Category Archives: Astronomy

How the Summer Solstice Reveals the Big Picture

Because the Earth’s axis is tilted, it passes 4 special points every year. Image credit: By Tauʻolunga – Own work, CC BY-SA 2.5, https://commons.wikimedia.org/w/index.php?curid=927635

I’m on an overseas assignment this month. Yesterday morning, when I walked outside onto the porch, something felt strange. I stepped to the edge and looked up at the overcast sky. A bright area of the clouds bathed my face with heat. Bright heat? How could that be? I faced north. I opened my iPhone’s compass app. Checked. Yep, that was north. But, the Sun never shines from the north. Unless…

I checked the time—10:30 AM. Then the date—June 20th. I knew I was north of the equator, so only one explanation remained. What I observed meant I was standing south of the Tropic of Cancer. Sometime during the next day or two, the Earth, on its way around the Sun, would pass a point called the Summer Solstice. read more ...

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Lagrange Points—Orbits to Nowhere

Milky Way in night sky above a lake shore

Without gravity, everything we see here—water, trees, rocks, and stars—would fly apart

Gravity glues our universe together. Without it, neither we nor any life could exist. The Earth spins at just over 1,000 miles per hour at the equator. Without gravity, anything loose on the surface like water, cars, picnic tables, and people would immediately fly off into space. Without gravity, Earth couldn’t keep an atmosphere. As soon as it drifted free from the surface, the fierce solar wind would blast it away. Without gravity the Sun itself would expand, dissipating in a fine, cold mist of dust and gas.  read more ...

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Pluto Reveals Another Life Secret

image of Pluto shot from New Horizons space probe

Imagination inspires us. What could be, grows into vision. Vision draws us, taunts us, challenges us to stretch beyond our ability. We go to super-human extremes to realize dreams based on nothing more solid than an idea, hunch, or wish.

On the other hand, our concepts of real, but unvisited, places often remain vague. They lack solidity, vibrance, and complexity almost as if they don’t exist at all. We try to imagine what we’ve never seen but reality usually surprises us.

Take NASA’s New Horizon space probe for example. Clyde Tombaugh finally found Pluto in 1930 after an exhaustive search. Since then many wondered what the faraway planet might look like, might be made of. In the intervening years, most of us settled with the hazy picture of yet another cratered but otherwise unremarkable rock moving along its lonely path around the solar system. read more ...

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Shadow Dance of the Eclipses – Handling Light (updated)

Early part of 21 August 2017 solar eclipse

Photo of a projection onto a screen through a telescope of the early part of the 21 Aug 2017 eclipse. Two groups of sunspots are visible—a cluster of three near the center, and a cluster of two near the bottom edge.

Eclipses come in two varieties. The first kind occurs because our moon is the solar system’s odd duck.

For example, it travels a special orbit. Like ballroom choreography that looks simple until close inspection, the Moon only appears to orbit the Earth. In fact, it orbits the Sun. The Earth, 80 times heaver than the Moon, moves steadily on its course about the Sun. But the Moon weaves rhythmically either side of the Earth’s orbit, first outside farther from the Sun, then in front of the Earth, then inside closer to the Sun, and then trailing the Earth. The two dancers interlock gravity arms and sway in 29-day rhythm. read more ...

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Coming to the Wild Point of View

Amateur astronomers standby telescopes waiting for dark

Observers set up equipment in the last light of day, then wait for dark

Cool desert evening. Clear sky. Sun crossed the horizon a few minutes ago as my friend, Bob, and I head towards the Snake River south of Boise, Idaho. The Owyhee mountains stretch across the horizon before us. Around us flat rolling grassland slowly descends to the river, but just a mile short we arrive at Dedication Point—a ubiquitous dessert historical site complete with parking area, restroom, intense quiet, unobstructed view in every direction, and, most importantly, the promise of dark sky. read more ...

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