SPIDER: 'Spacecraft' seeks traces of the early universe over Antartica

Constructed primarily in Princeton's Jadwin Hall, SPIDER is a stratospheric spacecraft that in December will begin a 20-day orbit in Earth's stratosphere at an altitude of roughly 110,000 feet.

During that period, SPIDER's six large cameras will look for the pattern, or polarization, of gravitational waves produced by the fluctuation of energy and density that resulted from the Big Bang.

These waves, explained William Jones a Princeton University assistant professor of physics, are a "statistically unique fingerprint" that can be traced back to the beginning of the universe.

Many astronomical instruments measure various characteristics of this fingerprint, SPIDER is designed to characterize the "shape" of it, said Jones, who is the project's principal investigator.

"The ultimate goal of SPIDER is to see to what extent we can identify a very characteristic feature in that polarization that's expected to come from the earliest stages of the evolutionary growth of our universe," Jones said.

"There's a very particular pattern than can be generated only by something like a gravitational wave propagating through the surface of the cosmic microwave background [which is the glow of the heat left over from the Big Bang]," Jones said.

"That is a very particular pattern commonly referred to as a 'pinwheel' pattern on the sky. It's that particular pinwheel pattern that we're really after."

SPIDER, which used to be an acronym, but now is the project's formal name, is a multi-institutional project funded largely by a grant from NASA, as well as the David and Lucille Packard Foundation.

In addition to Princeton, the primary institutions involved are the University of Toronto; Case Western Reserve University; the California Institute of Technology and the Jet Propulsion Laboratory, a NASA-funded research center managed by Caltech; and the University of British Columbia.

The project was proposed in 2006 while Jones, who joined Princeton's faculty in 2008, was a scientist at the Jet Propulsion Laboratory.

ESA CheOps: European satellite's mission to study exoplanets

Artist's impression of Cheops. Credit: University of Bern

The European Space Agency (ESA) has announced plans for a new mission to study exoplanets.

ESA hopes to launch the satellite in 2017. It comes as it was announced this week that a planet with a similar mass to Earth was detected in our nearest star system, Alpha Centauri.

The mission, called Cheops - CHaracterising ExOPlanets Satellite - will target nearby bright stars which are already known to have planets.

It's the first of a series of smaller missions developed as part of the space agency's Science Programme.

Cheops will monitor the brightness of our nearest stars to look for signs of transits, where planets cross in front of the star.

In turn, this will allow an accurate measurement of the radius of a transitting planet. Scientists then hope to calculate the density of these planets where the mass is already known. This will then help to provide information about the internal structure.

According to Professor Alvaro Giménez-Cañete, ESA Director of Science and Robotic Exploration "by concentrating on specific known exoplanet host stars, Cheops will enable scientists to conduct comparative studies of planets down to the mass of Earth with a precision that simply cannot be achieved from the ground."

The idea is to help scientists understand the formation of planets, up to the size of the planet Neptune. The mission also aims to identify planets with significant atmospheres.

Information from Cheops will then be used to provide targets for further detailed studies of exoplanet atmospheres by the future telescopes such as the James Webb Space Telescope, which is targeted to launch in 2018, and the European Extremely Large Telescope, which should be ready for use by 2022.

HiRISE: Concentric Structures in Meridiani Planum

This image shows a number of unusual, quasi-circular structures from 300 to 600 meters in diameter that apparently formed within bright flows in Meridiani Planum.

The strange structures were observed earlier in MOC image E12-01295.

They are located near the equator, about 300 kilometers West of the MER rover Opportunity.

New details can be seen in the HiRISE image that yield clues to the origin of these mysterious features.

The dark rings seen within the concentric structures appear rougher than their surroundings.

The bright material in which they formed is densely fractured, suggesting that it is quite brittle.

Several small impact craters found within the bright unit produced sprays of dark ejecta, suggesting that the bright surface layer may be only a few meters thick.

A compositional and morphological boundary separates the contorted central region of the unit from the smooth margins.

A full interpretation awaits detailed analysis, but these observations suggest that the lobate bright unit may have been produced by an ancient flow of water-saturated fluvial sediments.

The circular structures within the flow could have formed by desiccation, as the sediments dried out and contracted, similar to mud cracks but on a much larger scale. Or they may have formed by a process of diapirism, if a solid crust formed on the surface of the drying sediments that was denser than the water-saturated slurry below.

On Earth, slurries of sand and water that are pressurised by the weight of the overburden can rise to the surface to form "injectites," eruptions of sand and water that can reach heights of hundreds of meters.

Whether they were formed by desiccation or injection, these unusual features record a unique moment in the distant past of Mars.

Growth of density perturbations in both gas and dark matter components

All this is is “This simulation follows the growth of density perturbations in both gas and dark matter components in a volume 1 billion light years on a side beginning shortly after the Big Bang and evolved to half the present age of the universe. It calculates the gravitational clumping of intergalactic gas and dark matter modeled using a computational grid of 64 billion cells and 64 billion dark matter particles. The simulation uses a computational grid of 4096^3 cells and took over 4,000,000 CPU hours to complete.”