Halos on Mars

By JoEllen McBride, PhD

Curiosity Discovery Suggests Early Mars Environment Suitable for Life Longer Than Previously Thought.

 

We have been searching desperately for evidence of life on Mars since the first Viking lander touched down in 1976. So far we’ve come up empty-handed but a recent finding from the Curiosity rover has refueled scientists’ hopes.

 

NASA’s Curiosity rover is currently puttering along the Martian surface in Gale Crater. Its mission is to determine whether Mars ever had an environment suitable for life. The clays and by-products of reactions between water and sulfuric acid (a.k.a. sulfates) that fill the crater are evidence that it once held a lake that dried up early in the planet’s history. Using its suite of instruments, Curiosity is digging, sifting and burning the soil for clues to whether the wet environment of a young Mars could ever give rise to life.

 

On Tuesday, scientists announced that they discovered evidence that groundwater existed in Gale Crater long after the lake dried up. Curiosity noticed lighter colored rock surrounding fractures in the crater which scientists recognized as a tell-tale sign of groundwater. As water flows underground on Earth, oxygen atoms from the water combine with other minerals found in the rock. The newly-formed molecules are then transported by the flowing water and absorbed by the surrounding rock. This process creates ‘halos’ within the rock that often have different coloration and composition than the original rock.

 

Curiosity used its laser instrument to analyze the composition of the lighter colored rock in Gale Crater and reported that it was full of silicates. This particular region of the crater contains rock that was not present at the same time as the lake and does not contain the minerals necessary to produce silicates. So the only way these silicates could be present is if they were transported there from older rock. Using what they know about groundwater processes on Earth, NASA scientists determined that groundwater must have reacted with silicon present in older rock creating the silicates. These new minerals then flowed to the younger bedrock and seeped in resulting in the halos Curiosity discovered. The time it would take these halos to form provide strong evidence that groundwater persisted in Gale Crater much longer than previously thought.

 

Credit: NASA/JPL-Caltech Image from Curiosity of the lighter colored halos surrounding fractures in Gale Crater.
Credit: NASA/JPL-Caltech Image from Curiosity of the lighter colored halos surrounding fractures in Gale Crater.

This news also comes on the heels of the first discovery of boron by Curiosity on Mars. Boron on Earth is present in dried-up, non-acidic water beds. Finding boron on Mars suggests that the groundwater present in Gale Crater was most likely at a temperature and acidity suitable for microbial life. The combination of the longevity of groundwater and its acceptable acidity greatly increases the window for microbial life to form on young Mars.

 

These two discoveries have not only extended the time-frame for the habitability of early Mars but lead one to wonder where else groundwater was present on the planet. We hopefully won’t have to wait too long to find out. Curiosity is still going strong and NASA has already begun work on a new set of exploratory Martian robots. The next rover mission to Mars is set to launch in 2020 and will be equipped with a drill that will remove core samples of Martian soil. The samples will be stored on the planet for retrieval at a later date. What (or who) will be sent to pick up the samples is still being determined.

 

Although we haven’t found evidence for life on Mars, the hope remains. It appears Mars had the potential for life at the same time in its formation as Earth. We just have to continue looking for organic signatures in the Martian soil or determine what kept life from getting its start on the Red Planet.

 

Space: the Spooky Frontier

 

By Knicole Colon, PhD

Have you ever thought about how spooky space is? Sure, the stars in the night sky are beautiful to look at, and it’s amazing to see the Moon and know that mankind has (literally) left footprints there. But, when you really think about it, you will realize that space is incredibly spooky.

First of all, the Sun is an unfathomably hot ball of gas that randomly emits bursts of radiation (known as flares). Luckily, the Earth’s atmosphere protects us from this radiation. Satellites orbiting above the Earth aren’t so lucky. The radiation from the Sun can affect their operation and effectively cause radio blackouts. Such blackouts can interrupt GPS and other satellites that help us communicate. Considering that we are all addicted to constant communication through our cell phones and the internet, this is pretty scary. On the plus side, such intense flares are really not that common (so try not to get too creeped out by this).

Besides the Sun, there are quite a few asteroids out there that could swing by and impact Earth. This really is a rare occurrence, but it’s still creepy to think of some impact event that is explosive enough to send us back to the stone age. In this day and age, anything that deprives us of technology is pretty scary. And then there are things like black holes or stars that explode and go supernova that could easily destroy the entire Earth. We wouldn’t even stand a chance against them. Luckily astronomers don’t think these will affect us anytime soon (at least not in our lifetime).

There are also some pretty creepy aspects of space travel. In particular, the movie Gravity comes to mind. From the previews of the movie alone, you could see how an astronaut may end up in a really bad situation – floating in space, unconnected from everything, destined to die alone. I definitely like my alone time now and again, but floating into nothingness, waiting to die? Not so fun.

Thinking of the bigger picture and just how vast the universe is, it is quite spooky to think of how small and insignificant each human is in the grand scheme of things. Space is big. Absolutely enormously and insanely big. It takes decades just to travel to the outer edges of the Solar System from Earth, so imagine how long it would take to travel to the nearest star (hint: it would take tens of thousands of years with current technology). Not only that, but what else is out there (besides scary rogue asteroids and black holes)? Are there other intelligent beings, devising a way to attack us? Starting in the late 1800s, people truly believed that Martians existed. People saw “canals” and an infamous “face” on Mars that they thought had been constructed by some intelligent life form. These were actually optical illusions (and people seeing what they wanted to see), but still these observations led to stories like “War of the Worlds” where the main goal of Martians was apparently to destroy humans. We now know that no intelligent life exists on Mars (which is probably good since it means there are no interplanetary wars we have to watch out for). But, what if there is no other intelligent life at all? How scary is it to think we might be alone in the universe?

To end things on a positive note, at least from this post you know you are not alone in thinking that space is a really spooky frontier.