Spectrographic MARSIS data from radar soundings of the Martian ionosphere midway between the equator and north pole at three different times. The horizontal axis is the MARSIS radio wave pulse frequency. The vertical axis is the estimated altitude above the planet’s surface. Increasing intensity is indicated by color-coding from blue to red, as shown by the scale. The normal ionospheric reflection can be seen extending up to about 2.8 megahertz on all three spectrograms, corresponding to an electron density of about 100,000 electrons per cubic centimeter. The top spectrogram shows conditions about eight minutes before the comet’s closest approach. The middle spectrogram shows conditions about seven hours later, when a temporary layer of enhanced electron density had formed within the ionosphere. It extends to very high frequencies, from about 2.8 to 3.8 megahertz, and corresponds to an electron density of about 200,000 electrons per cubic centimeter. This layer is at an altitude below the normal peak in the ionosphere. By comparison with the ground reflection, which can be seen at frequencies above 4 megahertz, the layer of enhanced ionization is estimated to be at an altitude of 50 to 60 miles. Credit: ASI/NASA/ESA/JPL/Univ. of Rome/Univ. of Iowa
Here’s a little bit of everything (almost) going on in Iowa science, from the interplanetary to the tiny and from the latest in robotics to the history of Iowa’s role in the atom bomb.
University of Iowa researchers last week released results from a probe that tracked the impact of a comet flyby on Mars’ atmosphere. The impact was something like a massive meteor shower.
On Earth, Iowa State University plant scientists plan to staff a high-tech growing facility with a robot. (Don’t worry, postdocs and grad students; I’m sure they’ll need some human help, too.)
Ames Laboratory researchers, meanwhile, have taken a mathematical look at the uncomfortable situation that occurs when tiny particles meet in a nanoparticle’s narrow pores. It’s a bit like people trying to squeeze past each other in a tight hallway.
And finally, for hardcore historians, there’s a look back at the war-era events behind the lab’s founding. Read the rest of this entry »
Iowa Science Interface 