Monday, 21 November 2016

Pluto got tipped over by its ice cap

Pluto is an extremely cold planet with quite a lot of ice. So much so that New Horizons discovered that it even tilted Pluto to its side.

That’s a whole lot of ice
A few months ago, space probe New Horizons flew past Pluto. The advanced equipment it has on board includes a device that detects solarwinds, an ultraviolet detector, and a multitude of cameras and telescopes. These cameras have already taken extremely detailed pictures of Pluto, revealing things about the dwarf planet that we had no idea about previously. For example, we now know that our previous information about Pluto’s size was inaccurate; it is a bit bigger than we thought, but unfortunately still not big enough to be classified as a planet. New Horizons also discovered that a large part of Pluto is covered by a tear-shaped ice cap which is so big and so heavy that scientists think that it has actually caused the dwarf planet’s tilt.

There goes your frisbee
Pluto’s rotational axis is tilted about 60 degrees. Previously, scientists had no idea what the reason was. Now, James Keane and his team think it has something to do with the enormous ice cap, Sputnik Planitia. They think that the ice cap is so heavy that it has actually tipped over the dwarf planet a little. Imagine Pluto as a frisbee and the ice cap as a small weight stuck to one side of the frisbee. If you throw the frisbee, it will tilt to the side because of the weight; the same thing has happened to Pluto.

The imaginary bar is shown in re

Hey moon!
But there’s something else that’s a bit odd about the icecap that has to do with Pluto’s moon. Pluto and its biggest moon, Charon, are always facing each other with the same side. So a Plutonian would only ever see one side of Charon and a creature living on Charon would only see one side of Pluto. Pluto and Charon seem to be connected to each other by an imaginary bar. The ice cap however, is located exactly opposite to the side that’s facing Charon. So our Charon-creature would never see the icecap. And this is exactly one of the places where a heavy weight like the ice cap could be located without tilting the dwarf planet further. If you imagine the frisbee with the weight again, but now, you stick the weight exactly in the center of the frisbee. Then it won’t tilt to the side anymore when you throw it. The same is true for the location of the ice cap on Pluto, because Charon keeps the dwarf planet in check.

Satellites are expensive
But the problem is, we can only guess how heavy the icecap is. And how it actually influences Pluto’s gravity. To study this more closely, we need a satellite orbiting around Pluto. This satellite could then study closely how Pluto’s gravity field behaves, and if the ice cap actually has any effect on it. This won’t happen anytime soon however, since it’s incredibly difficult and expensive to get a satellite in orbit around such a distant dwarf planet. But for now, it’s a good explanation for Pluto’s tipped axis and the location of Sputnik Planitia.

Click here to read more about astronomy.


Saturday, 12 November 2016

Zombie mice and fish?

When you’re dead, you’re dead, right?  Which means nothing is going on in your body anymore. But recent studies have proven that that may not be so true after all.

It’s alive!
Alexander Pozhitkov and his team have published a study in which they discovered that some genes keep being active for up to a few days after an organism died. Or after mice and zebrafish died, at least, because that are the two species Pozhitkov and his team studied. They found out that the cells in those animals keep producing proteins, because that’s what genes do, up to four days after the zebrafish died. The genes in the mouse survived a little shorter; up to a day. This is really weird, because this essentially means that the cells of the mouse are still alive after the mouse died. From this, Pozhitkov and his team concluded that these cells must also still have enough energy to create these proteins. This is something scientists thought was impossible. Because when an organism, like a mouse, is dead, its heart stops. This means now blood flows through the mouse’s body anymore, and its cells don’t get enough oxygen and can’t produce any energy anymore. But it appears that some energy is still around in the cell.

Nah, not really.
But does this mean that zebrafish and mice are essentially zombies for up to four days? Of course not. All active genes are related to stress, immunity and inflammation. So those genes are only creating proteins that were useful in the few moments before the mouse or zebrafish died. And since a mouse or zebrafish can’t live with only those proteins. Because mice and fish, like all other organisms, also need other proteins to grow, digest their food, move and generally live. And since the mice and fish lack those when they die, they just stay dead. That’s also we don’t see zombie mice or zebrafish in our daily lives, because they need way more proteins to become alive or a zombie.

Better transplantations
But this can help us greatly when it comes to learning more about transplantation. Since mouse-genes live after the mouse died, it is quite likely that human genes do the same. Pozhitkov and his team are thinking about new transplantation methods that can make use of these still-active genes. We could use this knowledge to keep transplantation organs ‘fresh’ for a longer period of time, and we also could learn how to ‘revive’ organs that would otherwise be useless for transplantation. This can be a great advantage for the medical world in general, and especially for the people waiting for an organ transplant.

Click here to read more about biology.


Not only a new president; also new solar panels!

Solar cells will probably be one of the cornerstones of our civilisation in the near future. So scientists are continuously trying to improve the solar cells we have today. Their newest innovation are perovskite solar cells.

That’s way easier!
These new solar cells use inexpensive, commonly available materials. Which means that they are on their way to be used everywhere! On top of that, these new solar cells are just as good, or maybe even better than the solar cells we use today. Their secret is that they’re made of perovskite. Perovskite is a material that is mostly made of calcium-titanium crystals. And it is relatively easy to find calcium and titanium in the earth’s crust. Furthermore, Giles Eperon, Tomas Leijtens and Kevin Bush, the scientists that developed these new solar panels, could build the solar panels quite easily in their laboratorium. Something that is unthinkable with the solar panels we currently use, since they can only be manufactured at extremely high temperatures.
The alternating layers or perovskite
Combining the best traits
But the advantages don’t stop here yet. Perovskite solar panels are also thinner, more flexible, cheaper and better at capturing energy than the solar panels we currently use. Which are made of silicium, or basically just sand. Eperon and his team managed to achieve most of these advantages with just one trick. Instead of just using one layer of perovskite for their solar cell, they used two. And two layers with totally different abilities to be precise. The first layer can only absorb some specific types of light, but can then turn that into a super high electrical energy output. The second layer isn’t that picky and can absorb almost every type of light, but only puts out little electrical energy. By combining those two, the scientists got one super efficient solar cell.

There are some clouds...
But it’s not all sunshine with these new solar cells. Perovskite is known to degrade more quickly than silicon when exposed to moisture or light. But this problem mostly arises when the solar panels contain tin. And scientists have already found a way to work around this. They’ve designed perovskite solar panels that don’t contain any tin at all. So the only thing that the researchers have to do is perfect their design so that the solar panels can generate a maximum amount of electrical energy, and the solar panels are ready to roll.

Click here to read more about physics.