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goal was to find a star just before it ended its life

a binary star system located in M51 produced just the results they were looking fo

ne star dropped amplitude just a short period of time before the other exploded

Maybe stars give off a clear signal of impending doom, maybe they don’t

But we’ll learn something new about dying stars no matter the outcome

it was a binary star system being studied by the OSU team

consisted of both a blue and red star

At this point, the astronomers surmise the red star was the one that dimmed significantly over the three-year period while the blue one blew its top

reviewing the LBT data

when compared with Hubble images, the red star dimmed at about 10% over the final three-year period at an estimated 3% per previous years

researchers surmise the red star may have actually survived the supernova event

After the light from the explosion fades away, we should be able to see the companion that did not explode

distribution of mass, and perhaps how large the core might be

the rover won't sleep

, it will investigate the rocks at Greeley Haven, take panoramic photos of its surroundings

most important — send radio signals back to Earth.

mission team will track those signals

using Opportunity's motion relative to Earth as a proxy for the rotation of Mars

Scientists should thus be able to get very precise measurements of the planet's spin.

learning how Mars' spin axis has changed, or precessed, since NASA's Viking mission made similar measurements back in the mid-1970s

Knowing the precession rate should allow scientists to get a much better handle on the Red Planet's interior structure

keen to study Mars' nutation, which is a smaller-period variation in the planet's rotation. Such information might help reveal whether the Red Planet's core is solid or liquid

mission team will be tracking Opportunity's radio signals almost daily. After three to six months, researchers expect to have enough data to start getting an in-depth picture of the Martian interior

Ethologist

and her colleagues had hung underwater microphones in the tank because little is known about what dolphins sound like at night

One night, they suddenly heard 25 new sounds (see below) that the dolphins had never made before

dolphins are known for mimicry

researchers examined their complex daytime environment to determine

zeroed in on the new soundtrack that Planète Sauvage was playing during performances

included music, sea gulls' calls, the dolphins' own whistles, and humpback whale calls

researchers used a computer program to compare auditory recordings of the whale

showed that the two sounds were very similar

the dolphins had been captive their entire lives, they couldn't have picked them up from real whales

the team asked 20 human volunteers to listen to humpback whale sounds and wild dolphin sounds

researchers played the nighttime vocalizations and asked the volunteers whether the sounds came from a whale or a dolphin

About 76% of the time, the volunteers classified the imitations as sounds from real whales

Because the dolphins didn't make these noises during the show, the finding suggests that they waited to practice the sounds hours later.

the shows prime the animals to learn and remember information

find out whether the dolphins are asleep and dreaming when they mimic

dreams help dolphins etch new information into their memories, just like in humans

capture electroencephalogram recordings of the dolphins' brains at night

a biologist at the University of St. Andrews in the United Kingdom who studies animal vocalization, says that the idea that dolphins might delay their rehearsals for hours is intriguin

isn't convinced from the small number of recordings that the researchers obtained that the dolphins were imitating whales

dolphins make so many different sounds that it's difficult to pin down one as an imitation of a particular source

songbirds rehearse their imitations of other noises at night, so he thinks it's not unlikely that dolphins might do the same.

huge pieces of space junk could rain down on us at any moment.

Phobos-Grunt spacecraft

re-enter the atmosphere sometime between Saturday and Monday (Jan. 14 to Jan. 16).

the third uncontrolled satellite re-entry in four months

claims are handled on a case-by-case basis, you might be surprised to learn damage from satellite debris, aka space junk, likely would be covered under most insurance policies

Farmers Insurance, aired a commercial during this winter's college football bowl games offering similar assurances to its current and potential customers.

Experts predict that Russia's failed Mars probe Phobos-Grunt will crash back to Earth in mid-January 2012. This artist's concept shows fuel burning from a ruptured fuel tank as the spacecraft re-enters the atmosphere.CREDIT: Michael Carroll

NASA estimates that our planet's orbital debris cloud contains more than 500,000 pieces larger than a marble and more than 20,000 at least as big as a softball

space junk poses little threat to people on the ground. Most pieces of falling satellites burn up the atmosphere

the bits that make it through are likely to land harmlessly in the ocean or on uninhabited land

To date, nobody is known to have been injured by a chunk of falling debris.

poses a real threat to the craft that orbit and observe our planet and provide navigation and telecommunications services

2009, for example, the Iridium 33 communications satellite was destroyed when it slammed into a defunct Russian satellite.

This computer illustration depicts the density of space junk around Earth in low-Earth orbit.CREDIT: ESA

Bullet integrates readings from the gyro and accelerometer using a complementary filter. To balance, the angle estimate is fed through a PID loop (with no integral term). The loop runs at 625 Hz. The output from this stage determines the duty cycle of a 1.22 kHz PWM signal, which is connected to the H-bridge. The code was written in C, and is in the public domain.

It took me several hours to be able to ride in a straight line without crashing, and it took several days to learn how to turn in a controlled manner. Many of my friends have tried riding it, usually with little success (including some actual unicyclers).

I am certainly not the first person to build an electric unicycle. Perhaps the most well-known self-balancing unicycle is Trevor Blackwell's Eunicycle, which also uses the OSMC. His design is similar to mine, but uses a much more expensive battery pack ($218 for his vs $44 for mine). Also, the Eunicycle's motor and gearbox cost a grand total of $644, whereas Bullet's drive system (including the wheel itself) was $195. Finally, the IMU he uses is about $100 more than mine. Overall, Bullet is several hundred dollars cheaper than the Eunicycle, but this comes at a price (mostly weight).