For nearly as long as astronomers have been able to observe asteroids, a question has gone unanswered: Why do the surfaces of most asteroids appear redder than meteorites — the remnants of asteroids that have crashed to Earth?
In 2010, Richard Binzel, a professor of planetary sciences at MIT, identified a likely explanation: Asteroids orbiting in our solar system’s main asteroid belt, situated between Mars and Jupiter, are exposed to cosmic radiation, changing the chemical nature of their surfaces and reddening them over time. By contrast, Binzel found that asteroids that venture out of the main belt and pass close to Earth feel the effects of Earth’s gravity, causing “asteroid quakes” that shift surface grains, exposing fresh grains underneath. When these “refreshed” asteroids get too close to Earth, they break apart and fall to its surface as meteorites.
Since then, scientists have thought that close encounters with Earth play a key role in refreshing asteroids. But now Binzel and colleague Francesca DeMeo have found that Mars can also stir up asteroid surfaces, if in close enough contact. The team calculated the orbits of 60 refreshed asteroids, and found that 10 percent of these never cross Earth’s orbit. Instead, these asteroids only come close to Mars, suggesting that the Red Planet can refresh the surfaces of these asteroids.
“We don’t think Earth is the only major driver anymore, and it opens our minds to the possibility that there are other things happening in the solar system causing these asteroids to be refreshed,” says DeMeo, who did much of the work as a postdoc in MIT’s Department of Earth, Atmospheric and Planetary Sciences.
DeMeo and Binzel, along with former MIT research associate Matthew Lockhart, have published their findings in the journal Icarus.
The ravages of deforestation, wildfires, windstorms, and insects on global forests are revealed in unprecedented detail in a new study based on data from Landsat satellites. Researchers developed new mapping tools that are the first to document forest loss and gain at high resolution and with a consistent method around the globe. The maps will allow scientists to compare forest changes in different countries and to monitor annual deforestation.
Since each pixel in a Landsat image shows a 30-meter square of land—an area about the size of a baseball diamond—researchers can see enough detail to tell local, regional, and global stories. University of Maryland researcher Matthew Hansen and colleagues analyzed 143 billion pixels in 654,000 Landsat images to compile maps of forest loss and gain between the years 2000 and 2012. Key to the project was a collaboration with a team from Google Earth Engine, who took the models developed at the University of Maryland for processing and characterizing the Landsat data and reproduced them in the Google Cloud. Years of data processing was reduced to days.
In many workplaces, wearing the same outfit as your coworkers would come off as a bit strange. Not so if you happen to be in Antarctica as part of Operation IceBridge. In the photograph below, IceBridge team member Theresa Stumpf, right, and other passengers have just arrived on McMurdo's sea ice runway. They touched down on Nov. 12, 2013 aboard a U.S. Air Force C-17 transport aircraft. In past years, IceBridge campaigns were based in Punta Arenas, Chile. Flying from McMurdo this year will make it possible for the team to survey areas they couldn't during previous missions.
A lot has been said over the years about the best ways to protect your machine from attacks and malicious code. But where do those recommendations intersect with ways to protect your friends from attacks? By failing to protect your own data, you’re sometimes putting them at risk as well. Here are a few ways people end up mindlessly spreading the malware love. USB sticks are considered an infection vector unto themselves, as many Windows-based threats will attempt to run automatically upon inserting the drive. While it may not affect you, it may get your friends.
mySchoolNotebook.com is an application for taking school notes and sharing them with friends. Say no to heavy and expensive notebooks, disorganized notes, and missing notes from classes you couldn’t attend. MySchoolNotebook.com allows you to take notes into well-organized notebooks divided into individual topics with automatically numbered classes and share them instantly with your friends. Other features: Easy sign-in via Facebook account or e-mail registration, Drawing tool, File upload, Printing of notes, Conversion to PDF, Recording and taking of pictures in iOS version, Offline version - no Internet, Connection needed, Search engine. MySchoolNotebook.com mainly supports Google Chrome, Apple Safari, and Firefox 4. We will try to broaden the number of supported browsers to Opera and Microsoft Internet Explorer 9+. Offline mode works in Google Chrome, Apple Safari, and also Opera in the future. Other browsers do not support used technology.