Another matter

Aurora Borealis; the Northern Lights.
Aurora Borealis

When is a substance not a liquid, solid, or gas? Give up? When it’s plasma, the fourth state of matter. (Not blood plasma, which is something different.)  Alas, my elementary school science failed me. And now…literally, decades later, I have become re-enchanted with this fact.

So, for those of us who are a bit out of touch with plasma, I’ll paraphrase a bit about this state. To begin with, what exactly is plasma?

Plasma is a super-heated gas that becomes so hot its electrons leave the atom’s orbit and roam free. A gas becomes a plasma when extreme heat causes its atoms to shed their electrons.

Okay, that’s cool, but where is it? We recognize the other states of matter, but what about this mysterious thing? Plasma is the most abundant form of visible matter in the universe and believed to compose up to 99 percent of what we see in the night sky; populating the infinite regions of interstellar and interplanetary space. Like the sun, stars are enormous balls of plasma. The fusion fueled by plasma creates the energy that gives us sunlight, which as we know, is essential for life on Earth.

Hmmm, so if this plasma is another state of matter, where else is it found?  Lightning, neon signs, fluorescent light bulbs, a candle flame, some television and computer displays are all examples of plasma. Like a gas, plasma has no shape or a definite volume unless it is enclosed in a container. However, distinctive from gas, when under the influence of a magnetic field, it may form structures such as filaments, beams and double layers.

Can we see it? Aurora Borealis, also known as the Northern Lights, is nature’s way of showing it to us. This occurs because plasma particles hurled from the sun interact with Earth’s magnetosphere, (the magnetic field that surrounds us).

Today’s esteemed thinker is English chemist and physicist, Sir William Crookes (1832-1919). He discovered the element thallium and invented the radiometer, the spinthariscope (a device for studying alpha particles), and the Crookes tube. Not a household name, Crookes discovered the electron when he was reconstructing the Cathode Ray. By placing black vanes on one side and silver on the other, it caused the vacuum tube to spin when it hit the light. Since the Cathode Ray had previously been built, he needed to call it something else. Today it is known as the Crookes’ Tube.

In 1879, while playing with an experimental electrical discharge tube (in which air is ionized by the introduction of a high voltage through a coil), he discovered “Plasma”.  Originally Sir William Crookes called it radiant matter. However, in 1928 Irving Langmuir, an American chemist and physicist, renamed it because he was reminded of blood plasma… go figure! 

Esteemed thinker: Edwin Hubble

hubble-space

The idea that the universe is infinite is a term that defies logic. Humans are a species that likes to feel that beliefs and ideas can be packaged with a beginning and an end. So when it comes to comprehending beyond our visual scope of our universe, we have a difficult time comprehending that there is a forever expanding cosmos. The notion of “endless” is mind-boggling.  NASA’s Hubble Space Telescope, launched on April 24, 1990, on the space shuttle Discovery from Kennedy Space Center in Florida has given us its shared view from a space. It can see astronomical objects with an angular size of 0.05 arc seconds, which is like seeing a pair of fireflies in Tokyo from your home in Maryland. Hubble has peered back into the very distant past, to locations more than 13.4 billion light years from Earth.

And so, having passed its 25th anniversary, there are some who may not know its namesake. Today’s post brings you the esteemed thinker: Edwin Hubble (1889-1953), American mathematician and astronomer,  born in Marshfield, Missouri.  Having received his first telescope at the early age of eight, his passion for astronomy was established quite early.

Although his father wanted him to pursue different interests, Hubble studied astronomy,  physics, and law; after which he traveled to Britain as a Rhodes Scholar. On his return to the United States, he set out to teach high school and coach basketball, but, he soon switched gears and continued to pursue astronomy studies. In 1915, he earned time on one of the Yerkes Observatory telescopes, launching his new career.

He began his PhD in astronomy in 1914, but postponed his work in 1917 to enlist, serving in France during World War I.  After the war, Hubble was fortunate to be at Mount Wilson, the center of observational work underpinning the new astrophysics, later called cosmology, and the 100-inch Hooker Telescope, then the most powerful on Earth that had just been completed and installed.

He began to classify all the known nebulae and to measure their velocities from the spectra of their emitted light. In 1929 he made another startling find – all galaxies seemed to be receding from us with velocities that increased in proportion to their distance from us – a relationship now known as Hubble’s Law. This discovery was a Edwin hubblesensational  breakthrough for the astronomy of that time as it overturned the conventional view of a static Universe and showed that the Universe itself was expanding.

Hubble worked at Mount Wilson until 1942, when he left to serve in World War II. He was awarded the Medal of Merit in 1946. Returning to his Observatory, his last great contribution to astronomy was a central role in the design and construction of the Hale 200-inch Telescope on Palomar Mountain. Notes as being four times as powerful as the Hooker, the Hale would be the largest telescope on Earth for decades.

Although wishing to win a Nobel Prize, all the effort was in vain since there was no category for astronomy.

From The Realm of the Nebulae (1936), I bring you the words of the great Edwin Hubble, a man with dreams that gave us the universe. “With increasing distance, our knowledge fades, and fades rapidly. Eventually, we reach the dim boundary—the utmost limits of our telescopes. There, we measure shadows, and we search among ghostly errors of measurement for landmarks that are scarcely more substantial. The search will continue. Not until the empirical resources are exhausted, need we pass on to the dreamy realms of speculation…”

First image taken from the Hubble Telescope.