Tag Archives: radar

Radar Probes Titan’s Seas and Magic Islands

The Cassini Space Probe has measured the depth of a 40-kilometer-long stretch of Kraken Mare, the largest sea on Saturn’s moon Titan.

Shortly before capturing the first images showing Titan’s hydrocarbon seas with sunlight bouncing off of them, Cassini used radar to measure a strip of Kraken’s eastern side. Depths varied from 20 to 35 meters, but NASA cautions that these may be far from the deepest parts of the sea. 

The area studied during the August flyby is near the mouth of what on Earth would be considered a flooded river valley. Even though Titan’s rivers and seas are filled with hydrocarbons, probably methane and ethane rather than water, it is thought the processes of erosion and flooding are similar.

The study was part of a 200 kilometer sweep across the breadth of Kraken, but for the majority of this the results came back blank. NASA concluded that, “For the areas in which Cassini did not observe a radar echo from the seafloor, Kraken Mare might be too deep for the radar beam to penetrate.” An alternative possibility is that the still unknown make up of Titan’s seas varies, and the blank stretches represent more absorbent liquids.

The land around parts of the Kraken sea is quite steep, and if this continues beneath the surface, some sections might be deep enough to host the mythical beasts after which it is named.

At the same time, two bright features were seen in Kraken Mare that had not been visible on previous flybys. These may be related to the mysterious feature dubbed “magic island” that was spotted with a radar in Ligeia Mare last July before disappearing again a few days later. 

This time, however, both the Cassini radar and Visible and Infrared Mapping Spectrometer (VIMS) were focused on the right location, bolstering the opportunity to identify what causes these bright spots. Patches of waves or some form of debris are currently the favored explanations, with some alternatives such as fog or submarine icebergs having been ruled out.

The findings were presented to a workshop at the Planetary Sciences Division of the American Astronomical Society.

In January, NASA plans to do another radar sweep of Punga Mare, the smallest of the three bodies large enough to be designated seas. The same pass will provide an opportunity for researchers to study Ligeia for further clues as to the nature of these intermittent bright spots. This will be the last attempt to study Titan’s seas and sea floors before Cassini makes its final dive into Saturn to collect as much data as it can on the atmosphere of our solar system’s second largest planet before being crushed to oblivion.

H/T Space.com

Read more: http://www.iflscience.com/space/radar-probes-titans-seas-and-magic-islands

A Solar Storm Reportedly Made Airplanes Disappear From Radars

The Swedish civil aviation authorityclaims that a solar storm knocked out the air traffic control system in the country on Wednesday afternoon, and itwasforced to close its airspace for over an hour.

According to the aviation officials, the solar storm created enough disturbance in the Earths magnetic field to stop the radar system working properly.

Per Froberg, the spokesperson for Luftfartsverket (the Swedish Civil Aviation Administration), told the Associated Press that flights disappeared from radarscreens across Sweden. The radar blackout lasted for about an hour, but there is yet no explanation on why it was so severe.

“We’re working on sorting out the delays. We can’t examine the cause right now. We have our hands full,” MrFroberg added.

Neighboring countries such as Denmark and Finland didnt report any problems in their ground instrumentation. “There haven’t been any disturbances. Only a few delays in Copenhagen because of the problems in Stockholm,” Mette Just of Naviair, Denmark’s air navigation service, told the Associated Press.

And Juha-Pekka Luntama head of the European Space Agency’s Space Weather Coordination Centre told IFLScience it was too early to blame a solar storm for the blackout.

I think the event in Sweden yesterday was very interesting and we should wait for the technical analysis from the Swedish authorities before making any conclusions,he said.In my view the solar flare yesterday was not very strong and thus impacts in the air traffic control radar system in Sweden were unexpected.

He continued:”Theoretically this kind of disturbance is possible, but these events are very rare and they would require a substantial radio burst from the Sun. Unexpected impacts may, of course, be possible when many inputs combine in the worst possible way. However, I would expect that other technical reasons will be identified as the main course for the radar problem. [Although] it is still possible that the solar flare was somehow one of the contributing factors.

Solar storms happen when material from the Sun interacts strongly with the magnetic field of the Earth. The strongest interactions are due to shock waves in the solar wind (a stream of electrically charged particles constantly being emitted by the Sun), which are produced when eruptions from the solar surface are suddenly flung into space by freak magnetic events.

Solar storms can be very dangerous. One of the most intense solar storms in recent years was the Halloween Solar Storm of 2003, which caused an hour-long blackout in Sweden. The strongest solar storm on record, the Carrington event, happened in 1859. It was responsible for aurorae from the poles to the tropics as well as setting telegraph stations on fire across Europe and the United States. If it had happened today, it could produce trillions of dollars of damages inthe U.S. alone.

Read more: http://www.iflscience.com/airplanes-disappear-swedish-radars-due-solar-storm