Few planets in our solar system have inspired generations of scientists and children than the planet Mars.  When you think of little green men or aliens, you probably think of the planet Mars versus any other planet.  And there's reason for that.  Mars, more so than any other planet, when you look at it through a small telescope, you can actually see details on the surface of the planet.  The reason for that is because, Earth is orbiting the Sun, Mars is orbiting the sun.  And there's a time a little over once a year, where Mars and Earth are both near each other on the same side of the sun.  And when that happens, Mars is relatively big in the sky and we can see it through a telescope, even a smallish telescope. 


When you look at Mars through a smaller telescope, you can see actually lots of details.  You can see it has little ice caps on the north and south pole.  You can see it has kind of dark lines around the planet, dark areas, and you can even notice with just drawings, astronomers noticed, that there are changes in these things over the course of a year, and from year to year.  And actually, that got astronomers excited because Earth experiences changes like this. We get seasons, we get meltings and thaw where new plants grow.  And that's what astronomers thought, some astronomers thought, was happening on Mars, that as these dark areas would grow and shrink on the surface of the planet, they thought maybe that was vegetation that was spreading; plants that were spreading for the summer and then dying off in the winter.  They could see changes in the ice caps, suggesting when it got warmer and colder.  


And one astronomer in particular even thought he saw another kind of change taking place on the surface of Mars.  In the late 1800s - so picture this, this is just before photography was invented, we had many big telescopes, not the biggest like we have now, but like that really long one.  That's the kind of telescope we have.  And the astronomer, Percival Lowell, was studying Mars.  And when he would study Mars and take pictures, sorry, and draw pictures, this is what he believed he was seeing in these dark regions.  He saw lines, thin lines between these dark regions.  And he became convinced that these dark lines were actually canals that had been dug through the surface of Mars, maybe to transport water to particular cities on the surface of Mars.  So he thought these darker regions were maybe lakes or oceans, he thought these lines were connected to the ice caps, and first of all, Lowell was a relatively well known astronomer.  He was using one of the best telescopes in the US at the time, and so when he suggested this, it was taken relatively seriously and even published in magazines like the Wall Street Journal, where, people thought, wow, there must be Martians, creatures, intelligent creatures living on the planet Mars.  


And for many years and decades, it didn't take long before other astronomers were like, I don't see these features. Are you sure they would with their telescope, they couldn't see the same things, which points to one of the benefits of science.  And that is that people have to repeat the results.  If I do an experiment, and I see something amazing happen, like let's say I mix these, you know, water and flour together, and it explodes, and I tell everybody about it, hey, if you just mix water and flour together, it will explode, well, other scientists are going to try it.  And if it doesn't work for them, they're going to let everybody know; hey, it didn't work for me; right?  So it has to hold up to this idea of peer review that other people have to try it and confirm it.  And that's something that for Percival Lowell never really happened.  No one else saw it and said yes, this actually is what Mars looks like.  But nonetheless, it got people excited about the possibility that Mars of all the planets, maybe that's the one where people like us, creatures like us are living and building cities and things like that.  And that lingers today, in some ways.  If you were to ask people which planet is most like the earth, I bet you a lot of people would say Mars, but actually Mars is much smaller than the Earth. 


The second picture in our gallery shows Earth and Mars and the same scale.  You remember, Earth and Venus are almost exactly the same size, they both have big atmospheres, but Mars is about a third of the size of the Earth.  So if you were walking around on the surface of Mars, you would be a third lighter, and it would be hard to run like, and if you jumped, you could jump much higher, because gravity would be less there, you would weigh less, because the planet is so much smaller. 


And there are other differences between Mars and Earth.  For example, Mars has basically no oxygen in its atmosphere, no oxygen to breathe.  It has a very thin atmosphere and it changes with the seasons, but it's very thin.  Something like if you were three times the height of Mount Everest, that's about how much air there is on Venus on Mars.  And you know that if a mountain climber is on the top of Mount Everest, they have to carry their own oxygen mask because there's so little air there.  Imagine going three times higher up, and that's how little air there is on Mars. 


But there are other really important differences like Mars, because the atmosphere is so thin, there's no liquid water on the surface of Mars.  If you were to pour a cup of water onto Mars, it would very quickly evaporate, because water just can't stay in that kind of environment.  So there's no oceans, there's no rivers, nothing like that.  But even though Mars is so different from the earth, there's evidence as we study the surface up close, that Mars has had a very interesting history; a history that has included water in some in some interesting ways. 


Because Mars is relatively close, and because it has such an interesting surface that we can study, we have unprecedented amounts of data from the surface of Mars.  So not only from the surface, but from spacecraft that we've sent to orbit Mars.  So since the 90s or so, we have had continuously spacecraft orbiting Mars taking pictures of the surface.  And this is one of my favorite pictures, it's of a crater, and what you can see - on Mars - and you can see that at the bottom of the crater is what looks like ripples of sand.  And for me, when I look at this, this reminds me of the pattern of sand that I see underneath water like in the lake near my house near my home.  The sand by waves kind of gets rippley.  But it's just one small example of how sand dunes, a familiar pattern that we see on Earth, also forms on Mars.   So a lot of the geological features you know, craters and canyons, riverbeds, islands, landslides, things that we're used to seeing on Earth we also see happening on Mars. 


One of the newest spacecraft that is the most recent one to be orbiting Mars is called the Mars Reconnaissance Orbiter.  And this spacecraft is taking the most unbelievable pictures, like truly astounding.  It can capture pictures of a tornado happening.  Like on the surface of Mars, there's pictures of these little tornadoes.  It has captured pictures of landslides while they're happening.  The dust is being, you know, thrown into the air and a slant, the sand is sliding down a canyon wall, and they'll capture a picture of that as it happens.  So there are just hundreds of thousands of these amazing pictures.  But one of my favorite pictures that the Mars Reconnaissance Orbiter has ever taken is the fourth picture in our gallery. It's this astounding picture on the left hand side, what is that you think?


It is another spacecraft that was sent to Mars and has a parachute as it's coming down towards the surface, and it's zoomed in on the right hand side.  So we have here one of our spacecraft taking a picture of another spacecraft as its landing.  That's how high quality these missions are now that are orbiting these planets and studying the surface in great detail.  This particular mission that's parachuting down is one of, it's the most recent Rover, that is, you know, a little robot that lands on the surface, and drives all around, and this most recent mission is a Curiosity Rover.  It landed just a few years ago.  It’s about the size of a truck. 


And here's a real picture. The last picture in our gallery is a real photograph that was stitched together that this rover took of itself on the surface of the planet.  And this large rover, about the size of a truck, is like a mobile chemistry lab.  It drives around the surface and it identifies rocks and soil, and it can study the chemistry of those rocks and soil to try to identify whatever it can about what it's made out of, what its history was like, things like that.  Now, why are we doing this?  Why are we studying the surface of Mars in such great detail?  


Well, one of the major questions that we're trying to answer about the surface of Mars is whether there has ever been water on the surface of Mars.  Now, why do we care if there's ever been water?  Well, it gets back to this question of life.  Our understanding of life here on Earth is that it absolutely has to have water in order for life to flourish.  I mean, we need water, obviously; trees need water, basically; all creatures need water in some sort of way.  And so the thought is, if there has ever been water on Mars, then maybe at some point in the past, there used to be life on Mars.  That's the operating question that people are trying to figure out. 


The best evidence from these rovers and from the satellites is that, yes, there has been water, in fact, potentially a lot of water on the surface of Mars in the past.  How do we know that?  Well, we see stream beds that flow, that look like there's flow on the surface, you know, you might maybe have seen dried up streams on the Earth.  Well, we see the same kinds of things on Mars.  But more than that, in these chemical analyses, you see certain kinds of minerals and rocks that can only form in water.  


So one example are these little spheres of iron are like iron balls, these like little, they're called concretions, that form inside rocks, inside sandstone.  And the way they form is that water passes through the sandstone, the iron kind of dissolves into the water and then as the water evaporates, or whatever the liquid is evaporates, then this iron forms in these hard little spheres.  And those have been seen, and other types of minerals have been seen that only form in a liquid environment.  So the evidence appears to be mounting that Mars used to be much warmer and much wetter than it currently is. 


Now, that said, there really is no clear evidence though of any former life that ever existed on the surface of Mars.  Just because there once was water doesn't necessarily mean there once was life.  And finding evidence of life would mean finding things like fossils of creatures that used to live on Mars.  I mean, that would be a pretty amazing piece of evidence that, wow, you know, it looks like something used to live here.  But we don't see any evidence of anything like that.  It's not to say it's impossible. And you know, I wrestle with this as a Christian is, scripture doesn't say anything about life elsewhere in the universe.  It gives a clear impression that we, as humans, have been made in God's image and that we are special in creation.  But it doesn't necessarily say that there couldn't be other animal like creatures and other places in the solar system or in the universe.  It certainly doesn't say that there couldn't be grass on other planets.  And so I wrestle with those questions because there's a piece of me that feels like no, there must not be life anywhere else in the universe because God made life here. 


But you know, I’m surprised to learn that throughout the history of Christianity, some Christians have thought of course the universe must be full of life.  I mean, God is all powerful and creative. He must have created many different places like the earth that are just overflowing with beautiful, amazing creatures we could never even dream of because that's God's creativity at work.  And I suppose that's possible, but it's still, it's something that is a challenging question that we should face because this question of searching for and discovering life elsewhere in the universe is one that's going to continue for the next several decades as astronomers continue to find other planets around other stars and as they continue to try to study those planets to see what evidence there may be for water or for life. 


The one thing we absolutely can agree on though is that this life that has arisen is not the product of just random chance.  We know that life has been designed by our Creator and that's where the narrative that the scientific community puts out versus our story, that's where they don't mesh.  The notion that life arises anywhere there happens to be water and organic, that it's inevitable just by random chance, just doesn't match with what we know to be true both from scriptures and what we know about God through His created world. 


Okay, so Mars, very cool.  And next we'll be turning our attention towards the outer solar system, and the very unusual planets that we find out there.   


Alright, we'll see you next time.



Última modificación: lunes, 25 de septiembre de 2023, 08:45