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PHVSICS OF THE IMPOSSIBLE
tronomers noticed a strange marking on Mars that looked like a gigantic M that was hundreds of miles across. Commentators noted that perhaps the M stood for "Mars," and Martians were peacefully signaling
their presence to earthlings, like cheerleaders spelling out their team's
name in a football stadium. (Others noted darkly that the M marking
was actually a W, and W stands for "war." In other words, the Martians
were actually declaring war on the Earth!) The mini-panic eventually
subsided when this mysterious M disappeared just as abruptly as it
had appeared. In all likelihood this marking was caused by a dust
storm that covered the entire planet, except for the tops of four large
volcanoes. The tops of these volcanoes roughly took on the shape of an
M or a W.
THE SCIENTIFIC SEARCH FOR LIFE
Serious scientists studying the possibility of extraterrestrial life state
that it is impossible to say anything definitive about such life, assuming that it exists. Nonetheless, we can make some general arguments
on the nature of alien life based on what we know of physics, chemistry, and biology.
First, scientists believe that liquid water will be the key factor in
creating life in the universe. "Follow the water" is the mantra recited
by astronomers as they search for evidence of life in space. Liquid water, unlike most liquids, is a "universal solvent" that can dissolve an astonishing variety of chemicals. It is an ideal mixing bowl to create
increasingly complex molecules. Water is also a simple molecule that
is found throughout the universe, while other solvents are quite rare.
Second, we know that carbon is a likely component in creating life
because it has four bonds and hence the ability to bind to four other
atoms and create molecules of incredible complexity. In particular, it
is easy to form long carbon chains, which become the basis for hydrocarbon and organic chemistry. Other elements with four bonds do not
have such a rich chemistry.
PHVSICS OF THE IMPOSSIBLE
tronomers noticed a strange marking on Mars that looked like a gigantic M that was hundreds of miles across. Commentators noted that perhaps the M stood for "Mars," and Martians were peacefully signaling
their presence to earthlings, like cheerleaders spelling out their team's
name in a football stadium. (Others noted darkly that the M marking
was actually a W, and W stands for "war." In other words, the Martians
were actually declaring war on the Earth!) The mini-panic eventually
subsided when this mysterious M disappeared just as abruptly as it
had appeared. In all likelihood this marking was caused by a dust
storm that covered the entire planet, except for the tops of four large
volcanoes. The tops of these volcanoes roughly took on the shape of an
M or a W.
THE SCIENTIFIC SEARCH FOR LIFE
Serious scientists studying the possibility of extraterrestrial life state
that it is impossible to say anything definitive about such life, assuming that it exists. Nonetheless, we can make some general arguments
on the nature of alien life based on what we know of physics, chemistry, and biology.
First, scientists believe that liquid water will be the key factor in
creating life in the universe. "Follow the water" is the mantra recited
by astronomers as they search for evidence of life in space. Liquid water, unlike most liquids, is a "universal solvent" that can dissolve an astonishing variety of chemicals. It is an ideal mixing bowl to create
increasingly complex molecules. Water is also a simple molecule that
is found throughout the universe, while other solvents are quite rare.
Second, we know that carbon is a likely component in creating life
because it has four bonds and hence the ability to bind to four other
atoms and create molecules of incredible complexity. In particular, it
is easy to form long carbon chains, which become the basis for hydrocarbon and organic chemistry. Other elements with four bonds do not
have such a rich chemistry.