3D images show what lies beneath Mars poles

January 4, 2017

Washington, Jan 4: Scientists using data from a NASA probe have unveiled 3D subsurface images of Mars polar ice caps, showing previously obscured layering, larger volume of frozen carbon dioxide and bowl-shaped features that may be buried impact craters.mars

The information will help scientists better understand Martian climate changes and may allow them to determine the age of the polar caps without using climate models.

The 3D data volumes were assembled from observations by the Shallow Radar (SHARAD) onboard NASA's Mars Reconnaissance Orbiter (MRO) during more than 2000 orbit passes over each Martian pole.

"We have applied industry-developed techniques in a very novel fashion to a martian dataset, producing 3D volumes that are each over 600 times larger than any terrestrial or planetary dataset of this kind," said Nathaniel E Putzig, a senior scientist at the Planetary Science Institute in the US.

"It is gratifying to see so plainly in the SHARAD volumes structures that took years of effort to characterise with the single-orbit profiles," Putzig said.

Layering seen at the surface of the martian polar caps has been studied for decades. It has long been thought to represent a record of climate changes on that planet.

The interior structures of the caps remained a mystery until the arrival of radar sounders at Mars in the last decade.

An early version of the north polar 3D volume helped to assess the quantity of water ice transferred to the polar caps in the most recent retreat from a martian ice age.

First looks at the south polar 3D volume indicate that previously mapped deposits of carbon dioxide ice are somewhat larger than reported.

In both polar 3D volumes, known impact craters in and near the polar caps that are partially filled with ice have distinctive bowl-shaped signatures in the radar data, and similar signatures are found elsewhere within the polar ices but without any surface expression.

Whether the latter structures truly are impact craters remains to be determined.
Age estimates of planetary surfaces throughout the solar system rely on statistical data for impact craters on the Moon's surface calibrated to radiometrically dated samples returned during the Apollo programme.

This method has been used to estimate the surface ages of the martian polar caps, but estimates for the ages of the caps themselves have had to rely on numerical models of past climate changes.

If a sufficient number of the bowl-shaped features found in the radar volumes are shown to be impact craters, scientists will be able to assess the age of the polar caps using cratering statistics alone.

The extent to which age estimates from this new volumetric method agree or disagree with those from climate models will have important implications for the accuracy of these dating techniques.

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Agencies
February 5,2020

San Francisco, Feb 5: After a German artist, Simon Weckert, demonstrated how he "hacked" Google Maps with 99 smartphones and a wagon to create "virtual traffic jams" on the streets of Berlin, Google responded to the incident saying it "appreciates" creative use of maps.

Admitting that it has not quite cracked travelling by wagon, the tech giant also hinted that it might use cases like this to improve how its maps work.

"We appreciate seeing creative uses of Google Maps like this as it helps us make maps work better over time," 9to5Google quoted a Google spokesperson as saying.

In a YouTube video, Weckert showed that he put 99 smartphones with Google Maps onto a small wagon cart and then wheeled that cart around various streets in Berlin, including outside the Google office, Android Authority reported on Monday.

The smartphones "apparently fooled Google Maps" into thinking that there was a high concentration of users on those streets.

Because the second-hand phones were in a cart, Maps was further tricked into believing that the traffic was slow-moving.

As a result, the navigation app started showing virtual traffic jams by turning green streets to red in the online navigational tool, showcasing how digital technology can have a real impact on the real world.

"Traffic data in Google Maps is refreshed continuously thanks to information from a variety of sources, including aggregated anonymised data from people who have location services turned on and contributions from the Google Maps community," the Google spokesperson said.

"We've launched the ability to distinguish between cars and motorcycles in several countries including India, Indonesia and Egypt, though we haven't quite cracked travelling by wagon," the statement added. After a German artist, Simon Weckert, demonstrated how he "hacked" Google Maps with 99 smartphones and a wagon to create "virtual traffic jams" on the streets of Berlin, Google responded to the incident saying it "appreciates" creative use of maps.

Admitting that it has not quite cracked travelling by wagon, the tech giant also hinted that it might use cases like this to improve how its maps work.

"We appreciate seeing creative uses of Google Maps like this as it helps us make maps work better over time," 9to5Google quoted a Google spokesperson as saying.

In a YouTube video, Weckert showed that he put 99 smartphones with Google Maps onto a small wagon cart and then wheeled that cart around various streets in Berlin, including outside the Google office, Android Authority reported on Monday.

The smartphones "apparently fooled Google Maps" into thinking that there was a high concentration of users on those streets.

Because the second-hand phones were in a cart, Maps was further tricked into believing that the traffic was slow-moving.

As a result, the navigation app started showing virtual traffic jams by turning green streets to red in the online navigational tool, showcasing how digital technology can have a real impact on the real world.

"Traffic data in Google Maps is refreshed continuously thanks to information from a variety of sources, including aggregated anonymised data from people who have location services turned on and contributions from the Google Maps community," the Google spokesperson said.

"We've launched the ability to distinguish between cars and motorcycles in several countries including India, Indonesia and Egypt, though we haven't quite cracked travelling by wagon," the statement added.

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July 2,2020

Paris, Jul 2: Several interacting exoplanets have already been spotted by satellites. But a new breakthrough has been achieved with, for the first time, the detection directly from the ground of an extrasolar system of this type.

An international collaboration including CNRS researchers has discovered an unusual planetary system, dubbed WASP-148, using the French instrument SOPHIE at the Observatoire de Haute-Provence (CNRS/Aix-Marseille Universite).

The scientists analysed the star's motion and concluded that it hosted two planets, WASP-148b and WASP-148c. The observations showed that the two planets were strongly interacting, which was confirmed from other data.

Whereas the first planet, WASP-148b, orbits its star in nearly nine days, the second one, WASP-148c, takes four times longer. This ratio between the orbital periods implies that the WASP-148 system is close to resonance, meaning that there is enhanced gravitational interaction between the two planets. And it turns out that the astronomers did indeed detect variations in the orbital periods of the planets.

While a single planet, uninfluenced by a second one, would move with a constant period, WASP-148b and WASP-148c undergo acceleration and deceleration that provides evidence of their interaction.

The study will shortly be published in the journal Astronomy & Astrophysics.

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February 6,2020

Washington D.C., Feb 6: An international team of astronomers has found an unusual monster galaxy that existed about 12 billion years ago when the universe was only 1.8 billion years old.

The team of astronomers was led by scientists at the University of California, Riverside.

Dubbed XMM-2599, the galaxy formed stars at a high rate and then died. Why it suddenly stopped forming stars is unclear.

"Even before the universe was 2 billion years old, XMM-2599 had already formed a mass of more than 300 billion suns, making it an ultra massive galaxy," said Benjamin Forrest, a postdoctoral researcher in the UC Riverside Department of Physics and Astronomy and the study's lead author.

"More remarkably, we show that XMM-2599 formed most of its stars in a huge frenzy when the universe was less than 1 billion years old and then became inactive by the time the universe was only 1.8 billion years old," Forrest added.

The team used spectroscopic observations from the W. M. Keck Observatory's powerful Multi-Object Spectrograph for Infrared Exploration or MOSFIRE, to make detailed measurements of XMM-2599 and precisely quantify its distance.

The study results appear in the Astrophysical Journal.

"In this epoch, very few galaxies have stopped forming stars, and none are as massive as XMM-2599," said Gillian Wilson, a professor of physics and astronomy at UCR in whose lab Forrest works.

"The mere existence of ultramassive galaxies like XMM-2599 proves quite a challenge to numerical models. Even though such massive galaxies are incredibly rare at this epoch, the models do predict them."

"The predicted galaxies, however, are expected to be actively forming stars. What makes XMM-2599 so interesting, unusual, and surprising is that it is no longer forming stars, perhaps because it stopped getting fuel or its black hole began to turn on. Our results call for changes in how models turn off star formation in early galaxies," the professor stated.

The research team found XMM-2599 formed more than 1,000 solar masses a year in stars at its peak of activity -- an extremely high rate of star formation. In contrast, the Milky Way forms about one new star a year.

"XMM-2599 may be a descendant of a population of highly star-forming dusty galaxies in the very early universe that new infrared telescopes have recently discovered," said Danilo Marchesini, an associate professor of astronomy at Tufts University and a co-author on the study.

"We have caught XMM-2599 in its inactive phase," Wilson said, who led the W. M. Keck Observatory data acquisition
Co-author Michael Cooper, a professor of astronomy at UC Irvine, said this outcome is a strong possibility.

"Perhaps during the following 11.7 billion years of cosmic history, XMM-2599 will become the central member of one of the brightest and most massive clusters of galaxies in the local universe," he said.

"Alternatively, it could continue to exist in isolation. Or we could have a scenario that lies between these two outcomes," he stated.

The study was supported by grants from the National Science Foundation and NASA.

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