Precambrian Noonday deposit in Mosaic Canyon, Death Valley

What's the oldest stuff you’ve ever seen, or better still, touched? Have you ever felt awe from contact with something of great antiquity? How old can stuff be? These are questions that have ravaged my mind since childhood.

I've always loved things of antiquity—antique objects, artifacts, fossils, and rocks. "Like." But what's that got to do with astronomy and space? Well, that's where all the oldest stuff originally comes from…but I'll get to that in a moment. First, an anecdote about old stuff.

In search of the oldest stuff, there I was at Badwater, in Death Valley, the lowest point in the continental US (the place where you crane your neck and strain your eyes to make out the words "Sea Level" on the sign waaaay up the cliff). Not far off, to the south, an alluvial fan slouched off into the salt pan, issuing from an unseen but obviously existent canyon in the mountains that make up the east wall of the valley.

I had learned at the visitor center that those mountains (the Black Mountains) are made of some very old rock: Precambrian rock that was originally laid down about 1.7 billion years ago!

So, up the alluvial fan I scramble, turn left, and up the deep, narrow canyon that the alluvium betrayed…

…to the base of a dry waterfall…

…to a wall of raw, exposed rock, the very bones of the Black Mountains…

…and reach out a hand, pressing palm and fingers firmly to the stuff.

Ahh….

1.7 billion years old; that rock I touched had been rock (albeit slowly transforming) for over a third of Earth's existence, and over a tenth the age of the universe itself. I don't know about you, but I find that awesome! And I had my hand right on it!

When we talk about the age of a rock, it is measured from the time the rock solidified ("aggregated"), either with the cooling of molten lava or magma, or the solidification of sediment. Finding really old rocks on Earth is complicated by weather and geologic processes, which continually transform, bury, and "disaggregate" them. Even so, very old rock can be found in certain places, like Greenland, Canada, Australia, and Africa. We're talking about ages between 2.5 and 3.8 billion years, and maybe more. I'd like to get my hand on some of that!

Get away from Earth and its rock-disaggregating processes and you can find some much older stuff. On the Moon, pretty much all of the material you find lying about is at least twice as old as that stuff I put my hand on at the base of the Black Mountains. On the Moon, significant surface activity (volcanism, bombardment by asteroids) ended some 3 billion years ago, and since then the crust has remained more or less unchanged, other than alterations caused by the occasional meteorite impact. The youngest rocks on the Moon are about the same age as most of the Earth's oldest stuff.

We even have a piece of that old stuff at Chabot: a chunk of 3.3 billion year old basalt brought back by Apollo 15 astronauts–and the only things that separate my hand from its speckly gray surface are two panes of glass and some nitrogen gas. Alas!

Get out to an asteroid or a comet and you may very well be setting foot on stuff that's over 4.5 billion years old, unchanged since the formation of our solar system! Within our solar system, that's about as old as stuff gets, but venture beyond it, perhaps to a planetary system that is older than ours, and you'll undoubtedly find older stuff! (This blog post is beginning to ring of George Carlin material.)

But what's the oldest stuff? I can't give you a rock of age beyond a certain point in time, because it took the early universe some time to develop the elements needed to build rocks-as-we-know-them, through nucleosynthesis in the cores of stars. Before that time, the only "stuff" around (at least that we would recognize as stuff; we won't go into dark stuff right now) was hydrogen and helium, which cannot by themselves a rock make.

But that primordial hydrogen and helium, the original building blocks of all material substances, has been around almost from the beginning of time, 13.7 billion years ago, soon after the Big Bang burst forth on the scene (whatever scene that may have been). Hydrogen, found in every water molecule in every glass of water you drink, in vast abundance within the oceans and waterways of the Earth, and through and through your own body, head to toe, is stuff we live and breathe, and is as old as the universe itself!

I don't know about you, but I find that spine-tingling.

Artist concept of AMS-2 mounted on the ISS.

The Alpha Magnetic Spectrometer 2 (AMS-2), like other space-borne observatory satellites, will make its observations outside of Earth's atmosphere, attached to the International Space Station—but unlike "conventional" satellite observatories such as the Hubble Space Telescope, Kepler, and the Solar Dynamics Observatory, AMS-2 will not observe electromagnetic radiation (light), but rather cosmic rays.

Cosmic rays are energetic, electrically charged subatomic particles whizzing through space, originating from various places such as the Sun, distant stars and supernovae, and other high-energy sources from the most distant reaches of the known Universe. Most cosmic rays are simply high-speed protons (hydrogen nuclei) and alpha particles (helium nuclei). Less than 1% of cosmic rays are heavier atomic nuclei, and electrons. All of these particles are things familiar to us on Earth, the main differences being their exotic origins and their extremely high speeds—often approaching the speed of light.

A tiny fraction of cosmic rays are exotic particles indeed: antimatter, in the form of positrons (the positively charged antimatter counterpart of electrons) and anti-protons.

What is AMS-2 looking for? In a nutshell, it's looking for what we cannot see…. Only about 5% of the Universe is composed of "ordinary" matter—the stuff we are made of, and which we can see with telescopes out in the universe by virtue of the light it emits: stars, galaxies, nebulae, giant molecular clouds, and more.

An estimated 95% of the Universe's bulk is made up of "dark" stuff—dark matter (about 20%) and dark energy. Some of this dark matter may be accounted for by massive objects that we can't see, such as black holes, but the primary constituent probably consists of exotic particles that defy direct detection. A number of particles that fit this bill have been theorized, like neutrinos, and more recently neutralinos. In theory, interactions between neutralinos should produce charged particles in the form of cosmic rays that AMS-2 should be able to detect. If it does, then we'll have observational evidence for the existence of this exotic particle, which would shed some light onto some of the Universe's dark mystery….

AMS-2 will also look for antimatter. The Big Bang theory (the theory, not the TV show) of the formation of the Universe suggests that there should be equal parts matter and its counterpart antimatter, but so far we've mostly seen only the former. While there are positrons and anti-protons flying about that can be accounted for by processes involving nuclear interactions, if AMS-2 can detect a more complex anti-particle, like an anti-helium nucleus (an atom composed of two anti-protons, two anti-neutrons, and two positrons), then we'll have an example of antimatter that formed by more complex processes than a random nuclear collision or decay.

AMS-2's "lens" is not made of glass, but of magnetic fields. Conventional telescopes bend and focus light with glass lenses or curved mirrors, but AMS-2 will observe electrically charged cosmic rays, which can be collected and sorted with magnetic force. AMS-2 will count cosmic rays, determine what types of particles they are, and how much energy they possess (how fast they are moving).

From Earth's surface observing cosmic rays is nearly impossible, at best. The particles interact with the nuclei of atoms in our atmosphere, forming a different subatomic particle and a burst of "secondary" cosmic radiation—which can be detected by ground-based instruments, but only as "second hand" news. In fact, it is cosmic ray interactions with ordinary carbon (carbon 12) in Earth's atmosphere that transform them into the radioisotope carbon 14, which scientists take advantage of to determine how long a sample of formerly living material has been dead (as in carbon dating).

So, stay tuned for news on what scientists discover as they peer into the very dark darkness of a currently unknown realm of existence. Should be exciting….

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Magnets in the LHC. Photo copyright CERN

When protons smash together at velocities approaching the speed of light, tiny short-lived particles are produced. If we can see these particles and learn how they behave, we can answer some pretty important physics questions — like what, exactly, is mass? The Exploratorium has a great website that explains physics' Standard Model — what matter is made of, and how the different components of matter interact. In his op-ed piece in the New York Times, Columbia University physicist Brian Greene describes the particles that physicists are looking for: the Higgs boson, the supersymmetric particles, and the transdimensional particles. Is there really a fourth dimension? Or a fifth or sixth? We may soon find out.

The latest nickname for the LHC is "the why machine." That moniker originated on the physics blog Cosmic Variance. Hopefully this feat of engineering will explain why E=mc2. Or, say some, just open up a microscopic black hole that will swallow the entire universe. This is exceedingly unlikely, but, says the Telegraph, some scientists have still received death threats from folks concerned about the impending end of the universe.

These mysterious particles may or may not be linked to the end of the universe, but they were certainly abundant at the beginning, with the Big Bang. To learn more about the Big Bang and the evidence for its occurrence, check out QUEST's interview with Berkeley physicist George Smoot — he won the Nobel Prize for detecting and analyzing the Big Bang's leftover radiation.

Parts of the Large Hadron Collider were designed and constructed by scientists here in the Bay Area. Scientists from the Lawrence Berkeley National Laboratory designed the LHC’s distribution feed boxes, which connect electrical power to the focusing magnets. And scientist from the Stanford Linear Accelerator Center designed the ATLAS pixel detector, which, like a giant digital camera, records what happens after particles collide.

If you're more interested in pictures than particles, then check out National Geographic's photos of the LHC –- it is a beautiful machine.

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