Big asteroid created Fear and Panic

Mars has two moons; Phobos and Deimos. Now, Pascal Rosenblatt and his team think that the planet used to have way more moons, as they publish in this week’s Nature.

Fear and Panic; Phobos and Deimos

Scientists used to think that Phobos and Deimos, Mars’s moons, are two asteroids that got stuck in Mars’s gravity. This also made sense, since the asteroid belt is close to Mars. Moreover, the moons have an irregular shape and are not made of the same stuff as Mars. These are also clear signs that Phobos and Deimos originally were asteroids. There’s only one problem. When an asteroid gets caught in the gravity field of a planet, its orbit is usually elliptical, oval shaped. This is because the asteroid is shooting through a bit before being pulled back by the planet, this creates the oval shape. But, Phobos’s and Deimos’s orbits are circle shaped. And Mars’s gravity is way too weak to turn an oval orbit into a circular orbit. The chances that the circular orbits happened by accident are so small that it is more likely that Phobos and Deimos formed in another way, closer to Mars.

A big boom results in some moons

Pascal Rosenblatt and his team believe that Phobos and Deimos are formed out of debris that was formed when a giant asteroid hit Mars. That debris then formed a ring around Mars, and with computer simulations, Rosenblatt and his team found out that a couple of moons were formed out of that debris. All those moons, except two, orbited too close to Mars and crashed into the surface. The other two moons slowly moved into higher orbits and eventually became what we now know as Phobos and Deimos. We have, of course, no way to check this. Since we can’t just travel back in time and take a look. But if Phobos and Deimos are made out of a little bit of Mars and a bit of asteroid, it would pretty much prove this theory right.

The Borealis basin is the orange area on the left

Solving our puzzle

But there’s also another thing this new theory can explain. If an asteroid collided with Mars, there must be a crater. Rosenblatt and his team might even have found this crater already; the Borealis basin, a crater that covers around forty percent of the surface of Mars. The collision that created this crater must also have created a lot of debris, out of which the two moons and more could have easily formed. And at the same time, this new theory about Mars’s moons is another piece in the puzzle that is our solar system, and we might even be able to solve the complete puzzle one day.

Click here to read more about astronomy.

Click here to read more about physics.

Sources:

https://en.wikipedia.org/wiki/North_Polar_Basin_(Mars)

https://nl.wikipedia.org/wiki/Rochelimiet

http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2742.html

http://sci-hub.bz/10.1038/ngeo2742

http://3.bp.blogspot.com/-6JUeVSMTbcw/VBRRLmP5GBI/AAAAAAAAAMY/qksoMCv8EiA/s1600/Elliptical%2BOrbits.png

http://science.intellichristian.com/images/phocagallery/planets/mars/Mars.jpg

Closing the hole

The ozone hole poses a threat to, among others, the health of people in especially Australia. As UV light doesn’t get blocked out anymore. Fortunately, the hole seems to be closing now.

Your fridge is evil

the ozone hole

The main cause of the ozone hole are chemicals called CFCs. These chemicals were used in almost everything in the seventies; spray cans, refrigerators, Styrofoam and cleaning products. The reason for this is that CFCs don’t react easily with other chemicals. Which is really useful in, for instance, deodorant, as they won’t react with it make it smell like rotten eggs, for example. The problem however is that CFCs do react with ozone, the chemical in our atmosphere that keeps out the UV-rays and keeps us all nice and safe on earth. Without ozone, life on earth would be impossible. So this great amount of CFCs in our atmosphere have caused a ‘hole’ in the ozone layer to form above Antarctica every Australian spring. Well, not really a proper hole, it’s more of a local decrease in the concentration of ozone. As soon as scientists discovered this consequence, CFCs were forbidden, although there has always been doubt that this rule, which is called the Montreal Protocol, would have any effect. Susan Solomon and her team have found out that the rule has worked and the ozone hole is in fact closing.

Save the ozone

Although the ozone hole grew last year because of a couple of volcanic eruptions, since volcanoes can release chemicals that react with ozone too, scientists believe that the ozone hole is really shrinking and the Montreal Protocol really works. Susan Solomon and her team have studied the ozone hole with weather balloons and satellites and they analysed the amounts of CFCs and volcanic chemicals that are still floating around in the atmosphere above Antarctica. From this, the scientists conclude that the ozone hole is really shrinking.

Bye, bye skin cancer

This means that the high amounts of UV-radiation in Australia and on Antarctica will decrease. And since too much UV-radiation causes sunburn and skin cancer, this is really good news for the people living in Australia. The consequences of the ozone hole weren’t that severe on Antarctica, since not many people live there and not much sunlight, and with that not much UV-light reaches the continent. But it’s also really good news for the rest of the world, because this discovery proves that we can actually revert the harm we do to the environment with rules and laws, in this case with the Montreal Protocol. Maybe we can reverse the enhanced greenhouse effect too!

Click here to read more chemistry posts.

Sources:          

https://en.wikipedia.org/wiki/Ozone_depletion#Consequences_of_ozone_layer_depletion

http://science.sciencemag.org/content/early/2016/06/30/science.aae0061

http://www.milieuloket.nl/9353000/1/j9vvhurbs7rzkq9/vhurdyxq2n74        

https://nl.wikipedia.org/wiki/Gat_in_de_ozonlaag#Gevolgen

http://nieuws.weeronline.nl/wp-content/uploads/2014/09/18-9-2014-13-17-43.png

http://i.dailymail.co.uk/i/pix/2012/10/12/article-2216238-0B6B803000000578-298_634x420.jpg

Hairy shells and feathers

What do your hair and a turtle’s shell in common? An ancestor. Nicolas Di-Poï and Michel Milinkovitch have found the common ancestor of hair and shells.

Archaeopteryx

No missing-link

A common origin of shells and hair used to be quit a controversial idea. There are a couple of reasons for this. Firstly, no proper ‘missing-link’ has been found. There is no trace of fossils that had a skin covered with something between shells and hair. When such a missing link is found, it’s usually a strong sign that the two traits, shells and feathers for example, have a common origin. So did the dinosaur Archaeopteryx, which is basically half dinosaur half bird, prove that birds originate from dinosaurs. Another problem for the feathers, hair and shells is the fact that these three things are very different in their chemical make-up. It’s a bit like trying to find a common origin for your cat and your bed. These two things are the reason that scientists have thought that hairs and shells evolved independently of each other for a long time. Two scientists have discovered that this assumption is wrong.

Looking at baby crocodiles

Bearded dragon

Nicolas Di-Poï and Michel Milinkovitch have discovered this common origin by studying the embryos of crocodiles, snakes and bearded dragons. They analysed the unborn animals at different stages and with this, they were able to find out how the shells developed. From this discovery, they concluded that shells, hair and feathers are homologous. That means that they have a common origin, like your arms and a dolphin’s front fins have too, although they don’t look the same. Hair and feathers are formed from an earlier stage of shells because of special proteins called signalling proteins. These proteins are formed by DNA and they influence the growth of, in this case, shells. Different animals have different DNA, so they form different proteins, which changes if they have either feathers, hair or shells. And that’s why you’ll never see a hairy turtle.

One big family

This discovery tells us more about the origin of reptiles, mammals and birds, and how they’re all related. And, while a missing link between hair and shells hasn’t been found yet, it’s pretty sure that one must exist because of this new discovery. That is, however, a thing for archaeologists to find, as fossils of it must still be buried somewhere. On top of that, you might be a bit dinosaur after all, with your hair being related to their shells.

Click here to read more biology posts.

Sources:

http://advances.sciencemag.org/lens/advances/2/6/e1600708

https://en.wikipedia.org/wiki/Origin_of_birds

https://upload.wikimedia.org/wikipedia/commons/8/84/Bearded_Dragon_-_close-up.jpg

https://en.wikipedia.org/wiki/Origin_of_birds#/media/File:Archaeopteryx_lithographica_(Berlin_specimen).jpg