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The Speed of Sound on Mars Is Strangely Different, Scientists Reveal

Scientists have confirmed the speed of sound on Mars, using equipment on the Perseverance rover to study the red planet’s atmosphere, which is very different to Earth’s.

What they discovered could have some strange consequences for communication between future Martians.

The findings suggest that trying to talk in Mars’ atmosphere might produce a weird effect, since higher-pitched sound seems to travel faster than bass notes. Not that we’d try, since Mars’ atmosphere is unbreathable, but it’s certainly fun to think about!

Scientists identify neurons in the brain that drive competition and social behavior within groups

Li and his colleagues found that the animals’ social ranking in the group was closely linked to the results of competition, and by examining recordings from neurons in the brains of mice in real time, the team discovered that neurons in the anterior cingulate region of the brain store this social ranking information to inform upcoming decisions.

“Collectively, these neurons held remarkably detailed representations of the group’s behavior and their dynamics as the animals competed together for food, in addition to information about the resources available and the outcome of their past interactions,” explains senior author Ziv M. Williams, MD, a neurosurgical oncologist at MGH. “Together, these neurons could even predict the animal’s own future success well before competition onset, meaning that they likely drove the animals’ competitive behavior based on whom they interacted with.”

Manipulating the activity of these neurons, on the other hand, could artificially increase or decrease an animal’s competitive effort and therefore control their ability to successfully compete against others. “In other words, we could tune up and down the animal’s competitive drive and do so selectively without affecting other aspects of their behavior such as simple speed or motivation,” says Williams.

This Wild Rocket Could Help Make Hypersonic Travel a Reality

To develop the hypersonic vehicles of the future, we need to properly understand how to predict boundary layer transition on realistic vehicle shapes and what the minute effects of turbulent flow on hypersonic vehicles are. Data from the BOLT II flight experiment will help do just that.


Both the BOLT and BOLT II vehicles have a complex, swept geometry with a concave surface to represent a real hypersonic vehicle. The aim is to produce complex, real-world data that engineers and scientists can use to improve their models for predicting transition on hypersonic vehicles.

A separate experiment is run on each side of the vehicle, with one “smooth” side and one “rough” side. The flow running length along the vehicle is 1 meter, slightly larger than the original BOLT vehicle.

BOLT II will be launched on a suborbital trajectory by a two-stage sounding rocket. During its ascent, it is planned to reach Mach 6, where an ascent flight experiment will occur. It will turn over in space and then re-enter the atmosphere, before performing a descent experiment at Mach 5.5.

Brick And Motor Table Saw Delivers Paper Cuts On Demand

Twenty Two Motors. Fifty gears. Eighty Two Hundred RPM. Hundreds of individual pieces, and one sheet of glossy paper cut into a disk. This isn’t a nightmare driven Rube Goldberg machine. Instead, it’s a Lego monstrosity created by [GazR] of [GazR’s Extreme Brick Machines!], and all of these parts are flying in formation for one Lego slicing purpose. In the video below the break, you can see what very well may be the worlds most powerful Lego and Paper table saw.

Starting out with a build that had a mere fourteen motors in a platform that looked quite a lot more like a table saw, [GazR] learned that having only fourteen motors turning a Lego based blade was not a good combination. In the next iteration, the same number of motors were used, but the gearing was increased to bring RPM up, and a Lego toy saw blade took care of cutting duties.

Seeing that higher speeds with thinner blades was a winning trend, [GazR] stepped it up to the aforementioned 8,200 RPM twenty-two motored paper whirling Lego Death Machine. Yes, [GazR] cut Lego, carrots, carpet, and paper-all with circular sheet of paper.

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