Saturday, October 25, 2014


NASA's unmanned Lunar Orbiter 1 gave us an unprecedented image of Earth rising above the lunar surface in 1966.

Today, 17595 days after the first Earthrise image, the Moon has made 644 trips around Earth.

The Moon orbits Earth every 27.322 days. As the Moon orbits Earth, it synchronously rotates on its axis.

The Moon rotates 360° in 27 days. Because the Moon orbits Earth every 27.322 days, it exposes the same face to an Earthbound observer.

Near Side Far Side

The face of the Moon we see is called the near side. The opposite side is called the far side, or the dark side. Dark side is a misnomer because when the Moon is dark during a new phase, the far side is bathed in sunlight.

31 Moon orbits after the 1966 Lunar Orbiter 1 gave us the iconic image of Earth rising above the lunar horizon, Apollo 8 astronauts were orbiting around the Moon in December 1968.
Earthrise Above Lunar Surface
August 23, 1966
"I happened to glance out of one of the still-clear windows just at the moment the earth appeared over the lunar horizon. It was the most beautiful, heart-catching sight of my life, one that sent a torrent of nostalgia, of sheer homesickness, surging through me. It was the only thing in space that had any color to it."
Frank Borman, Commander of Apollo 8

The Apollo 8 astronauts were the first people to leave Earth's orbit; the first people to see the whole Earth; and the first people to see the far side of the Moon.
In space there are countless constellations, suns and planets; we see only the suns because they give light; the planets remain invisible, for they are small and dark. There are also numberless earths circling around their suns.”
Giordano Bruno, Despre infinit univers si lumi, 1584.


Saturday, October 18, 2014

Deep Time

Einstein mused about the illusive nature of distinguishing past, present, and future.
"People like us, who believe in physics, know that the distinction between past, present, and future is only a stubbornly persistent illusion."
Albert Einstein
An eon in common parlance, is a very long period of time:
e·on/ˈēən,ˈēˌän/ indefinite and very long period of time, often a period exaggerated for humorous or rhetorical effect.
usage: She reached the hilltop cairn eons before my arrival.
An eon acquires the specificity a billion years for geologists and astronomers. Radiometric dating indicates Earth is 4,540,000,000 years old. This translates to about four and one half eons.
“Four days will quickly steep themselves in nights;
Four nights will quickly dream away the time.”

William Shakespeare, A Midsummer Night's Dream

Deep Time

by Hansueli Krapf
Earth is roughly 57 million times older than the longest average human life expectancy. Perhaps the 56,750,000-fold difference explains why geologic time is baffling.

Geologic time is also referred to as deep time.

Comparing deep time to human time in Basin and Range, John McPhee borrows a metaphor cited from Stephen Jay Gould's Time's Arrow, Time's Cycle:

Consider the Earth's history as the old measure of the English yard, the distance from the King's nose to the tip of his outstretched hand. One stroke of a nail file on his middle finger erases human history.

Some geologic phenomena occur in real-time like the calving of a glacier, the flow of lava from a volcano, or the formation of a tropical cyclone.

Most geologic phenomena occur on a geologic time scale like continental drift — for example the pulling apart of the North American and Eurasian Plates at Þingvellir in southwestern Iceland.

Geologists have trained themselves to imagine events unfolding in units of time no smaller than a million years. The intersection of human time and geologic time excites our curiosity.
“If you free yourself from the conventional reaction to a quantity like a million years, you free yourself a bit from the boundaries of human time. And then in a way you do not live at all, but in another way you live forever.”
John McPhee, Annals of the Former World

Image: Tobias Alt

"The mind seemed to grow giddy by looking so far into the abyss of time."
John Playfair, remarking on the strata of the unconformity at Siccar Point

If one lives to be 100 years old, Earth will still be some 45 million years older.


Saturday, October 11, 2014

Fish Migration

Photo by Matthew Hoelscher
Many marine fish regularly migrate over distances ranging from a few meters to thousands of kilometers. The migration time scale ranges from daily to annually, or longer.

Significant long-term fisheries migrations are likely to occur due to the impact of climate change on ocean temperatures.

Marine Biologists predict a large-scale poleward shift of marine fish and invertebrates using measurable data and computer simulations known as species distribution models (SDM).
"As fish move to cooler waters, this generates new opportunities for fisheries in the Arctic. On the other hand it means it could disrupt the species that live there now and increase competition for resources.”
― Miranda Jones, a University of British Columbia Nereus Fellow

Worst Case Best Case
Earth’s oceans warm by 3° C by 2100Earth’s oceans warm by 1° C by 2100
Fish migrate poleward from current habitats at a rate of 26 km (16 miles) per decade.Fish migrate poleward from current habitats at a rate of 15 km (9 miles) per decade.

“So there is a kind of terrible irony that at the point that we are best able to understand and appreciate and value the richness of life around us, we are destroying it at a higher rate than it has ever been destroyed at all.”
Douglas Adams, excerpt from Parrots, the Universe and Everything

Three SDMs AquaMaps, Princeton's Maxent model, and the Dynamic Bioclimate Envelope Model were used by Miranda Jones and William Cheung from the University of British Columbia Fisheries Centre to analyze the world oceans and predict patterns of change in fish species:

Atlantic Bluefin Tuna
Photo by Danilo Cedrone

“The tropics will be the overall losers. This area has a high dependence on fish for food, diet and nutrition. We’ll see a loss of fish populations that are important to the fisheries and communities in these regions.”
― William Cheung, University of British Columbia Fisheries Centre


Saturday, October 4, 2014

Mountains of the Deep

Seamounts are the mountains of the deep. A seamount is typically an extinct submerged volcano that has risen from the seafloor.

The New England Seamount Chainin the Atlantic Ocean

Bear Seamount - oldest seamount in the New England Seamount Chain

If enough volcanic material erupts, and the material is amassed atop itself, a seamount can rise above sea level to become a high island like the Hawaiian Islands.

Many volcanoes go dormant or become extinct to remain seamounts below sea level.
“We are like islands in the sea, separate on the surface but connected in the deep.”
William James
Seafloor mapping missions are still discovering new seamounts.
“What is wanted is not the will to believe, but the will to find out, which is the exact opposite.”
Bertrand Russell
Gravity fields recorded by the NASA Jason-1 satellite, combined with gravity measurements from the ESA CryoSat-2 satellite, have enabled scientists to map thousands of previously uncharted seamounts.

Seamount southeast of Jarvis Island
Last August, while delineating the extent of the U.S. continental shelf in the Pacific Ocean using a multi-beam echosounder, scientists discovered a 3,600 ft seamount 186 miles southeast of Jarvis Island in the South Pacific.

“We shall not cease from exploration
And the end of all our exploring
Will be to arrive where we started
And know the place for the first time.”
T.S. Eliot, Four Quartets