WHY THE TRIASSIC????

March 2015 Solar Eclipse by NASA Goddard Photo and Video

Tarantula Nebula by NASA Hubble

Asimov invented the three laws of robotics and spent most of his robot books pulling them apart and exploring why they wouldn’t work but why they couldn’t really be improved, either.

Most robot revolution stories assume the danger is when robots stop obeying us and start thinking for themselves.

Asimov’s stories suggest that the real danger is robots doing exactly what we tell them to.

I think that’s both more realistic and actually scarier.

M42 by NASA Hubble

What if oxygen is poisonous and it just takes 75-100 years to kill us?

I’ve just made a behavioral study on birds (aka. I’ve fed bread to pigeons and crows) and I’d like to conserve the results for posterity:

Pigeons can and will fight each other for even the smallest crumb of bread

When a pigeon picked up a bread crumb and other pigeons are nearby it will spread its wings to ensure the other pigeons can’t get close enough to steal the crumb™

The other , bread stealing pigeons might also spread their wings to make sure that no pigeon can steal the breadcrumb before them

They will steal it straight from another pigeons beak

Pigeons have no manners

They WILL fly at you and hover around your head once they realized you’re the one throwing the crumbs

They have no concept of personal space.

Crows on the other hand are civilized.

They will try to get to the crumb first but when another crow has reached the crumb before them they will accept this and leave them be

However if a pigeon reaches the crumb first they WILL go absolutely feral and peck the pigeon until it surrenders the crumb

Pigeons are reasonably scared of crows and won’t try to steal crumbs from their very pointy stabby beaks

Crows will wait for you to throw the crumbs at an appropriate distance because they do have manners

Unlike pigeons they will also watch you and look right into your eyes, expectantly

If a crow looks at you , waiting, and you throw it a crumb it will try to catch it just like a dog would

Pigeons however don’t notice shit until it lies in front of their face or they see another pigeon found something

Crows understand pointing, pigeons don’t

If the crows are satisfied they will fly away

Pigeons are never satisfied and therefore will bother you until the very end (aka. Until you don’t have any bread left)

They always hunger.

In conclusion:

Feeding crows is more fun than feeding pigeons because crows know the rules of society and pigeons don’t.

(Next Time on “birdhavioral studies” : “why seagulls fear neither god nor devil” )

The Stellar Buddy System

Our Sun has an entourage of planets, moons, and smaller objects to keep it company as it traverses the galaxy. But it’s still lonely compared to many of the other stars out there, which often come in pairs. These cosmic couples, called binary stars, are very important in astronomy because they can easily reveal things that are much harder to learn from stars that are on their own. And some of them could even host habitable planets!

The birth of a stellar duo

New stars emerge from swirling clouds of gas and dust that are peppered throughout the galaxy. Scientists still aren’t sure about all the details, but turbulence deep within these clouds may give rise to knots that are denser than their surroundings. The knots have stronger gravity, so they can pull in more material and the cloud may begin to collapse.

The material at the center heats up. Known as a protostar, it is this hot core that will one day become a star. Sometimes these spinning clouds of collapsing gas and dust may break up into two, three, or even more blobs that eventually become stars. That would explain why the majority of the stars in the Milky Way are born with at least one sibling.

Seeing stars

We can’t always tell if we’re looking at binary stars using just our eyes. They’re often so close together in the sky that we see them as a single star. For example, Sirius, the brightest star we can see at night, is actually a binary system (see if you can spot both stars in the photo above). But no one knew that until the 1800s.

Precise observations showed that Sirius was swaying back and forth like it was at a middle school dance. In 1862, astronomer Alvan Graham Clark used a telescope to see that Sirius is actually two stars that orbit each other.

But even through our most powerful telescopes, some binary systems still masquerade as a single star. Fortunately there are a couple of tricks we can use to spot these pairs too.

Since binary stars orbit each other, there’s a chance that we’ll see some stars moving toward and away from us as they go around each other. We just need to have an edge-on view of their orbits. Astronomers can detect this movement because it changes the color of the star’s light – a phenomenon known as the Doppler effect.

Stars we can find this way are called spectroscopic binaries because we have to look at their spectra, which are basically charts or graphs that show the intensity of light being emitted over a range of energies. We can spot these star pairs because light travels in waves. When a star moves toward us, the waves of its light arrive closer together, which makes its light bluer. When a star moves away, the waves are lengthened, reddening its light.

Sometimes we can see binary stars when one of the stars moves in front of the other. Astronomers find these systems, called eclipsing binaries, by measuring the amount of light coming from stars over time. We receive less light than usual when the stars pass in front of each other, because the one in front will block some of the farther star’s light.

Sibling rivalry

Twin stars don’t always get along with each other – their relationship may be explosive! Type Ia supernovae happen in some binary systems in which a white dwarf – the small, hot core left over when a Sun-like star runs out of fuel and ejects its outer layers – is stealing material away from its companion star. This results in a runaway reaction that ultimately detonates the thieving star. The same type of explosion may also happen when two white dwarfs spiral toward each other and collide. Yikes!

Scientists know how to determine how bright these explosions should truly be at their peak, making Type Ia supernovae so-called standard candles. That means astronomers can determine how far away they are by seeing how bright they look from Earth. The farther they are, the dimmer they appear. Astronomers can also look at the wavelengths of light coming from the supernovae to find out how fast the dying stars are moving away from us.

Studying these supernovae led to the discovery that the expansion of the universe is speeding up. Our Nancy Grace Roman Space Telescope will scan the skies for these exploding stars when it launches in the mid-2020s to help us figure out what’s causing the expansion to accelerate – a mystery known as dark energy.

Spilling stellar secrets

Astronomers like finding binary systems because it’s a lot easier to learn more about stars that are in pairs than ones that are on their own. That’s because the stars affect each other in ways we can measure. For example, by paying attention to how the stars orbit each other, we can determine how massive they are. Since heavier stars burn hotter and use up their fuel more quickly than lighter ones, knowing a star’s mass reveals other interesting things too.

By studying how the light changes in eclipsing binaries when the stars cross in front of each other, we can learn even more! We can figure out their sizes, masses, how fast they’re each spinning, how hot they are, and even how far away they are. All of that helps us understand more about the universe.

Tatooine worlds

Thanks to observatories such as our Kepler Space Telescope, we know that worlds like Luke Skywalker’s home planet Tatooine in “Star Wars” exist in real life. And if a planet orbits at the right distance from the two stars, it could even be habitable (and stay that way for a long time).

In 2019, our Transiting Exoplanet Survey Satellite (TESS) found a planet, known as TOI-1338 b, orbiting a pair of stars. These worlds are tricker to find than planets with only one host star, but TESS is expected to find several more!

Want to learn more about the relationships between stellar couples? Check out this Tumblr post: https://nasa.tumblr.com/post/190824389279/cosmic-couples-and-devastating-breakups

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

Burst of Celestial Fireworks

Postcard by Charles R. Knight

The Ammonoids The Ammonoids are a subclass of cephalopods that inhabited the oceans from the Devonian some 416 million years ago until they went extinct some 65 million years ago. The species evolved and dispersed rapidly around the world and so are some of the best guide fossils for dating the strata in which they are found.

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