Passion for the natural world drives many of our adventures. And when we’re not out and about, we love delving into the discoveries of the places we live and travel. Here are some of the best natural history links we found this week.
The Sharknado attitude
Shark vs Orca: Is Fear Rational?: Orcas and great white sharks are among the most feared ocean creatures. Statistics show that a shark is more likely to bite a human than an orca. But statistics also show that a person is more likely to bite you in the water than a killer whale. In fact, there is only one documented case of a wild killer whale attacking a human.
One reason for this is that killer whales “tend to be found in higher densities around cold, high-latitude regions. These are areas where the water isn’t particularly attractive to the average beachgoer. ” explains marine mammal researcher Emma Luck.
In fact, regardless of the water temperature, both sharks and killer whales are incredibly unlikely to bother you.
Voyager probes: less memory than a mobile phone
Voyager marks 45 years in space: NASA’s twin Voyager probes have been in space for 45 years. They are the only probes to have explored interstellar space, the vast region through which our sun and solar system travel.
NASA launched Voyager 2 on August 20, 1977, and Voyager 1 16 days later on September 5. First they went to Saturn and Jupiter. Voyager 2 then became the first and only spacecraft to approach both Uranus and Neptune. At each stop, they captured images and provided a glimpse into never-before-seen worlds.
As Voyager 2 circled the planets, Voyager 1 reached the edge of the heliosphere. He stayed there until 2012 and discovered that the heliosphere blocks 70% of the cosmic rays emitted by exploding stars.
After decades in space, they are now older than many of the researchers who operate them, and much of their technology is outdated. The probes have three million times less memory than a modern cell phone. Despite this, they are still at the forefront of space exploration.
“We don’t know how long mission will continue, but we can be sure that the spacecraft will deliver more scientific surprises as they travel farther from Earth,” said Suzanne Dodd, Voyager project manager at JPL.
A membrane is missing
The evolutionary change that helped pave the way for human speech: Scientists have discovered evolutionary differences in the voice boxes of humans compared to other primates. This difference may be the reason why we can talk.
The scientists analyzed the voice boxes of 43 primate species. The human larynx lacked two things that contained the other 42, a vocal membrane and an air sac. The missing tissues have allowed humans to make long, steady speech and control the pitch of their voices.
“The more complicated vocal structures of non-human primates may make it difficult to control vibrations precisely,” said primatologist Takeshi Nishimura.
The impact of giant meteorites created the continents: New research suggests that giant meteorite impacts formed Earth’s continents. This theory has been around for decades, but until recently there was very little evidence to support it.
Researchers have been analyzing zircon crystals from the Pilbara Craton in Western Australia. They are the best preserved remains of the ancient earth’s crust. The oxygen isotope composition of the crystals is similar to that found at giant meteorite impact sites.
“Our research provides the first strong evidence that the processes that eventually formed the continents began with giant meteorite impacts, similar to those responsible for the extinction of the dinosaurs, but occurring billions of years earlier.” said geologist Tim Johnson.
A mystery digger
“Alien” holes in the ocean floor: Researchers have discovered a set of perfectly aligned holes in the seabed. The row of holes is 2.6 km below the surface and researchers have no idea where they came from.
The NOAA Oceans Explorer team found the unusual pattern in the mid-Atlantic Ridge, a relatively unexplored region. The holes are placed in a straight line at regular intervals. A small pile of sediment surrounds each hole. They are similar to the holes found in the area in 2004 by two marine scientists. Scientists then proposed that an organism living in the sediment made the tiny holes, but no one has seen anything behaving this way.
“These holes have been previously reported from the region, but their origin remains a mystery. Although they appear almost man-made, the small mounds of sediment around the holes make them appear to have been dug by … something,” NOAA researchers said.
New detection system could save whales from ship strikes: A research team in Greece has developed a new whale detection system. They are testing the prototype, known by the acronym SAvEWhales, in the Mediterranean Sea.
In the area, the main cause of death of sperm whales is ship strikes. The new system uses the sperm whale’s clicks to detect its location with an accuracy of 30-40m. Tests have shown it can detect this early enough to give nearby ships time to alter their course or slow down to avoid the whales.
The system uses hydrophones to pick up the sounds. The time it takes for the sound to reach the various hydrophones allows the system to calculate the whale’s position. For each click, the scientists noticed they could hear a second, fainter click. It is the reflection of the click when it bounces on the surface of the water. After realizing this, scientists were also able to calculate the depth of the whale.