Posted on 08/23/2006 10:24:06 AM PDT by Boxen
The mystery of how Earth got its Moon is one step closer to being solved.
The European Space Agency's lunar-orbiting craft called SMART-1 has completed the first detailed chemical mapping of the lunar surface. The detected chemicals, such as calcium and magnesium, give a boost to the longstanding theory that the Moon formed from the debris flung into space after a collision between early Earth and a Mars-size planet.
Calcium, in particular, is found deep inside Earth. So if the Moon has a lot of calcium, then perhaps it is made of material that was once inside our planet.
Armed with miniaturized instruments—including an ultra-compact electronic camera, an X-ray telescope the size of a toaster for mapping chemical composition, and high-tech communication gadgets—SMART-1 had lofty goals. It was to pin down out how the Moon came to exist, search for water locked up as ice in the depths of Sun-deprived craters, and map the mineral composition of the Moon's crust.
Apollo science
Prior to the Apollo missions, there was no consensus among planetary scientists regarding the Moon's formation. One theory claimed that the Earth and the Moon formed at the same time from the same disk of swirling dust and gas, while another purported that the Moon is a scoop of Earth that split off in the early stages of our solar system.
Besides sending home awe-inspiring photos, the Apollo missions delivered 842 pounds (382 kilograms) of lunar rocks and soil—the first pieces of chemical evidence to help explain the Moon's formation.
The favored theory now describes a violent collision between the Earth and a planet-size object, which hurled molten rocks and dust from both contenders into space. Over time, the debris congealed into the Moon.
With most Moon know-how coming from Apollo’s six landing sites, scientists saw lots of room for error. To solve the lunar-forming puzzle, a global investigation of the entire surface was needed.
Smart science
Enter SMART-1 (Small Missions for Advanced Research and Technology), a spacecraft equipped with seven high-tech instruments that would give a detailed map of both chemical make-up and topography over the Moon’s entire surface.
One of the most important devices, D-CIXS (pronounced dee-kicks) recorded hours of X-ray data. When the Sun’s rays hit the Moon, the X-rays caused atoms to fluoresce and emit their own X-rays. The D-CIXS (Demonstration Compact Imaging X-ray Spectrometer) telescope translated the amount of energy released into the type and abundance of different elements.
D-CIXS detected the major components of rocks: aluminum, silicon, magnesium, and calcium. However, elements like calcium are not homogenously mixed throughout the Moon. To paint a three-dimensional picture of the chemical composition, planetary scientists needed both surface and “bulk” data.
Cosmic Coincidence
What the project team is calling a cosmic coincidence helped to land that information. On January 2005, a massive solar flare flooded the Moon with X-rays. Meanwhile, the craft was peering over a region called Mare Crisium—the same location in which Russian Landers had collected soil samples in the 1970s. There, the spectrometer detected calcium in similar amounts to the data collected by the landers.
Plus, calcium showed up in broad areas across the entire lunar surface. This rock-building element lends support to the impact theory.
"From SMART-1 observations of previous landing sites we can compare orbital observations to the ground truth and expand from the local to global views of the Moon," says Bernard Foing, Project Scientist for SMART-1.
More work remains to sort out just how significant the calcium findings are.
"We have good maps of iron across the lunar surface. Now we can look forward to making maps of the other elements," said Manuel Grande of the University of Wales and D-CIXS' Principal Investigator.
The findings will be detailed in the Planetary and Space Science journal.
Dark side
Since the Moon’s rotation around its axis is equal to its orbital period, or the time it takes the Moon to travel around Earth, the same side always faces Earth. While scientists have studied samples from the Moon’s near side, the far side and its polar regions have remained in the dark.
For instance, the lunar south pole sits in the solar system’s largest crater, called the South Pole-Aitken Basin, which is 1,616 miles (2,600 kilometers) across and 7.5 miles (12 kilometers) deep. SMART-1 snapped loads of photos of the crater, while gathering chemical data. With such depths, the scientists hope to get a peek at the Moon’s mantle layer, just beneath the crust. Since the Moon accreted material over time, the deeper you go the further back in time you go.
This September, the craft’s nearly three-year mission will come to an end with a fiery crash.
As the craft nears shut-eye, its instruments will keep all eyes on the Lake of Excellence, a volcanic plain area surrounded by highlands in the mid-southern latitudes. Such close capture should give scientists insights into the formation of this region.
I don't think so. The Theory of Relativity is not wrong even if it is misunderstood and misapplied.
Define "super-religious"
Those with a doxographical outlook have adjusted centuries ago to not only other planets but human life on other planets--many other planets. Net doxological revision--zero.
Denser metals sink to the center. When enough Uranium accumulates, well....
That is probably him. Challenging dogma. Somebody ought to.
He has a PhD in astronomy and can hold his own among professional astronomers. I don't know if he is a nut, but has done excellent professional work. Retired now and able to reflect on science and push the knowledge envelope. There are loose ends everywhere in astronomy and he is pointing them out. I won't write him off. Whether others choose to ignore him is their own business.
Uh, no offense, but if your physics knowledge is at the level that you would claim this, I don't think I want to be taking your opinion on the matter very seriously.
And I don't know what the public schools are teaching these days, but NASA says:
This morning at perihelion both hemispheres were 147.5 million km from the Sun. That barely differs from the greatest distance, 152.6 million km in July, which astronomers call aphelion.
I figure that at about three percent variation from perihelion to aphelion. That's close enough to call near-circular in my book.
both will eventually stop rotating.
I keep waiting for Jimmy Carter to stop rotating
but he never does!
' The reason the Moon's rotation equals its period is something called tidal lock. Eventually (in about 50 billion years) the Earth would keep the same face to the Moon as well. However, solar physics dictates that the Sun will consume both prior to this event'
That's good news.
ah, no. that's just captured rotation. not at all uncommon in the solar system.
ah, you got it already. good.
1. you have no idea what you are talking about
2. you have no idea who you are talking to
It would be wiser to be more polite when being given a free education by one who knows far more than you on a given subject.
As to Newtonian Mechanics as apply to inertia, you give only a partial definition, which may explain your error. The Law runs in full: "An object at rest shall remain at rest, and an object in motion will remain in motion with unaltered vector, unless acted upon by an outside force."
The tidal effect of gravitation in a binary system is an outside force.
Did your respond to the wrong post, or do you need to take time to actually read? When did I say anything about which plane to identify as 0-0?
That makes sense. But aligning up with the same face does not. I think most agree that the moon is facing the earth because it split from the earth.
Never mind.
No, they don't.
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