A passion for the natural world drives many of our adventures. And when we’re not out and about, we love delving into discoveries about 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 the fear reasonable?: Orcas and great white sharks are among the most fearsome creatures of the ocean. 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 an orca. In fact, there is only one documented case of a wild orca attacking a human.
One of the reasons for this is that killer whales “tend to be found in higher densities around cold, high-latitude regions. These are areas where the water is not particularly attractive to the average beachgoer,” explains marine mammal researcher Emma Luck.
Indeed, regardless of the water temperature, both sharks and orcas are unlikely to bother you.
Voyager probes: less memory than a mobile phone
Voyager records 45 years in space: NASA’s twin Voyager probes have now been in space for 45 years. They are the only probes to have explored interstellar space, the vast region through which the sun and our solar system travel.
NASA launched Voyager 2 on August 20, 1977, and Voyager 1 16 days later on September 5. They first went to Saturn and Jupiter. Voyager 2 then became the first and only spacecraft to approach Uranus and Neptune. At each stop, they captured images and provided insight into previously unseen worlds.
While Voyager 2 circled the planets, Voyager 1 went to 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decades in space, they are now older than many of the researchers who operate them, and much of their technology is outdated.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 for how long mission will continue, but we can be sure that the spacecraft will offer more scientific surprises as they travel further from Earth,” said Suzanne Dodd, project manager for Voyager at JPL.
One of the Voyager probes in the Space Simulator Room at NASA’s Jet Propulsion Laboratory, April 27, 1977. Photo: NASA/JPL-Caltech Photojournal
A missing membrane
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 why we can talk.
Scientists analyzed the voice boxes of 43 primate species. The human larynx lacked two things that the other 42 contained, a vocal membrane and an air sac. The missing tissue has allowed people to make long, sustained speech and control the pitch of their voices.
“The more complicated vocal structures in non-human primates may make it difficult to control vibrations accurately,” said primatologist Takeshi Nishimura.
The giant meteorite impact 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.
The researchers analyzed zircon crystals from the Pilbara Craton in Western Australia. They are the best-preserved remnants of Earth’s ancient crust. The composition of oxygen isotopes in the crystals is similar to that found at giant meteorite impact sites.
“Our research provides the first strong evidence that the processes that ultimately formed the continents began with giant meteorite impacts, similar to those responsible for the extinction of the dinosaurs, but which occurred billions of years ago,” said geologist Tim Johnson.
Small holes found in a regularly repeating pattern on the bottom of the sea. Photo: NOAA
A mystery digger
‘Alien’ holes in the ocean floor: Researchers have discovered a group of perfectly aligned holes on the sea floor. The row of holes is 2.6 km below the surface and researchers have no idea where they came from.
The team on the NOAA Oceans Explorer 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 holes found in the area in 2004 by two marine scientists. At the time, scientists proposed that an organism living in the sediment made the tiny holes, but no one had ever seen anything behave this way.
“These holes have previously been reported from the region, but their origin remains a mystery. While they look almost man-made, the small piles of sediment around the holes make them look like they were dug by…something,” NOAA researchers said.
New detection system could save whales from ship strikes: A research team in Greece has developed a new system for detecting whales. They are testing the prototype, known by the acronym SAvEWhales, in the Mediterranean Sea.
In this area, the main cause of death of sperm whales is ship strikes. The new system uses sperm whale clicks to detect their location with an accuracy of 30-40m. Testing has shown it can detect it so early that nearby ships would have time to alter their course or slow down to avoid the whales.
The system uses hydrophones to capture 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 realized they could hear a second, fainter click. It is the reflection of the click as it bounces off the surface of the water. Once they realized this, scientists were also able to calculate the depth of the whale.