Agriculture
Where Have All the Bees Gone?
Watering the Air
Microbes at the Gas Pump
Amphibians
Newts
Poison Dart Frogs
Bullfrogs
Animals
No Fair: Monkey Sees, Doesn't
New Elephant-Shrew
Saving Africa's Wild Dogs
Behavior
Swedish Rhapsody
Pain Expectations
Lightening Your Mood
Birds
Parrots
Woodpecker
Penguins
Chemistry and Materials
The hungry blob at the edge of the universe
A Diamond Polish for Ancient Tools
The hottest soup in New York
Computers
The Book of Life
Nonstop Robot
Programming with Alice
Dinosaurs and Fossils
Middle school science adventures
Dinosaurs Grow Up
Meet the new dinos
E Learning Jamaica
2014 GSAT Results for Jamaican Kids
E Learning in Jamaica WIN PRIZES and try our Fun Animated Games
Results of GSAT are in schools this week
Earth
Coral Islands Survive a Tsunami
Easy Ways to Conserve Water
Life under Ice
Environment
Nanosponges Soak Up Pollutants
Missing Tigers in India
Groundwater and the Water Cycle
Finding the Past
Prehistoric Trips to the Dentist
Digging Up Stone Age Art
A Long Haul
Fish
Saltwater Fish
Tiger Sharks
Perches
Food and Nutrition
Allergies: From Bee Stings to Peanuts
Recipe for Health
A Pepper Part that Burns Fat
GSAT English Rules
Finding Subjects and Verbs
Adjectives and Adverbs
Pronouns
GSAT Exam Preparation Jamaica
42,000 students will sit for the GSAT Exam in two weeks
Tarrant High overcoming the odds
Results of GSAT are in schools this week
GSAT Exams Jamaica Scholarships
GSAT Scholarship
GSAT Exam Preparation
GSAT Practice Papers | GSAT Mathematics | Maths
GSAT Mathematics
E Learning in Jamaica WIN PRIZES and try our Fun Animated Games
Secrets of an Ancient Computer
It's a Math World for Animals
Human Body
Running with Sneaker Science
Spitting Up Blobs to Get Around
Workouts: Does Stretching Help?
Invertebrates
Giant Clam
Nautiluses
Krill
Mammals
Rottweilers
Cape Buffalo
Walrus
Parents
What Not to Say to Emerging Readers
Choosing a Preschool: What to Consider
Expert report highlights the importance to parents of reading to children!
Physics
IceCube Science
Invisibility Ring
Speedy stars
Plants
Pumping Up Poison Ivy
Sweet, Sticky Science
Getting the dirt on carbon
Reptiles
Copperhead Snakes
Gila Monsters
Lizards
Space and Astronomy
Solving a Sedna Mystery
Zooming In on the Wild Sun
A Planet's Slim-Fast Plan
Technology and Engineering
Machine Copy
Algae Motors
Slip Sliming Away
The Parts of Speech
Problems with Prepositions
Pronouns
What is a Preposition?
Transportation
Robots on the Road, Again
Ready, unplug, drive
Charged cars that would charge
Weather
Weekend Weather Really Is Different
A Change in Climate
Earth's Poles in Peril
Add your Article

Holes in Martian moon mystery

The Martian moon Phobos is cratered, lumpy and about 16.8 miles long, or 3 miles longer than the island of Manhattan. According to a recent study, the moon is also unusually light. Planetary scientists found that Phobos is probably not a solid object, and that as much as 30 percent of the moon’s interior may be empty space. That doesn’t mean that Phobos is an empty shell where we could, say, set up a rest stop for spaceships on their way to the outer planets. But the new finding probably does mean that Phobos was not an asteroid that got caught in Mars’ gravity as it floated by the planet. Phobos is the larger of Mars’ two moons, and astronomers have had many ideas about where it came from. Previous studies have suggested that Phobos was an asteroid. Other studies suggest the moon formed from bits of Martian rock that were sent into space after a giant object, like an asteroid, crashed in Mars. The new study suggests that neither of these ideas is completely correct. The truth might be some combination of the two. Scientists may never know how Phobos came to be a Martian satellite, but the new study may help eliminate some possibilities, Tom Andert told Science News. Andert, who worked on the new study, is a planetary geophysicist at the University of the German Armed Forces in Munich. A planetary geophysicist is a scientist who studies physical properties, such as rocks and appearance, to understand more about celestial bodies such as planets and moons. Andert and his colleagues were able to study Phobos thanks to the Mars Express, a spacecraft that orbits Mars and takes measurements. That spacecraft left Earth in 2003 and is a project by the European Space Agency, or ESA. In March, Mars Express flew closer to Phobos than any spacecraft ever had before, ESA reports. The scientists wanted to learn the density of Phobos. Density measures how close together, on average, are the atoms in an object. If two objects are the same size but have different densities, the denser object will have more mass — which means it will feel heavier when you’re holding it on Earth. Density is found by dividing mass by volume. Since the scientists already had a good idea of the volume of Phobos, they just had to find its mass in order to figure out its density. They made their mass measurements by studying the gravitational force of Phobos. Gravity is an attractive force, which means anything with mass attracts anything else with mass. (A human body, for example, gravitationally attracts every other human body. Earth attracts those human bodies to it even more.) The more mass an object has, the stronger its gravitational force. Since a large body like the Earth has a lot of mass, it has a strong gravitational force — strong enough to hold people on its surface and the Moon in orbit. When Mars Express flew close to Phobos, the small moon’s gravity attracted the spacecraft. By studying changes in the motion of Mars Express, the scientists were able to estimate the gravitational tug of Phobos. Once they knew the strength of its gravity, they could find its mass. They found that Phobos has a density of about 1.87 grams per cubic centimeter. The rocks in the crust of Mars, for comparison, are much denser: about 3 grams per cubic centimeter. This difference suggests that Phobos is not made of rocks from the surface of Mars. Some asteroids have densities of about 1.87 grams per cubic centimeter, but Andert says that those asteroids would be broken apart by Mars’ gravity — a fact that probably rules out the possibility that Phobos was once a free-floating asteroid. Some scientists, like Tom Duxbury, don’t mind giving up the idea that Phobos was once an asteroid. “Finally we’re drifting away from the idea that the Martian moons are captured asteroids,” Duxbury told Science News. Duxbury, of George Mason University in Fairfax, Va., did not work on the new study but also studies planets. He told Science News that he’s “happy to see that Phobos and Deimos [Mars’ other moon] are getting a lot of attention these days.” POWER WORDS (adapted from the Yahoo! Kids Dictionary) gravity The natural force of attraction between any two massive bodies. It is directly proportional to the product of the objects’ masses and inversely proportional to the square of the distance between them. moon A natural satellite revolving around a planet. orbit The path of a celestial body or an artificial satellite as it revolves around another body. For example, the path of a planet as it moves around its host star. planetary geophysics The physics of planets and their environments, including the field that combines physics and geology.

Holes in Martian moon mystery
Holes in Martian moon mystery








Designed and Powered by HBJamaica.com™