September 3, 2013
Sagittarius A Black Hole Is A Picky Eater – The Daily Orbit
What are the dietary restrictions of a supermassive black hole?
Whales are catching some rays this summer too.
Can a goldfish beat you at “name that composer?”
And it’s a fishy kind of day on the Daily Orbit!
Hello and welcome to the Daily Orbit. I’m Emerald Robinson.
Who knew black holes were picky eaters? Researchers say they now know why supermassive black holes at the center of galaxies, or simply SMBH’s, have such low accretion rates – meaning they take in very little of the cosmic gases surrounding them. Scientists used the Chandra X-ray Space Telescope to look at the closest SMBH to us, Sagittarius A, and found that it ejects 99% of the gas it takes in because it is too hot. Winds from massive stars nearby heat up the cosmic gases making these hotter gases more difficult for the black hole to pull in. So SMBHs are not glutinous gas eaters! And here I thought they just gobbled up anything.
And whales have been catching some rays! Just as we tan, or sunburn, so do whales! New research reveals that whales get darker with sun exposure and even incur DNA damage from prolonged sun exposure as they age. Blisters discovered on whales in Mexico prompted this research, which looked at blue, sperm, and fin whales after they returned from their migration to sunnier climes. One interesting find was that darker sperm whales trigger a stress response that protects them from the sun since they spend more time near the ocean surface and receive more UV radiation – similar to the way our skin uses free radicals for sun protection. They say this is a reminder that climate change is affecting every creature on the planet. Isn’t that a whale of a tan?
Let’s play a little game of name that composer! Who is this? A. Bach B. Stravinsky? If you said Bach. You are correct! If you said, Stravinsky, well then a goldfish probably beat you to the punch on that one. Researchers in Japan trained goldfish to discriminate between the music of Bach and Stravinsky, having them bite a red bead in response to hearing one and not when hearing the other. The goldfish got it right 75% of the time – better than most of us humans. They said that the music itself doesn’t have specific meaning for the goldfish but that the ability to discriminate such complex sound does. Don’t feel bad, “goldie” beat me too!
Goldfish that can discern Bach and now frogs that hear with their mouths? Science never ceases to amaze me. Researchers say that Gardiner’s frogs, found on the Seychelles Islands off the coast of Africa, use their mouth cavity and tissue to transmit sound to their inner ears. These frogs, unlike other animals and even most other frogs, do not possess a middle ear, which is typically required for hearing. Numerical simulations and X-ray imaging showed that sounds travel through the oral cavity to the tiny frog’s inner ear due to reduced thickness of tissue and a smaller number of tissue layers between the mouth and inner ear. So it’s a combination of mouth cavity and bone conduction that lets these seemingly deaf frogs hear!
Well, it’s all about fish and frogs today! Back to fish. Scientists have discovered a new species of shark living in the waters of Indonesia. But this shark has swag! Wanna know why? It walks. This shark uses its fins to gently glide across the sea floor on its belly as it searches for food and a place to rest. Called the epaulette shark, it’s actually one of nine walking sharks found all over the world. The mama shark lays her eggs underneath coral ledges and then the baby sharks once born swim around slowly and use their fins to walk along the seafloor to find crustaceans and other foods. Research say this find is important because it increases interest in the marine life in Indonesia, making it less likely that these creatures will end up in shark fin soup somewhere in China.
And that’s it for the Daily Orbit!