Stories tagged sun

Saturn rings on Earth?: What would the sky look like if Earth had rings like Saturn? This shows the scale of those rings in Washington, D.C. and other points across the globe.
Saturn rings on Earth?: What would the sky look like if Earth had rings like Saturn? This shows the scale of those rings in Washington, D.C. and other points across the globe.Courtesy Ron Miller
Just from watching the opening of Star Trek episodes, we've heard that space is vast. But to we really understand the scale of things comparing our little planet with other planets, stars and galaxies? This collection of illustrations helps grasp those concepts better. Hang on tight!


Lunar eclipse: Tonight's will be the first in a tetrad of four total lunar eclipses over the next year-and-a-half.
Lunar eclipse: Tonight's will be the first in a tetrad of four total lunar eclipses over the next year-and-a-half.Courtesy Mark Ryan
The first of 4 consecutive total lunar eclipses occurs late tonight (and early Tuesday morning) and will be visible to practically all of the United States (local weather permitting). The astronomical event begins around 5:58 UT, and should last about 4 and a half hours from start to finish.

A total lunar eclipse takes place when the moon passes through the Earth's umbra, the innermost darkest shadow created by the Earth as it (from the Moon's perspective) blocks out the Sun. Refraction caused by the Earth's atmosphere allows for some of the Sun's light to bend around the Earth and bathe the Moon in an amber glow, resulting in what is sometimes referred to as a Blood Moon, especially by some fundamental religious groups who see it as an omen of the biblical End Times. There are two other kinds of lunar eclipses. When the Moon passes only through the penumbra, the faint part of the shadow, that's called a penumbral lunar eclipse. When only a portion of the Moon intersects with the darker umbra, that's a partial lunar eclipse.

As I mentioned, tonight's eclipse is the first in a series of four consecutive total lunar eclipses. This is a pretty uncommon occurrence known as a tetrad. Only 62 tetrad events will have occurred from 1 A.D. to the year 2100, and just eight in the 1200 months of the 21st century.

Each year there are at least two lunar eclipses and sometimes as many as five. Eclipses don't happen every month because the plane of the Moon's orbit around Earth is tilted. Usually, consecutive eclipses are a mix of partial, penumbral, and the relatively rarer total lunar eclipses. To have four total lunar eclipses happen in a row, as we will over the next seventeen months or so is even rarer. And luckily, all four of them be will visible to most of us in the United States.

Tonight's celestial event begins at 11:55 PM (Minneapolis time) and reaches maximum eclipse at 2:46 AM, then finishes at 4:32 AM. If you want to confirm the times for your area, use this handy eclipse calculator. The night-owl timing of tonight's eclipse might keep many of you from enjoying it (I'll probably be sleeping), but just know there are three more headed our way: October 8, 2014, April 4, 2015, and September 28, 2015.

NASA Eclipse Web Site
Eclipse expert Fred Espanek's Lunar Eclipse Primer
Universal Time (UT) conversion table
Observing tips at
Eclipse visibility maps at

A major eruption on the Sun on June 7 sent high-energy particles spewing into space. They are expected to reach Earth on the night of Wednesday June 8 (Minnesota time). Astronomers are predicting a major aurora event, with the Northern Lights visible overhead as far south as Milwaukee, and possibly visible on the northern horizon as far south a southern Indiana and Washington DC! For Buzzers in the northern US / southern Canada, if the sky is clear tonight, go out, find a dark place away from city lights, face north and look up. No telescopes or other fancy equipment needed. You can even try to photograph them (use a long exposure, no flash, and set the camera on something steady.) If you get any photos, post them here in the comments.

For more info, and up-to-the-minute predictions, visit the Aurora Forecast page.

Aurora alert

by Gene on Dec. 15th, 2010

According to the Aurora Alert mailing list, a solar event on Dec 14th may produce auroral displays (northern lights) starting around midnight tonight, Wednesday 12/15, and continuing Thursday 12/16 and possibly Friday 12/17. Your best bet for seeing the lights -- if they occur -- is to get away from the city, find a dark place with a clear view to the north, and look low on the horizon. Clouds will block your view, so if it's overcast, don't bother.

Great Ball of Fire
Great Ball of FireCourtesy NASA/SDO/AIA
Today's image of the day from NASA is super sweet, I wanted to share it.

From the Image of the Day site:

On August 1, 2010, almost the entire Earth-facing side of the sun erupted in a tumult of activity. This image from the Solar Dynamics Observatory of the news-making solar event on August 1 shows the C3-class solar flare (white area on upper left), a solar tsunami (wave-like structure, upper right), multiple filaments of magnetism lifting off the stellar surface, large-scale shaking of the solar corona, radio bursts, a coronal mass ejection and more.

This multi-wavelength extreme ultraviolet snapshot from the Solar Dynamics Observatory shows the sun's northern hemisphere in mid-eruption. Different colors in the image represent different gas temperatures. Earth's magnetic field is still reverberating from the solar flare impact on August 3, 2010, which sparked aurorae as far south as Wisconsin and Iowa in the United States. Analysts believe a second solar flare is following behind the first flare and could re-energize the fading geomagnetic storm and spark a new round of Northern Lights.

It's Friday, so it's time for another Science Friday video. Science Friday
Science Friday
Courtesy Science Friday
NASA's Solar Dynamics Observatory (SDO), launched in February, has started to send back data. The instruments are giving solar scientists an unprecedented look at the sun, says Dean Pesnell, SDO project scientist. The hope is to better understand how solar activity--solar flares, coronal mass ejections, coronal holes--is linked to the sun's magnetic field.

Sun with sunspots
Sun with sunspotsCourtesy NASA

One of the most common questions I hear about climate change is "Isn't it just the sun?" Days (sun out) are warmer than nights (no sun), and sunny days are usually warmer than cloudy days. Let's be honest, it would also be much easier on the conscience. After all, we have about as much chance of controlling the sun as I do of getting my cat to do the laundry. But our actions do impact the amount of carbon dioxide in the atmosphere.

Scientists who are interested in climate have been looking into this. A new paper by Anja Eichler and her colleagues from Switzerland and Russia looks at this problem by comparing records of how brightly the sun has been shining to the temperature in central Asia over the last 750 or so years. Now you're probably thinking, "Hey, who had a thermometer in Siberia 750 years ago?" It turns out that the part of Siberia near Mongolia and Kazakhstan has glaciers that are actually pretty good at recording the temperature.

So what'd they find? The sun is pretty important. It explains well over half of the wiggles in the temperature curve . . . until 1850. After that the sun is still kind of important, but changes in the amount of carbon dioxide in the atmosphere do a much better job explaining the recent warming.

Other scientists have found the same story using different methods, so I think we're homing in on a solid answer.

If you want to read the paper yourself, it is in press in Geophysical Research Letters. The story's not free on-line, so you might need to head to a library to check it out.

Investigations into the 2007 collapse of the I-35W bridge are wrapping up and being reported. Here's an interesting report on what role the sun and its energy may have played in the timing of the bridge's collapse on that fateful Aug. 1 day. Oh, and my apologies to Elton John for swiping his lyrics for the headline of this post.


Where, oh where, have my sunspots gone?: Sunspot activity tied a record low of zero in August, 2008.
Where, oh where, have my sunspots gone?: Sunspot activity tied a record low of zero in August, 2008.Courtesy NASA

For the first time in almost a century, the Sun has a spotless record. There were no observed sunspots in August. None. Zero. Zip. Can't get a record any lower than that. That's the first time this has happened since 1913.

That's before commercial radio. Before talking movies. Before World War I. Why, it's almost as long as since the last time the Cubs won the World Series.

Now, that's a long time!

Plus, as we've discussed before, the Sun has been unusually quiet of late. Sunspots generally go through an 11-year cycle, and we're a couple years late for the next rise in activity.

But, you are no doubt wondering, what does this mean to me, the Average Joe? (Assuming your name is indeed "Average Joe," which would be pretty remarkable and, ironically, not average.) Well, sunspots seem to be tied to weather. Three times, since astronomers began observing suspots, has the Sun fallen silent, and each time coincides with significant drops in global temperatures. One such dip, from roughly 1600 to 1750, was so severe it is known as "The Little Ice Age."

Are we heading into another glacial period? Much too soon to tell. But if you start feeling chilly, keep your eye on the Sun. Astronomers will be doing the same.

(NOTE FOR THE METAPHORCALLY-IMPAIRED: That was meant figuratively. Do not look directly at the Sun with your naked eye. You'll burn out your retina.)


Is it hot in here, or is it just me.: Research and debate continues on global warming. Image by ! "S4N7Y" !
Is it hot in here, or is it just me.: Research and debate continues on global warming. Image by ! "S4N7Y" !

(With the Republican National Convention literally across the street, the Science Museum of Minnesota will be closed starting Friday, August 29. But Science Buzz marches on! To honor our convention guests, I’ll be posting entries focusing on issues where science and politics overlap. Hopefully this will spur some discussion. Or at least tick some people off.)

Let’s start with a nice, safe topic. Like global warming. Because Lord knows, we haven’t discussed that enough.

We recently passed an important milestone in the climate change debate: it was 20 years ago this summer that global warming became a political issue in America, thanks to NASA’s Jim Hansen testifying before Congress. (Some wags have noted that the global temperature in June 2008 was cooler than in June 1988--but that’s weather, not climate.)

There was a dust-up recently concerning the American Physical Society, a leading scientific organization. One of its units, the APS Forum, published a paper by Christopher Monckton arguing that carbon’s impact on climate has been greatly overstated. The Forum intends to publish additional papers in its journal, Physics and Society, as part of a public debate on global warming science.

Some in the news media inaccurately reported that the APS itself had reversed its stance on global warming. This was not the case—the society as a whole maintains that human activity is the main cause of recent climate change. The journal is put out by APS Forum, which is just one of 19 units within the larger organization. But at least they are willing to have the debate.

Meanwhile, Australian astronomer Ian Wilson is predicting global cooling. His research finds that the main driver of Earth’s climate is the Sun’s activity, and that has been decreasing of late.