European Space Agency
Dark Matter Less Influential in Galaxies in Early Universe
Reinhard Genzel
Director, Max-Planck-Institut für extraterrestrische Physik
Garching bei München, Germany
March 15, 2017
VLT observations of distant galaxies suggest they were dominated by normal matter
We see normal matter as brightly shining stars, glowing gas and clouds of dust. But the more elusive dark matter does not emit, absorb or reflect light and can only be observed via its gravitational effects. The presence of dark matter can explain why the outer parts of nearby spiral galaxies rotate more quickly than would be expected if only the normal matter that we can see directly were present [1].
Now, an international team of astronomers led by Reinhard Genzel at the Max Planck Institute for Extraterrestrial Physics in Garching, Germany have used the KMOS and SINFONI instruments at ESO’s Very Large Telescope in Chile [2] to measure the rotation of six massive, star-forming galaxies in the distant Universe, at the peak of galaxy formation 10 billion years ago.
What they found was intriguing: unlike spiral galaxies in the modern Universe, the outer regions of these distant galaxies seem to be rotating more slowly than regions closer to the core — suggesting there is less dark matter present than expected [3].
Ancient Stardust Sheds Light on the First Stars
This research was presented in a paper entitled “Dust in the Reionization Era: ALMA Observations of a z =8.38 Gravitationally-Lensed Galaxy”
by Laporte et al., to appear in The Astrophysical Journal Letters.
An international team of astronomers, led by Nicolas Laporte of University College London, have used the Atacama Large Millimeter/submillimeter Array (ALMA) to observe A2744_YD4, the youngest and most remote galaxy ever seen by ALMA. They were surprised to find that this youthful galaxy contained an abundance of interstellar dust — dust formed by the deaths of an earlier generation of stars.
Follow-up observations using the X-shooter instrument on ESO’s Very Large Telescope confirmed the enormous distance to A2744_YD4. The galaxy appears to us as it was when the Universe was only 600 million years old, during the period when the first stars and galaxies were forming [1].
Ultracool Dwarf and the Seven Planets
Dr. Paola Rebusco
MIT – Experimental Study Group
ESON USA
eson-usa@eso.org
Astronomers using the TRAPPIST–South telescope at ESO’s La Silla Observatory, the Very Large Telescope (VLT) at Paranal and the NASA Spitzer Space Telescope, as well as other telescopes around the world [1], have now confirmed the existence of at least seven small planets orbiting the cool red dwarf star TRAPPIST-1 [2]. All the planets, labelled TRAPPIST-1b, c, d, e, f, g and h in order of increasing distance from their parent star, have sizes similar to Earth [3].
(ESO) ALMA Starts Observing the Sun
Roman Brajsa
Hvar Observatory, University of Zagreb
Croatia
Ivica Skokic
Astronomical Institute of the Czech Academy of Sciences
Ondrejov, Czech Republic
Astronomers have harnessed the Atacama Large Millimeter/submillimeter Array (ALMA)‘s capabilities to image the millimetre-wavelength light emitted by the Sun’s chromosphere — the region that lies just above the photosphere, which forms the visible surface of the Sun. The solar campaign team, an international group of astronomers with members from Europe, North America and East Asia [1], produced the images as a demonstration of ALMA’s ability to study solar activity at longer wavelengths of light than are typically available to solar observatories on Earth.
Astronomers have studied the Sun and probed its dynamic surface and energetic atmosphere in many ways through the centuries. But, to achieve a fuller understanding, astronomers need to study it across the entire electromagnetic spectrum, including the millimetre and submillimetre portion that ALMA can observe.
Hubble Finds Big Brother of Halley’s Comet – Ripped Apart By White Dwarf
February 9, 2017
European Space Agency News Release
Siyi Xu
European Southern Observatory
Garching bei München, Germany
Mathias Jäger
ESA/Hubble, Public Information Officer
Garching, Germany
The international team of astronomers observed the white dwarf WD 1425+540, about 170 light-years from Earth in the constellation Boötes (the Herdsman) [1]. While studying the white dwarf’s atmosphere using both the NASA/ESA Hubble Space Telescope and the W. M. Keck Observatory the team found evidence that an object rather like a massive comet was falling onto the star, getting tidally disrupted while doing so.
The team determined that the object had a chemical composition similar to the famous Halley’s Comet in our own Solar System, but it was 100,000 times more massive and had twice the proportion of water as its local counterpart. Spectral analysis showed that the destroyed object was rich in the elements essential for life, including carbon, oxygen, sulphur and even nitrogen [2].
NASA Television to Provide Coverage of European – Mission Comet Touchdown
NASA New Media Releaase
September 28, 2016
MEDIA ADVISORY M16-113
NASA Television and the agency’s website will air the conclusion of ESA’s (European Space Agency’s) Rosetta mission from 6:15 to 8 a.m. EDT Friday, Sept. 30, with NASA commentary, interviews and analysis of the successful mission. The Rosetta mission will end with the controlled decent of the spacecraft onto the surface of comet 67P/Churyumov-Gerasimenko at around 7:20 a.m.
From 8:15 to 10:15 a.m., NASA scientists and engineers involved in ESA’s Rosetta mission will be available for live broadcast interviews from the European Space Operations Center in Darmstadt, Germany.
Read the rest of this entry »
NASA Scientists Find ‘Impossible’ Cloud on Titan — Again
The puzzling appearance of an ice cloud seemingly out of thin air has prompted NASA scientists to suggest that a different process than previously thought — possibly similar to one seen over Earth’s poles — could be forming clouds on Saturn’s moon Titan.
Located in Titan’s stratosphere, the cloud is made of a compound of carbon and nitrogen known as dicyanoacetylene (C4N2), an ingredient in the chemical cocktail that colors the giant moon’s hazy, brownish-orange atmosphere.
NASA Team Probes Peculiar Age-Defying Star
For years, astronomers have puzzled over a massive star lodged deep in the Milky Way that shows conflicting signs of being extremely old and extremely young.
Researchers initially classified the star as elderly, perhaps a red supergiant. But a new study by a NASA-led team of researchers suggests that the object, labeled IRAS 19312+1950, might be something quite different — a protostar, a star still in the making.
NASA’s LISA Pathfinder Thrusters Operated Successfully
While some technologies were created to make spacecraft move billions of miles, the Disturbance Reduction System has the opposite goal: To keep a spacecraft as still as possible.
The thruster system, managed by NASA’s Jet Propulsion Laboratory, Pasadena, California, is part of the European Space Agency’s LISA Pathfinder spacecraft, which launched from Kourou, French Guiana on Dec. 3, 2015 GMT (Dec. 2 PST). LISA Pathfinder will test technologies that could one day allow detection of gravitational waves, whose effects are so miniscule that a spacecraft would need to remain extremely steady to detect them. Observing gravitational waves would be a huge step forward in our understanding of the evolution of the universe.
Now, LISA Pathfinder is on its way to Lagrange Point L1, about 930,000 miles (1.5 million kilometers) from Earth in the direction of the sun. L1 is a special point that a spacecraft can orbit while maintaining a nearly constant distance to Earth. This month, scientists and engineers have been switching on LISA Pathfinder’s instruments to test them in space. This has included the Disturbance Reduction System instrument computer and thrusters.
The system uses colloid micronewton thrusters, which operate by applying an electric charge to small droplets of liquid and accelerating them through an electric field, to precisely control the position of the spacecraft. Thrusters that work this way had never been successfully operated in space before LISA Pathfinder launched.
As of Jan. 10, all eight identical thrusters, developed by Busek Co., Natick, Massachusetts, with technical support from JPL, passed their functional tests. The thrusters achieved their maximum thrust of 30 micronewtons, equivalent to the weight of a mosquito. This level of precision is necessary to counteract small forces on the spacecraft such as the pressure of sunlight, with the result that the spacecraft and the instruments inside are in near-perfect free-fall. A mission to detect gravitational waves would need that level of stability.
“We reached a major milestone with this technology development,” said Phil Barela, Disturbance Reduction System project manager at JPL. “The DRS is helping point the way to a system that could be used to detect gravitational waves in the future.”
Gravitational waves are one of the last unverified predictions from the theory of General Relativity, which Albert Einstein published about a century ago. Einstein wrote that as massive bodies accelerate, such as black holes, they produce distortions in space-time. Scientists are interested in observing and characterizing these ripples in space-time so that they can learn more about the astrophysical systems that produce them, and about gravity itself. Proposed experiments to detect them from space, such as a future LISA mission, would need to measure how two freely-falling objects move ever so slightly, relative to each other, as a result of gravitational waves. In order to rule out any disturbances that could mask these waves, there must be a system to compensate for solar pressure and other factors. The Disturbance Reduction System on LISA Pathfinder will demonstrate this technology.
The Disturbance Reduction System could also lead to advanced thruster systems for other space applications. Space telescopes need to be very stable to detect distant planets in other solar systems, for example, and could use a similar system. A set of thrusters like the Disturbance Reduction System’s could also be used in small satellites to help synchronize flying patterns.
LISA Pathfinder will reach its final orbit on Jan. 22, and begin science operations on March 1. For the first phase of the mission’s science operations, a thruster technology system designed by the European Space Agency will be used. JPL’s Disturbance Reduction System will then take over in June or July, operating for 90 days.
LISA Pathfinder is managed by the European Space Agency. The spacecraft was built by Airbus Defence and Space, Ltd., United Kingdom. Airbus Defence and Space, GmbH, Germany, is the payload architect for the LISA Technology Package. The DRS is managed by JPL. The California Institute of Technology manages JPL for NASA.
The Climate Cube on the Champs-Elysees In Paris (Eurpean Space Agency)
Many locals and visitors to Paris are discovering a strange, large cube sitting on the Champs-Elysées.
Put in place by ESA and France’s CNES space agency, the Climate Cube is displaying the essential contribution of space and its applications on studying climate change, ahead of the COP21 climate change conference to be held in Paris from 30 November to 11 December.
With a huge screen on one of its 7 m sides, the Climate Cube focuses on how vital satellites are for understanding climate change, and how space is playing a major role in climate research and climate change mitigation.
While a series of videos on space and climate runs continuously on the screen, the other three sides offer an overview of European satellite missions measuring the ‘essential climate variables’ – 26 out of 50 are measurable only from space.
The Cube also features a high-resolution satellite image of Paris and surroundings, captured by ESA’s Sentinel-2A satellite.
The Climate Cube is standing on the Champs-Élysées, in front of the Grand Palais, 17—27 October. The nearest metro station is Place Clemenceau metro Champs-Elysées – Clemenceau.
About the European Space Agency
The European Space Agency (ESA) provides Europe’s gateway to space.
ESA is an intergovernmental organisation, created in 1975, with the mission to shape the development of Europe’s space capability and ensure that investment in space delivers benefits to the citizens of Europe and the world.
ESA has 21 Member States: Austria, Belgium, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg, the Netherlands, Norway, Poland, Portugal, Romania, Spain, Sweden, Switzerland and the United Kingdom, of whom 19 are Member States of the EU.
One other Member State of the EU, Hungary, has signed the Accession Agreement to the ESA Convention and, upon ratification, will soon become the 22nd ESA Member State.
ESA has established formal cooperation with seven other Member States of the EU.
Canada takes part in some ESA programmes under a Cooperation Agreement.
ESA is also working with the EU on implementing the Galileo and Copernicus programmes.
By coordinating the financial and intellectual resources of its members, ESA can undertake programmes and activities far beyond the scope of any single European country.
ESA develops the launchers, spacecraft and ground facilities needed to keep Europe at the forefront of global space activities.
Today, it develops and launches satellites for Earth observation, navigation, telecommunications and astronomy, sends probes to the far reaches of the Solar System and cooperates in the human exploration of space.
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