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Even Steven

In Astro by Brian Koberlein1 Comment

One of the assumptions of cosmology is that at sufficiently large scales the universe is essentially the same everywhere (in formal terms, homogeneous and isotropic).  The basic argument in favor of this cosmological principle is that if the laws of physics are the same everywhere (and we have good evidence that they are) then the way the universe appears is …

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Fire in the Sky

In Astro by Brian Koberlein0 Comments

Sometimes in astronomy a simple question can have a complex answer.  For example, why is the night sky dark?  You might think that has an easy answer:  the sky is dark because the stars are very far away and appear dim.  It’s obvious why the sky is dark, right? Except it isn’t. 

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Air Apparent

In Astro by Brian Koberlein0 Comments

There are now more than 1,000 confirmed exoplanets.  The majority of these planets have been found by the Kepler telescope using what is known as the transit method.  The transit method looks at stars over long periods of time, measuring any changes in the brightness of the star.  If a planet passes in front of the star (transits), then the …

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And Then There Were Four

In Astro by Brian Koberlein1 Comment

Mapping the shape of our galaxy poses quite a challenge.  We are located about two-thirds of the way from the center within the galaxy itself, and there is often dust and gas blocking our view.  To get a really good idea of the shape of our galaxy, you need to make observations at various wavelengths, because each wavelength can give …

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Lost World

In Astro by Brian Koberlein0 Comments

In 1772, Johann Bode noticed a pattern in the distances of the planets from the Sun.  He noted that planets followed a pattern of d = 4 + n, where n was 3, 6, 12, 24, etc.  If you let the Earth’s distance be 10, then Bode’s law matched the distances of the (then) known planets to within a couple …

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The Shape of Things

In Astro by Brian Koberlein0 Comments

Determining the shapes of smaller asteroids is a bit of a challenge.  There are over a thousand asteroids larger than 30 kilometers in diameter, and we simply don’t have the resources to make high resolution images of them.  Worse, some of them are small enough that even observations with the Hubble telescope wouldn’t produce a very clear image. 

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Cold Equations

In Astro by Brian Koberlein1 Comment

The planet Uranus was discovered by William and Caroline Herschel in 1781.  It was the first planet to be discovered (rather than simply being known since the dawn of history), and it was found simply by chance.  Later that year Andrei Leksel calculated the orbit of Uranus and noticed it had some irregularities.  He suggested there may be planets beyond …

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Billions and Billions

In Astro by Brian Koberlein0 Comments

The Gaia mission launched this month with a mission to make a 3D map the Milky Way galaxy. It’s hard to overstate just how large of a task this is.  There are 100 – 200 billion stars in the Milky Way, and Gaia plans to map about 1% of them.  Not just determine their position, but measure their parallax (distance), …

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Every Step You Take

In Astro by Brian Koberlein0 Comments

The distance between the Earth and the Sun is known as an astronomical unit (AU).  It is about 93 million miles, or 150 million kilometers.  Suppose the distance between the Sun and the Earth was the length of your foot (about 30 centimeters).  On that scale the Sun would be the size of a BB just two millimeters wide. At …