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We Three Kings

In History by Brian Koberlein1 Comment

One of the classic images of the Christmas holiday is that of three wise men or kings traveling to Bethlehem, over which hangs a brilliant star. The Star of Bethlehem has its roots in the opening verses of the Gospel of Matthew, which states: Read More

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And Proxima Makes Three

In Stars by Brian Koberlein0 Comments

If you ask someone to name the closest star, Alpha Centauri is perhaps the most common answer. Some will recognize it as a trick question and correctly answer “the Sun,” but the closest star to our Sun is a faint star known as Proxima Centauri. One of the long-standing questions is whether Proxima is actually part of the Alpha Centauri system, or whether it just happens to be in the same general vicinity. We now have a pretty solid answer. Read More

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Through The Looking Glass

In Physics by Brian Koberlein3 Comments

Hydrogen is the most abundant element in the Universe. It consists of a single proton paired with an electron. Since the proton and electron are bound together, the electron must reside in particular energy states. When the electron transitions from a higher energy state to a lower one, it releases light with a specific color. Each energy transition for the electron corresponds to a particular color, and together they form the emission spectrum of hydrogen. All atoms have nuclei of protons and neutrons bound to electrons, and the resulting emission spectra allow us to determine what makes up distant objects. It’s one of the most powerful tools in astronomy. Read More

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Phantom Time

In History by Brian Koberlein2 Comments

In my last post, I talked about how historians can help us understand aspects of astronomy, such as the rate at which Earth’s rotation is slowing. The same thing can happen in reverse, where astronomy can confirm aspects of history. Take, for example, the Early Middle Ages, and the theory of phantom time. Read More

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Wonderful Precision

In Astronomy by Brian Koberlein1 Comment

On August 21 of 2017 the shadow of the Moon will trace a path across the United States. It’s a total solar eclipse that many will have the opportunity to observe. But whether you will observe totality or not depends on where you are. Astronomers have been able to predict the path of solar eclipses for millennia, but this new video demonstrates just how precise our predictions have become. Read More

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The Pace Of Time

In History by Brian Koberlein2 Comments

A day on Earth is longer than it used to be. The increase is tiny. Over the span of a hundred years the Earth’s day will increase by only a few milliseconds. It’s only been in the past few decades that we’ve been able to measure Earth with enough precision to see this effect directly. Using atomic clocks and ultra-precise measurements of distant quasars, we can measure the length of a day to within nanoseconds. Our measurements are so precise that we can observe various fluctuations in the length of a day due to things like earthquakes. Those fluctuations make it a challenge to answer another question. How has Earth’s rotation changed over longer periods of time?  Read More

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Black Holes, Bright Lights

In Black Holes by Brian Koberlein0 Comments

Supernovae are the bright, but short lived explosions of a dying star. At their brightest they can outshine an entire galaxy. The brightest ones, known as superluminous supernovae, can be more than 10 times brighter than type Ia supernovae used to measure the distances of far galaxies. But there’s a limit to how bright a supernova can be, so when we observed a supernova last year that seemed to exceed that limit, it raised an interesting question. Is our model of superluminous supernovae wrong, or is something else going on? Read More

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A Light Change

In Cosmology by Brian Koberlein6 Comments

One of the big mysteries of modern cosmology is the fact that the Universe is so uniform on large scales. Observations tell us our Universe is topologically flat, and the cosmic microwave background we see in all directions has only the smallest temperature fluctuations. But if the cosmos began with a hot and dense big bang, then we wouldn’t expect such high uniformity. As the Universe expanded, distant parts of it would have moved out of reach from each other before there was time for their temperatures to even out. One would expect the cosmic background to have large hot and cold regions. The most common idea to explain this uniformity is early cosmic inflation. That is, soon after the big bang, the Universe expanded at an immense rate. The Universe we can currently observe originated from an extremely small region, and early inflation made everything even out. The inflation model has a lot going for it, but proving inflation is difficult, so some theorists have looked for alternative models that might be easier to prove. One recent idea looks at a speed of light that changes over time.Read More

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Doing The Wave

In Physics by Brian Koberlein1 Comment

There has been a lot of digital ink spilled over the recent paper on the reactionless thrust device known as the EMDrive. While it’s clear that a working EM Drive would violate well established scientific theories, what isn’t clear is how such a violation might be resolved. Some have argued that the thrust could be an effect of Unruh radiation, but the authors of the new paper argue instead for a variation on quantum theory known as the pilot wave model. Read More