anônimo perguntou:

why does your breath smell bad when you wake up?

Warning: this is gross.

It’s because colonies of bacteria have been growing in your mouth all night.

Bacteria really love the inside of the human body, and your mouth is no exception. Saliva normally keeps things under control by sweeping away bacteria and the food particles they eat. But at night, when you aren’t producing as much saliva, your mouth becomes a prime breeding ground. As the colonies grow, more and more bacteria feast on food particles and dead cells, producing a bunch of different odor-causing compounds as waste products – like one called cadaverine. 

So when you say your mouth smells like a corpse in the morning… that’s not really an exaggeration.

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Google honors Sally Ride

May 26th is the birthday of Sally Ride, who was an American physicist and astronaut. She was the first American woman and the youngest American astronaut to travel space. She also served on the committees that investigated the Challenger and Columbia space shuttle disasters, being the only person to participate on both.

Ride was also the first known LGBT astronaut.

Sally Ride passed away July 23, 2012, at the age of 61.

At 700 meters or more below the surface of the ocean, the lack of sunlight means food can be hard to come by. Some animals address the problem by eating extra-big meals that they swallow whole to make sure they don’t miss even a piece of their prey. One species, the black swallower, can gulp down a fish 10 times its own weight and up to four times its length. Two rows of large, pointed teeth on each jaw can collapse to make room as prey ratchets down the gullet, to be slowly digested in a stomach with expandable walls.

Meet more creatures in Life at the Limits: Stories of Amazing Species, open now through January 2016.

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photos by harun mehmedinovic from arizona’s vermillion cliffs national monument and grand canyon national park. the former hosts some of the most unique landscapes on the planet, from its ferrous coloured petrified sand dunes, smoothed and wave like from ancient flash flooding (and hence known as the wave), to the jurassic era petrified sandstone of white pocket, known for it’s so called cauliflower rocks, formed as sand was lithified into rock from ancient earthquakes (hence ‘sandstone’). 

From this carefully chosen perspective in Salamanca, Spain, photographer César Vega Toledano lines branches of a tree to be continuous with dust lanes in our Milky Way galaxy. It’s an incredible composition. 

But what I personally love about the perspective of this picture is that it reminds me of our place within the Milky Way. I get a sense of orbit, not around the Sun but around the center of our galaxy. It can be easy to forget that we are in a remote corner of a massive collection of stars and dust measuring 100,000 light years across. Traveling at an average speed of 515,000 mph, it takes the Sun about 250 million years to complete one rotation around the Milky Way’s core. The last time the Solar System was in this position, there were dinosaurs on Earth. The scales are unfathomable to our everyday experiences. Astronomy is so incredibly humbling.

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A reaction wheel  is a type of flywheel used primarily by spacecraft for attitude control without using fuel for rockets or other reaction devices. They are particularly useful when the spacecraft must be rotated by very small amounts, such as keeping a telescope pointed at a star. They may also reduce the mass fraction needed for fuel. This is accomplished by equipping the spacecraft with an electric motor attached to a flywheel which, when its rotation speed is changed, causes the spacecraft to begin to counter-rotate proportionately through conservation of angular momentum.

though similar, it is not to be confused with a gyroscope.

When Will We See an Actual Dino-Chicken?

Talk of a “chickenosaurus” lit up the science world last week when researchers announced they had modified the beak of a chicken embryo to resemble the snout of its dinosaur ancestors. But although some experts have lauded the feat, a beak is just one of many modifications needed to revert a chicken into a dinosaur.

Given these obstacles, how close are scientists to creating a dino-chicken? Learn here