets for the upcoming James Webb Space Telescope, a large infrared orbiting observatory scheduled for launch in 2018.

You can learn more about the images here.

Image caption: These galaxies have so much dust enshrouding them that the brilliant light from their quasars cannot be seen in these images from the NASA/ESA Hubble Space Telescope.

June 18, 2012December 23, 2015 by Jason Major

Milky Way to Concordia Base… Come In, Concordia Base…

This stunning photo of the Milky Way was captured from what may be the coldest and most isolated research facility on Earth: the French-Italian Concordia Base station, located at 3,200 meters (nearly 10,500 feet) altitude on the Antarctic plateau, 1,670 km (1,037 miles) from the geographic south pole.

Taken by Dr. Alexander Kumar, a doctor, researcher and photographer who’s been living at the Base since January, the image shows the full beauty of the sky above the southern continent — a sky that doesn’t see the Sun from May to August.

During the winter months no transportation can be made to or from Concordia Base — no deliveries or evacuations, not for any reason. The team there is truly alone, very much like future space explorers will one day be. This isolation is one reason that Concordia is used by ESA for research for missions to Mars.

Of course, taking photos outside is no easy task. Temperatures outside the Base in winter can drop down to -70ºC (-100ºF)!

Still, despite the isolation, darkness and cold, Dr. Kumar finds inspiration in his surroundings.

“The dark may cause fear, but if you take the time to adapt and look within it, you never know what you may find – at the bottom of the ocean, in the night sky, or under your bed in the middle of the night,” writes Kumar on the Concordia blog. “If you don’t overcome your fear of the ‘unknown’ and ‘monsters’, you will never see marvellous secrets hidden in the dark.

“I hope this photo inspires you too for the days, weeks and months ahead. In terms of the space exploration we are only beginning. We have to continue pushing out into the great beyond.”

Image credits: ESA/IPEV/PNRA – A. Kumar

June 11, 2012December 23, 2015 by Jason Major

Lightning From Space!

Photo of Earthly lightning seen from orbit by ESA astronaut Andre Kuipers

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Here’s an amazing shot of a flash of lightning within storm clouds over west Africa, captured from orbit by ESA astronaut André Kuipers aboard the ISS.

Lightning is a common sight from Space Station, creating a constant light show for the astronaut and cosmonaut crew members. On average, lightning strikes the ground somewhere on Earth 100 times each second, and there are 5 to 10 times as many cloud-to-cloud flashes as there are ground strikes. That adds up to about 40 to 80 million flashes of lightning every day around the world! Considering that the ISS orbits Earth 16 times a day — and from quite a high viewpoint — it stands to reason that lightning is spotted quite often.

So although it may not be rare, lightning still makes for dramatic photos — especially to those of us here on the ground!

For more information on André and his ongoing long-duration PromISSe mission, visit the ESA site here.

Image credit: ESA/NASA

June 5, 2012December 23, 2015 by Jason Major

Tomorrow’s Transit Will be the First Photographed From Space

Venus photographed from the ISS (ESA/NASA)

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ESA astronaut Andre Kuipers captured this stunning image of Earth’s limb with Venus shining brightly above on the morning of June 4, 2012. While it’s a fantastic shot in its own right, it’s just a warm-up for tomorrow’s big transit event, which will be watched by millions of people all over the world — as well as a select few aboard the ISS!

While many people will be taking advantage of this last opportunity to see Venus pass across the face of the Sun — a relatively rare event that’s only happened six times since the invention of the telescope, and won’t occur again until 2117 — the crew of the International Space Station is preparing to become the first astronaut to photograph it from space!

Transit of Venus by NASA's TRACE spacecraft Image credit: NASA/LMSAL — Transit of Venus in 2004 by NASA's TRACE spacecraft. Image credit: NASA/LMSAL

Expedition 31 flight engineer Don Pettit knew he’d be up in orbit when this transit takes place, and he went prepared.

“I’ve been planning this for a while,” says Pettit. “I knew the Transit of Venus would occur during my rotation, so I brought a solar filter with me when my expedition left for the ISS in December 2011.”

(See more of Don Pettit’s in-orbit photography: Timelapse of a Moonrise Seen From The ISS)

Even though the 2004 transit happened while the ISS was manned, the crew then didn’t have filters through with to safely view it.

Pettit will be shooting the transit through the windows of the cupola. He’ll even be removing a scratch-resistant layer first, in order to get the sharpest, clearest images possible — only the third time that’s ever been done.

Don’s images should be — no pun intended — brilliant.

“I’ll be using a high-end Nikon D2Xs camera and an 800mm lens with a full-aperture white light solar filter,” he says.

And if you want to follow along with the transit as it’s seen from down here on Earth, be sure to tune in to Universe Today’s live broadcast on Tuesday, June 5 at 5 p.m. EDT where Fraser Cain will be hosting a marathon event along with guests Pamela Gay, Phil Plait (a.k.a. the Bad Astronomer) and more as live views are shared from around the world.

Unless you plan on being around in 2117, this will be your last chance to witness a transit of Venus!

Read more about Don Pettit’s photo op on NASA Science News here.