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Moonlight Mini-Lesson

The above photo by Andrew Tallon was taken at 10:30 pm! What I love about this image is it perfectly exemplifies that our moon is just a reflector for sunlight.

So why don’t we see our night landscape this way, if a camera can capture it?

A number of fascinating factors!

Our moon’s albedo (the measurement of amount of light reflected by astronomical objects) is 0.12, which means about 12% of light which hits the moon is reflected. This amount is subject to fluctuation by numerous factors, including the phase of the moon. The amount which hits the earth’s surface can be–and frequently is–significantly less.

To capture the above image, the shutter was open for 30 seconds. Our eyes have our own tricks for seeing in low-light scenarios, which involve our fantastic friends the rods and cones. The outer segment of rods contain the photosensitive chemical rhodopsin (you might know this as visual purple). Cones contain color pigments in their outer segment. Our rods predominantly help us in low light level environments, which means that we have significantly decreased color perception in moonlight.

Cones are located in the center of the eye and are high-density. Rods meanwhile are located around the cones, so in extreme darkness, a 1° blind spot is developed in the central region of the eye where there are only cones. Rods reach their maximum concentration around 17° each direction from the center line, so sneaking some sideways glances actually improves your nighttime perception.

Our rods are not equally sensitive to all wavelengths of light. They are far more sensitive to blue light, and at around 640 nm, are pretty much useless! Click this graph from the University of New Mexico to check it out:

This means that the color of light the moon is actually reflecting appears significantly different to us because of its low intensity.

A neat example I found on the American Optometric Association’s Website which caught my interest was:

For example, in a darkened room, if one looks at two dim lights of equal illumination (one red and one green) that are positioned closely together, the red light will look brighter than the green light when the eyes are fixating centrally. If one looks to the side of the dim lights about 15-20 degrees, the green light will appear brighter than the red.

If you’re planning on shooting your own moonlight landscapes, be a light geek! It is hard to find focus at night, so place a luminous object near your focus, whether it’s a lantern, or a friend with their cell phone! If you want to be super geeky, tape a laser pointer to the top of your camera, then manually focus on the dot.

 

So, with all of this science in mind, how would you replicate moonlight now, vs how you did previously?

A Quasar with 140 Trillion Times the Water in All of Earth’s Oceans.

So, something exciting happened in the world of Astronomy and Astrophysics this last week – two groups of scientists and astronomers at CalTech discovered a mass supply of water in the form of water vapor, living at the center of a quasar called APM 08279+5255, about 12 billion light years away.  That is a lot of water.  That is also a lot of water that just happens to be hanging out in the literal middle of nowhere.

For a little perspective, that water supply is 100,000 times larger than our Sun, and it’s 7.2X10+22 miles away.  There’s about six trillion miles in a light year, and this quasar is about 12 billion light years away.  That’s 72,000,000,000,000,000,000,000 miles away from Earth.  So, this being the case, if we start hitchhiking now, we should make it there by – actually we’ll never make it there.  Not in our lifetimes!  At least not until we invent the Event Horizon, but from what I understand they had a bit of trouble with that ship being all possessed and everything.

Now, something to consider is that these things are way, way old when we actually see the light from them.  That light is at least 12 billion light years old, which means it took 12 billion light years to get to us.  We can measure these things with different kinds of measuring devices that look for the electromagnetic waves that move at faster speeds, like infrared and microwave, that occur “before” the visible light spectrum.  Radio waves and microwaves are very long and infrequent, compared to ultraviolet waves, which are very frequent and short.  Like this:

Okay – first and foremost, what is a quasar, exactly?  Well, honestly we don’t really know all there is to know about them, they’re so far away and of such mass that obviously all we can do is speculate and theorize.  We can observe them with radio telescopes and devices that observe the range of electromagnetic energy between infrared and microwaves (see the Z-Spec gear at the Caltech Submillimeter Observatory in Hawaii and the Combined Array for Research in Millimeter-Wave Astronomy (CARMA)) as well as with very large telescopes like Hubble.  Generally, what is thought to be happening in a quasar is that a large black hole is consuming a whole lot of material in space – between 10 and 1000 sun masses per year, apparently.  That is a whole lot of material that these overweight pigs of black holes turn directly from mass to energy.  So, considering we’re completely skipping a matter form, something has to happen to the material when it’s converted to energy, and that is generally what is referred to as the quasar, or quasi-stellar radio source to the real scientists.  Check out this beautiful artist depiction of a quasar doing its thing (and the image at the top of the post is also an artist’s depiction):

Beautiful.  As the black hole eats all of the mass, electromagnetic energy (which includes visible light) emanates from the quasar.  So, quasars are powered by black holes.  Make sense?  Kinda?  In short, a quasar is a large luminous stellar body.  It’s a monster thing that happens in space, and some of the brightest ones give off more energy than a few trillion of our sun.

Here’s another video, this one explains a bit about Einstein’s Cross and some of the way that the light form quasars is altered by gravitational forces:

Quasars.  Very cool.  Now how do we equate the awesomeness of all that water vapor and the incredulous distance between us and it?

Thanks Count Infinity, Virginia Astrophysics, CalTech AstrophysicsVirginia Tech AstrophysicsUPenn, WiseGeek, and NASA!

The World’s Smallest Incandescent Lamp

planck

The world’s smallest incandescent lamp has been created. And I don’t mean that they’ ve created a little mini table lamp that has a little red shade and a tiny, tiny pull string either.

Scientists at UCLA Physics and Astronomy have created an incandescent lamp with a single carbon nanotube that’s 100 atoms long.  How on EARTH did they get 100 atoms stuck together?  Do you need wee little needle-nose pliers?

<crickets>

But all tomfoolery aside, this little tiny incandescent lamp has some interesting properties.  The little filament inside the lamp is so very small that it allows scientists to study it as both a quantum mechanical molecular model, but large enough in scale that it can still be applied to the laws of thermodynamics.  Do you know what Planck’s Law is?  It’s a measure of the amount of all wavelengths of light that are emitted from a black-body radiator at a given temperature.  Don’t puke:
planck
It’s quantum physics stuff.  Alas, let’s just read the press release, shall we?

In an effort to explore the boundary between thermodynamics and quantum mechanics — two fundamental yet seemingly incompatible theories of physics — a team from the UCLA Department of Physics and Astronomy has created the world’s smallest incandescent lamp.

The team, which is led by Chris Regan, assistant professor of physics and astronomy and a member of the California NanoSystems Institute at UCLA, and includes Yuwei Fan, Scott Singer and Ray Bergstrom, has published the results of their research May 5 in the online edition of the journal Physical Review Letters.

Thermodynamics, the crown jewel of 19th-century physics, concerns systems with many particles. Quantum mechanics, developed in the 20th century, works best when applied to just a few. The UCLA team is using their tiny lamp to study physicist Max Planck’s black-body radiation law, which was derived in 1900 using principles now understood to be native to both theories.

Planck’s law describes radiation from large, hot objects, such as a toaster, the Sun or a light bulb. Some such radiation is of fundamental and current scientific interest; the thermal radiation left over from the Big Bang, for instance, which is called the cosmic microwave background, is described by Planck’s law.

The incandescent lamp utilizes a filament made from a single carbon nanotube that is only 100 atoms wide. To the unaided eye, the filament is completely invisible when the lamp is off, but it appears as tiny point of light when the lamp is turned on. Even with the best optical microscope, it is only just possible to resolve the nanotube’s non-zero length. To image the filament’s true structure, the team uses an electron microscope capable of atomic resolution at the Electron Imaging Center for Nanomachines (EICN) core lab at CNSI.

With less than 20 million atoms, the nanotube filament is both large enough to apply the statistical assumptions of thermodynamics and small enough to be considered as a molecular — that is, quantum mechanical — system.

“Our goal is to understand how Planck’s law gets modified at small length scales,” Regan said. “Because both the topic (black-body radiation) and the size scale (nano) are on the boundary between the two theories, we think this is a very promising system to explore.”

The carbon nanotube makes an ideal filament for this experiment, since it has both the requisite smallness and the extraordinary temperature stability of carbon. While the intensive study of carbon nanotubes only began in 1991, using carbon in a light bulb is not a new idea. Thomas Edison’s original light bulbs used carbon filaments.

The UCLA research team’s light bulb is very similar to Edison’s, except that their filament is 100,000 times narrower and 10,000 times shorter, for a total volume only one one-hundred-trillionth that of Edison’s.

My guess is that we”ll hear about these again.