To Scale, The Last Planet

A vintage NASA-commissioned Rick Guidice painting gives a cutaway view of the inside of a space colony design known as the Stanford torus, a proposed habitat that would house 10,000 to 140,000 permanent residents. The rotating, doughnut-shaped ring could have a diameter of around 2 kilometers, revolving once per minute to give about 1.0g of artificial gravity on the inside of the ring through centripetal force. A massive system of mirrors would provide the sunlight needed for daily activity, agriculture, and so forth. (NASA Ames Research Center)

Vote for Place of the Year 2015

Was 2015 the year of Pluto? Or does its exit from the Eurozone make Greece Place of the Year? Now is the time to vote and tell us which place made the most history this year.

In the meantime, reflect on 2014 Place of the Year, Scotland.

Image: Public Domain via Wikimedia Commons.

Hey Venus

Stunning, trippy 1970s NASA concept art for future space colony designs. Available (plus many more) in super hi-res here (and copyright free), for all your desktop wallpaper and/or prog-rock album cover needs. (via io9)

Here's What 10 Million Stars Look Like

Using the Dark Energy Camera at the Cerro Tololo observatory in Chile, astronomers took an image of the stars clustered around the center of our Milky Way galaxy that shows about 10 million stars. Check out the zoomable version for the full experience.

Looking at an image like this is always a bit of a brain-bender because a) 10 million is a huge number and b) the stars are so tightly packed into that image and yet c) that image shows just one tiny bit of our galactic center, d) our entire galaxy contains so many more stars than this (100-400 billion), and e) the Universe perhaps contains as many as 2 trillion galaxies. And if I’m remembering my college math correctly, 400 billion × 2 trillion = a metric crapload of stars. (via bad astronomy)

Circling the Sun (Mercury meets Venus)

The Sirens of Titan

Apart Together

October 31, 2000 was the last day all humans were together on Earth. That day, the rocket containing the crew of Expedition 1 lifted off from the Baikonur Cosmodrome in Kazakhstan and carried them to the International Space Station for a long-term stay. Fittingly, the mission left from the same launchpad that was used to launch Yuri Gagarin into space on April 2, 1961, which was the first time in history that all humans were not together on Earth. Ever since the Expedition 1 crew docked, there’s been an uninterrupted human presence on the ISS, which may continue until 2028 or 2030, by which time there may be humans on the Moon or Mars on a permanent basis. Will humans ever be only Earth-bound again?

BTW, I guess you could argue that the ISS isn’t really separate enough from Earth or that since regular commercial airplane flights began, humans have been separate from the Earth. You could also say that at any given time, thousands of people are in the air while jumping and therefore not on the Earth with the rest of us. I don’t find any of those arguments meaningful. Perhaps someday if space travel is more routine – “just popped up into orbit to visit my daughter” – and the human population is much more distributed, these same distinctions won’t hold, but for now the ISS is definitely apart from the Earth in a way that flying or jumping are not.

Celestial Geometry: Equinoxes and Eclipses

March 20 marks the spring equinox. It’s the first day of astronomical spring in the Northern Hemisphere, and one of two days a year when day and night are just about equal lengths across the globe.

Because Earth is tilted on its axis, there are only two days a year when the sun shines down exactly over the equator, and the day/night line – called the terminator – runs straight from north to south.

In the Northern Hemisphere, the March equinox marks the beginning of spring – meaning that our half of Earth is slowly tilting towards the sun, giving us longer days and more sunlight, and moving us out of winter and into spring and summer.

An equinox is the product of celestial geometry, and there’s another big celestial event coming up later this year: a total solar eclipse.

A solar eclipse happens when the moon blocks our view of the sun. This can only happen at a new moon, the period about once each month when the moon’s orbit positions it between the sun and Earth — but solar eclipses don’t happen every month.  

The moon’s orbit around Earth is inclined, so, from Earth’s view, on most months we see the moon passing above or below the sun. A solar eclipse happens only on those new moons where the alignment of all three bodies are in a perfectly straight line.

On Aug. 21, 2017, a total solar eclipse will be visible in the US along a narrow, 70-mile-wide path that runs from Oregon to South Carolina. Throughout the rest of North America – and even in parts of South America, Africa, Europe and Asia – the moon will partially obscure the sun.

Within the path of totality, the moon will completely cover the sun’s overwhelmingly bright face, revealing the relatively faint outer atmosphere, called the corona, for seconds or minutes, depending on location.

It’s essential to observe eye safety during an eclipse. Though it’s safe to look at the eclipse ONLY during the brief seconds of totality, you must use a proper solar filter or indirect viewing method when any part of the sun’s surface is exposed – whether during the partial phases of an eclipse, or just on a regular day.

Learn more about the August eclipse at eclipse2017.nasa.gov.

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