Monday, January 2, 2012


Our Moon

The Earth's size in relation to Mars

The GRAILs attack the Moon

Dr. Marie Zuber of M.I.T.

Planetoid smack down 4.45 billion years ago

The Moon's possible interior

Testing the GRAILs

Looking good

Getting packed

Ready for launch

And away we go!

Planned future missions

Let's talk about our good friend the Moon.
I see it almost every day as I walk over the Sixth Street Bridge in the early mornings. I can't help it. It's way up in the sky and in plain view. It's not trying to hide at all.
Of course everybody except Bill O'Reilly knows how the moon came into existence, but I'll go over the whole scenario again just to refresh our memories.
The whole solar system formed approximately 4,567,000,000 years ago. Our planet, the Earth coalesced about 60 million years later. The solar system was a very messy and inhospitable place at that time. The Earth was a big molten spheroid that rotated much faster than it does today, in 7 hours as a matter of fact. The Sun was only 70% as bright.
Then about 50 million years later, as the molten Earth was strolling around the Sun in it's orbit, minding it's own business, a planetoid about the size of present day Mars, which is a little more than half the size of Earth (picture above), sometimes called Orpheus or Theia, smacked right into us!
How rude!
Anyway, after the two bodies collided a big chunk broke away and eventually formed our Moon. At that time the Moon's orbit around the Earth was much closer, about 40,000 miles away. That's pretty close considering the Moon is now 238,857 miles from us.
Okay, to make a long story short (and I mean really long), after about 50 more million years gravitational tidal locking caused just one side of the smaller body, the Moon, to permanently face the Earth. Our original atmosphere of hydrogen and helium escaped into to outer space because to Earth's mass was and is too small to hold it, which is okay. We didn't need it anyway.
Our Earth's day would lengthen, and the Moon's orbit would increase, or get further away from the Earth. All of this happened in what is called the Hadean Eon.
Our fundamentalist religious friends who believe God created the Earth 10,000 years or so ago can take a small amount of comfort in the fact that there is no direct evidence of anything that supposedly happened during the Hadean Eon. No one was around at the time to record it!
Yet the fossil evidence fairly well dismisses their theory, and the above explanation of the Moon's formation is the only one that doesn't have a major flaw in it according to present day observations and scientific conjecture.
During the next Eon, the Archaean Eon, which took place 3.8 billion to 2.5 billion years ago, the Earth cooled down and it's surface changed from molten to solid rock, water began to condense into liquid form, and about 3.5 billion years ago life began to emerge in that water. Life that produced oxygen, which is badly needed for most life forms today. The Sun brightened, the Moon continued to drift away from the Earth and started working it's magic on the our ocean's tides, our day became longer, and a planetary magnetic field began to form. At approximately 3 billion years ago our atmosphere consisted of 75% nitrogen and 15% carbon dioxide with oxygen levels continuing to rise due to the emergence of life. Today our atmosphere consists roughly (by volume) 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.039% carbon dioxide, and small amounts of other gases. It also contains a variable amount of water vapor, on average around 1%. This means that every time you and I, or practically anybody else you may know takes a breath, they're sucking in a huge amount of nitrogen... which is kind of creepy when you think about it... so I don't. Sorry I brought it up.
This is all fascinating and all, but really has nothing to do with what this post is about so let's get on with it, shall we?
Last year, on September 10th to be precise, two spacecraft, GRAIL A, and GRAIL B, identical craft, were launched into space on the same rocket, their final destination... our Moon.
You may be wondering what the hell does GRAIL stand for. I know I certainly did, and I found out! It stands for Gravity Recovery And Interior Laboratory. Isn't that wonderful!
It took America's Apollo astronauts only about 3 days to traverse those 238,857 miles to the Moon. The two GRAIL spacecraft took their sweet time so that NASA engineers could fully power them up before they arrived and play with them. When they got tired of playing with them they allowed them to insert themselves into the Moon's orbit. As a matter of fact GRAIL A fired it's insertion burn December 30th at 1:21PM my time, which is the only time that matters. It was still about 30,758 miles away from the Moon at that time. GRAIL B did the same thing yesterday at 2:05PM. Actually, I hope it will, because as I write this it hasn't done so yet, but is supposed to in about 45 minutes.
Anyway, these two craft are destined to achieve a polar orbit around the Moon, slowly positioning themselves on exact opposite sides of our nearest neighbor. They'll both be traveling at about 428 miles per hour, and once the final positioning burns have been completed they will be at an altitude of 34 miles above the Moon's surface, in a near circular polar orbit (orbiting above the Moon's North and South Poles), each completely circling the Moon every two hours. It will take until March of this year to get these guys in place just right.
Once they get in position GRAIL A & B will enter their science phase, which is why they're there to begin with. I bet you were wondering why they were going there. Well I'll tell you. They are going to measure the Moon's gravitational field as the moon rotates beneath them. You see as the two satellites orbit above the Moon's surface, the Moon's gravitational field will act on them in very minuscule ways, pushing or pulling them away or toward each other which the crafts will measure in some detail. They're very good at that, as that is what they were designed to do. They'll do this until May, at a cost of $496 million U.S., none of that Hong Kong stuff.
The purpose of these measurements is to learn what lies below the Moon's surface. It's like they're giving the Moon a big CAT scan. The Apollo astronauts brought back to Earth about 800 pounds of Moon rock, but that didn't tell us anything about what was going on below the surface, if anything. There probably isn't anything going on below the surface as the Moon is most likely dead geologically speaking, but we want to know what's down there anyway as this information will help us learn more about how the Moon, Earth and other terrestrial planets, like Mars, Venus, and Mercury formed. And it will of course allow us to eventually discover the Tycho Monolith Magnetic Anomaly featured in "2001, a Space Odyssey."
The lovely Dr. Maria Zuber, the E. A. Griswold Professor of Geophysics at the Massachusetts Institute of Technology, who also leads the Department of Earth, Atmospheric, and Planetary Sciences, is in charge of the GRAIL mission, or as in charge as one can be of two satellites a quarter of a million miles away. She says she hopes to find out a whole bunch of stuff from this mission. That's a scientific term... "whole bunch of stuff," or WBS for short. For instance there is a recent theory that postulates that there was once two moons orbiting around the Earth, each moving rather slowly in relation to each other. At some point the theory goes, the smaller moon nudged into the larger due to gravity, and the two eventually coalesced into one entity. Dr. Zuber thinks the lunar highlands situated on the side of the Moon facing away from the Earth may be the point where the two came together, and that the GRAIL mission may help to prove or disprove this theory. We shall see.
This one experiment is the only thing these two satellites were designed to do... except for this other thing. And it's a really good thing! For kids!
Aboard each craft is four cameras to take pictures of the lunar surface. Not for scientists. They already know what the Moon looks like. No, it's for school kids and their teachers to use. They can go to the "Moonkam" website, where they can find out the exact locations the GRAIL probes will be flying over. They can then pick a site and request that it be photographed. Isn't that wonderful too! I certainly couldn't do that when I was in Jr. High School. I could hardly do anything when I was in Jr. High School.
This is the first time ever that NASA has included this type of feature on a scientific mission specifically for educational purposes. Good for them! And good for the American tax payers who paid for it! All of us here at Joyce's Take salute you.
America's first female astronaut, Sally Ride, will be helping out with this part of the program. Leesa Hubbard, a teacher at Sally Ride Science, says “I think once they [the kids] begin to look at detailed images, when they go out in their backyard and look at the moon, they’re gonna look at it in a whole new way and I think that’s priceless.”
I couldn't agree more!
All students from around the world can do this due to the Internet machine. All they have to do is register a picture request, after which the process can be followed. From when the commands are sent to GRAIL, when they take the picture, and then when it's downloaded to the website photo gallery.
After the GRAIL science mission is completed both satellites will crash into the lunar surface in about 40 days and would have gone "BOOM" if there were an atmosphere available to transmit the sound.
One of the two good things that George W. Bush did as President was to initiate the Vision for Space Exploration program which called for a manned return to the Moon by 2020 (the other was the establishment of the Papahānaumokuākea Marine National Monument in Northwestern Hawaii). When Presidents put into place these long period projects they know that the next President can do anything they want, like replace the program. That's exactly what President Obama did when he gained office and initiated his U.S. National Space Policy, which canceled the proposed Moon trip, among other things. He did this as a cost cutting move which was basically politically motivated. He was wrong to do this.
Now China and Canada have announced ambitious plans to land astronauts on the Moon within this decade, leaving the USA in the dust. We can't even send very much up into space these days, like people, after the retirement of the Shuttle program. We now have to rely on the Russkies to do that, and you know how temperamental they can be.
There are a lot of reasons for men... and women, to return to space, especially other planets like Mars, and the Moon, though it is not technically a planet. America should be a leader in this exciting endeavor. We need to care less for short term political gain by restricting the budgets of our national space program, stop funding unnecessary wars and wasting money by giving it to the defense contractors and oil companies, and get our act together and head on out there. Our survival as a species may one day depend on it.
Still missions like GRAIL, and other robotic experiments to Mars and the asteroids, are an important step for the advancement of scientific knowledge generally, and for humanity as a whole, and should be looked at as a stepping stone for us to explore, and colonize, the rest of our solar system.
It's waiting for us to come say hello.

No comments:

Post a Comment