Category Archives: Astronomy

Because if it were green, we wouldn’t know where to stop mowing

Why is the sky blue? Everyone supposedly knows, but just about everybody gets it partially wrong. Don’t feel bad, though; the answer has so many parts, it took philosophers and scientists from Aristotle to Maxwell to answer it.

Besides, it’s a bit of a trick question …

Why is the sky blue?

I, Robonaut

Robonaut 2 (on left) became the first nonhuman to visit the International Space Station
Robonaut 2 (on left) became the first nonhuman to visit the International Space Station

Space is as hostile as environments come. Astronauts encounter temperatures that swing from 248 F (120 C) to -148 F (-100 C), and that’s just near Earth. The temperature of deep space plummets to -454 F (-270 C). Even the relative comfort of a space station—with its carefully regulated temperature, pressure and mix of gases—offers no escape from the ravages of prolonged exposure to microgravity.

If ever a setting called for robotic assistance, space is that place; but working in place of and, particularly, alongside humans requires a combination of strength, gentleness and dexterity unequaled by robots found anywhere else. Let’s take a look at …

How Robonauts Work

Fearful symmetry: the beauty and power of tessellations

Irregular pentagon tessellation
Irregular pentagon tessellation. Image by R.A. Nonenmacher

We study mathematics for its beauty, its elegance and its capacity to codify the patterns woven into the fabric of the universe. Within its figures and formulas, the secular perceive order and the religious catch distant echoes of the language of creation. Mathematics achieves the sublime; sometimes, as with tessellations, it rises to art.

How tessellations work

Related Article:
Quiz: Tessellate this!

Beyond the big blue marble

Artist's impression of an exoplanet
Exoplanet visualization by Supportstorm via Wikimedia Commons

Although astronomers and cosmologists long believed in the existence of planets outside our solar system, such worlds remained purely theoretical until as recently as the early 1990s. Since then, the ever-quickening pace of discovery has filled the roster of possible and confirmed planetary candidates with first tens, then hundreds and now thousands of distant worlds.

In this article, I’ll take you on a tour through the history of planet hunting and into its future. Along the way, we’ll take a look at some of the most significant discoveries, including the candidates most suitable for life as we know it.

How planet hunting works

When searching for early galaxies, it pays to look twice

Infant stars
Infant stars (pink) in the Serpens region, captured by NASA's Spitzer Space Telescope (only somewhat relevant, but still cool).

Using NASA’s Hubble and Spitzer Space Telescopes, an international team of astronomers have found nine of the smallest, faintest, most compact galaxies ever observed in the early universe–the building blocks of today’s larger, older galaxies. Composed of millions of brilliant blue stars, each infantile galaxy is one-hundredth to one-thousandth as large as our Milky Way galaxy. They formed about 12.5 billion years ago – just 1 billion years after the “Big Bang.”

Such galaxies are consistent with the conventional model of galactic formation, which holds that larger galaxies are formed when younger, smaller, less-massive galaxies merge. The sighting thus offers some much-needed support for the “hierarchical model,” which has become ever more contentious in recent years.

ASU astronomers help locate obscure galaxies