What is the deepest spot in the ocean? -Lawrence, 11, Philippines
rcwebberDear Lawrence,
Deep underwater, not too far from Guam, lies a crescent-shaped canyon called the Mariana Trench. It is home to the deepest known spot in the ocean: The Challenger Deep.
Read More ...Why is the ocean salty? -Alysin, 10, Ruston, La.
rcwebberDear Alysin,
At first, I thought the answer to your question might take us deep into the ocean. But it turns out the source of our salty seas is actually on land.
Read More ...If mollusks have such heavy shells to drag around with them, how have they spread all over the ocean? -Michel W.
rcwebberDear Michel,
Mollusks, from land snails and slugs to oysters and mussels in the sea, have a few things in common. They have a head. They have a soft middle part that holds their organs. Then, some have a muscle that’s known as a “foot.”
Read More ...Dr. Universe: What is something a lot of people might not know about sharks?
rcwebberIt’s Shark Week, so I made a visit to my friend Jon Mallatt. He’s a Washington State University biologist who has studied the jaws of ancient sharks.
Jon Mallatt: Some of them, such as tiger sharks, cat sharks, and even great white sharks, have quite large brains—relative to their body weight— and are intelligent. They are not “primitive” animals. The shark relatives, Manta rays and devil rays, have even larger brains than any shark.
Dr. U: How long have sharks been around, anyways?
JM: At least 420 million years and maybe 460. It is hard … » More …
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