Science Link of the Week » Explorersweb

A passion for the natural world drives many of our adventures. And when we’re not out and about, we love finding discoveries about places to stay and travel. Here are some great natural history links we found this week.

Sharknado attitude

Shark vs. Orca: Is it rational to fear or not?: Orcas and great white sharks are among the most feared sea creatures. Statistics show that sharks are more likely to bite humans than orcas. But statistics also show that a human is more likely to bite you in the water than an orca. In fact, there has only been one documented attack on a human by a wild orca.

One reason for this is that killer whales are “found in high densities in cold, high-latitude areas. These are areas where the water is not particularly inviting for the average beachgoer,” explains marine mammal researcher Emma Locke.

In fact, regardless of the water temperature, both sharks and orcas are unlikely to bother you.

Voyager Probe: Less memory than a cell phone

Voyager spent 45 years in space: NASA’s twin Voyager probes have been in space for 45 years. They are the only probes that have explored interstellar space, the vast region of our Sun and Solar System.

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 both Uranus and Neptune. At each stop, they captured images and provided insight into previously unseen worlds.

Voyager 1 flew past the heliosphere while Voyager 2 orbited the planets. It remained 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decades in space, they are now older than many of the researchers who operate them, and much of their technology is outdated.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 probe has 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 confident that the spacecraft will provide more scientific surprises as it travels farther from Earth,” said Suzanne Dodd, project manager for Voyager at JPL.

One of the Voyager probes in the Space Simulator Chamber at NASA’s Jet Propulsion Laboratory, April 27, 1977. Photo: NASA/JPL-Caltech Photojournal

lost membrane

Evolutionary changes that helped pave the way for human speech: Scientists have discovered evolutionary differences in the human voice box compared to other primates. This difference may be the reason we can speak.

Scientists have analyzed the voice boxes of 43 species of primates. The human larynx was missing two things, the other 42 included, a vocal membrane and an air sac. The missing tissues allowed people to have long, steady speech and control the pitch of their voice.

“The more complex vocal structure in non-human primates may make it difficult to control vibrations with precision,” said primatologist Takeshi Nishimura.

A giant meteorite impact created the continents: New research suggests that the impact of a giant meteorite formed Earth’s continents. This theory has been around for decades but until recently there was very little evidence to support it.

Researchers are analyzing 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 solid evidence that the processes that formed the continents began with the impact of a giant meteorite, which was responsible for the extinction of the dinosaurs, but which happened billions of years ago,” said geologist Tim Johnson.

Small holes in a regularly repeating pattern on the seafloor.

Small holes were found in regularly repeating patterns on the sea floor. Photo: NOAA

A mystery digger

‘Alien’ holes in the ocean floor: Researchers have discovered a set of perfectly aligned holes in the seafloor. The row of holes is 2.6 kilometers below the surface and researchers don’t know where they came from.

A team of NOAA ocean explorers found an unusual pattern in the mid-Atlantic ridge, a relatively unexplored area. The holes are set in a straight line at regular intervals. A small mound 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 sediment-dwelling organisms made tiny holes, but no one had ever seen them behave this way.

“These holes were previously reported from the area but their origin remains a mystery. They look almost man-made, with small piles of sediment around the holes that look like they were excavated 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 SAvEWhales, in the Mediterranean.

In this region, ship strikes are the leading cause of death for sperm whales. The new system uses clicks to locate sperm whales with an accuracy of 30-40 meters. Tests have shown that it can quickly detect if nearby ships have time to change course or slow down to avoid whales.

The system uses a hydrophone to pick up sound. The time it takes for 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 faint click. This is the reflection of the click as it bounces off the surface of the water. After understanding this, scientists have also been able to determine the depth of the whale.

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