Happy Selfie, Curiosity!


The iconic robot has joined the trend and taking this peculiar image of itself to celebrate his first Martian year in the red planet. He arrived there the 5th of August of 2012, but since a year in Mars takes longer to happen than in Earth, only now has Curiosity reached this milestone. It has been plenty of time for the machine to surprise scientists everywhere with its discoveries, which we will recount in its honour.

Curiosity Selfie

The acclaimed robot takes the first selfie on Mars

On the 27th of September, it was announced the Rover had discovered an ancient riverbed. Of course, there was no water in it, so how did they know it was a river bed? This conclusion was reached because the robot found small, rounded boulders, instead of the sharp ones with jagged edges that usually occur, and the most common explanation for rocks being smooth and curved is due to flowing water transporting them for long distances and eroding them. However, doubt lies as to whether it was actually water flowing, and not some other liquid or maybe even a gas like CO2, but since there are hydrated minerals in Mars, it is most likely water was the liquid. But even if it was an actual river, it doesn’t immediately mean life on Mars exited, because there were no traces of carbon in the area so it is impossible to say if there had actually been living organisms in the area.

September was a busy month, since at that time Curiosity also shone more light into the methane mystery in Mars. In past studies, some scientists had concluded there was a high abundance of methane in Mars, and since methane is mostly produced by living beings, such as cows and rice, some though this was proof of the existence of extraterrestrial life on Mars. But after 8 months of analysing the atmosphere, the rover concluded there was little to none methane there. In fact, it estimated there was only 1 part per billion of methane in Mars. However, it is arguable that some methane is trapped in the planet, so Curiosity will be doing more detailed investigations in the future.

Those are the main ventures pursued by Curiosity, and it has plenty of time to investigate further, since the original 2-year-mission was prolonged indefinitely. For now, please join me on wishing the rover a late Happy Birthday!

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(By the way, this is my 50th post in Science for Scientists after 2 and a half years of blogging. It was about time, right?)

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The Heroine of Tanning


It’s summer: the time for ice cream, spending the day in the beach, and therefore, sun bathing. But apparently this relaxing activity is not as simple as you may think.

When people are exposed to ultra violet radiation, like that coming from the sun, it causes melanocyte cells in the skin to produce melanin, a pigment which absorbs radiation to protect the skin. So when people sun bathe, they produce more melanin which darkens their skin. It also increases Vitamin D production, but can lead to skin cancer and faster ageing skin.

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An endorphin, a substance which gives pleasure, and can be released due to exercise, food and now sunlight!

Up until know, doctors had tried to raise awareness of the dangers of this practice, but it seems things are getting worse. A new study published in ‘Cell’ suggests that constant and prolonged exposure to UV light can be addictive. This theory had already been proposed, with some known cases, but it has now been explained and backed up with an experiment on mice. These were shaved to expose their skin and were then subjected to UV light exposure for a controlled period of time a day, similar to the amount a human would get when sun bathing on the beach. After weeks of this practice, it turned out the mice had produced more beta-endorphin, a substance similar to morphine and heroine, which results in a positive feeling when detected by the sensors in the brain. The pleasant nature of this is what makes the mice crave it more, causing an addictive response, where the mice seek out the stimulus that is causing the endorphins to be released.

It was also found out that the mice showed tolerance to the UV radiation, just as an addicted person does to a drug after using it for a while. Scientists found that over time, they needed to increase the amount of UV light they shone for the mice to produce as much endorphins as before.

It is definitely an interesting study, which adds up to the dangers of being exposed to too much sunlight. That’s why we should be careful with the light exposure we go through everyday, taking care of using sunscreens and trying to reduce as much as possible the time we spend directly under the sun.