Archive for the 'Weather & Sky' Category

Feb 07 2015

Flying Saucer?

Published by under Weather & Sky

Lenticular cloud in Hawaii (photo from NASA via Wikimedia Commons)

Whoa!   Is this a flying saucer?

No, it’s a lenticular cloud over Mauna Kea, Hawaii.  This was the Astronomy Picture Of the Day on August 21, 2005.

Click on the image to read more about it.


(photo from Wikimedia Commons. Click on the image to see the original)

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Jan 21 2015

Io! Did You Know… ?

Published by under Weather & Sky

Screenshot of Io video from

Continuing my Jovian January theme …

Yo! Did you know that Jupiter’s moon Io is the most volcanically active world in the solar system?

Io is the size of our Moon but a very inhospitable place.  It’s covered in sulfur which makes pretty shades of yellow but unbreathable air.

To make matters worse, Io is so small and Jupiter is so large that Jupiter’s gravity causes 100 meter land-tides on Io’s surface.  Yes, the land rises and falls 330 feet as Io orbits Jupiter.  No wonder Io has more than 400 active volcanoes!

In 2007 NASA’s New Horizons spacecraft took photos of a plume coming off the top of Io.  What was it?  A volcanic eruption rising 300 miles above Io’s surface!

Click on the screenshot above (or click here) to see a video of Io in action.

Yo, Io!


(video linked from

p.s. Scientists to Io: “Your volcanoes are in the wrong spot.”

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Jan 20 2015

Warmest Year Ever…

Published by under Weather & Sky

Land & Ocean Temperature Departure From Normal, 2014 (image from NOAA's National Climate Data Center)


Last week NOAA’s National Climate Data Center reported that 2014 was the warmest year ever recorded on earth.  Yes, there were undoubtedly warmer years before humans were around and perhaps some warm years before we bothered to write it down but for this century and in our lifetimes, it was hot.

Even after the coldest winter the east-central U.S. can remember, the average U.S. temperature was 0.5 degrees above normal.  (Ask Westerners how hot they were!)  Here’s a month-to-month video that shows that even the East was hot in December.

Climate scientists agree(*) that the warming is caused by humans and there will be sobering results.  We’ve caused it.  We record it.  We report on it.  But will the news change anything?

On a political and media level in the U.S. this news has generated interest and talk but no real action.  On the natural level — among the air, water, birds, plants, and animals that I care about — it is big news and they’re doing something about it.  The air is hotter, the ice is melting, the sea is rising, and the plants, animals and birds are moving north or uphill.

Humans are doing something too, even here in the U.S. where our society has not taken up the cause.

Humans are coping with droughts and building bigger dikes and seawalls.  We’re trying to prevent deaths from frequent heavy downpours.  We’re planting warm-season or drought-resistant flowers and crops.  We’re rewriting insurance policies to exclude disasters that are certain to happen. In some cases we’re already abandoning land that’s altered by flood or drought.

By the end of the century our world will look very different.  Right now the news is “hot.”

Read more here.


(map and video from NOAA’s National Climate Data Center)

(*) That number is “97% of scientists agree.”  Discussion of that number can be found here.  I am not going to discuss the number. Plenty of others have already done so.

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Jan 18 2015

Natural Ice Sculptures

Published by under Hiking,Weather & Sky

Icicles along the Butler-Freeport Trail near Monroe Road (photo by Kate St. John)

A week ago I found beautiful ice formations along the Butler-Freeport Trail at Monroe Road.

Water’s constant drip made a curling fountain.

And some of the icicles accumulated frosty teeth.

Frosty teeth on the icicles (photo by Kate St. John)


The weather was warming that day and part of this massive ice cliff …

Cliff lined with massive icicles (photo by Kate St. John)

… had crashed to the ground across the trail.

Icicles crashed to the ground (photo by Kate St. John)

Here’s one of the smaller chunks near my boot.  I’m glad I wasn’t there when it fell.  Watch out below!

Chunk of fallen icicle for size comparison (photo by Kate St. John)


This weekend the weather has been unseasonably warm.

I wonder what the icicles look like now.


(photos by Kate St. John — taken with my cellphone because I forgot to bring my camera)


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Jan 17 2015

Ice Imitates Art

Ice flows off the Kamchatka coast (photo from the International Space Station via Wikimedia Commons)

Ice off Russia’s Kamchatka Peninsula moves in circles shaped by wind, water and the coast.

Seen from the International Space Station, ice imitates art.


Click here to read more about this photo on Wikimedia Commons.

(photo from the International Space Station via Wikimedia Commons.  Click on the image to see the original)

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Jan 15 2015

A Jovian January

Published by under Weather & Sky

Jupiter and its Galilean moons (image from Wikimedia Commons)

Jupiter has captured my imagination this month so on Throw Back Thursday (TBT) I’m pointing you to one of my favorite January topics:  The Moons of Jupiter.

It’s a Jovian January. 

Watch for another Jupiter post later this month.


(retouched photo of the moons of Jupiter by Don E. Stewart from Wikimedia Commons. Click on the photo to see the original.)

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Jan 13 2015

Me And My Shadow

Published by under Weather & Sky

Io with its shadow on Jupiter (image from Wikimedia Commons)

When the sky is clear on cold January nights, the planet Jupiter shines brighter than the stars.  Step outside with binoculars and you can see up to four of its moons.

These are the Galilean moons, named for Galileo because he was the first to report them in 1610. He used an improved 20-power telescope that wasn’t even as good as today’s birding scopes.  When the moons are in the right position you can see what Galileo saw — something like this.

However on the night of Friday January 23 you’ll need a real telescope to view them because three of the moons — Europa, Callisto and Io — will transit (pass across) the disk of Jupiter and cause eclipses on the planet.

Above, the Hubble Space Telescope captured Io playing “Me and My Shadow.”  At one point on January 23-24 all three moons will play this tune. calls it a triple shadow transit.    Click here for their drawing of what you’ll see in the telescope at 1:40am EST on January 24.

This is your last chance to witness Jupiter’s triple shadow transit until 2032, but it’ll take some preparation and luck to see it.  You’ll need a telescope and the sky has to be clear.

In Pittsburgh we’ll have to cross our fingers.  Our sky is usually overcast in winter.


(photo of Io and its shadow on Jupiter from NASA’s Hubble Space Telescope.  Click on the image to see the original)

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Jan 06 2015

What Are Clippers?

Published by under Weather & Sky

Clipper Ship at Cape Horn by James E. Butterworth (image from Wikimedia Commons)

A fast moving cold front crossed western Pennsylvania yesterday.  The wind roared and temperatures fell from 61 degrees F Sunday morning to 19 degrees yesterday afternoon.  The weather news called it a clipper.

Technically it’s an “Alberta clipper,described by Wikipedia as a fast moving low pressure area that typically affects the central provinces of Canada and parts of the Upper Midwest and Great Lakes.

Clippers start as warm moist wind from the Pacific that crosses the Rockies into Alberta.  When the wind hits cold air on the Canadian prairies it becomes a storm that rides the jet stream on a fast track east.  By the time clippers get to Pennsylvania, Alberta is rarely mentioned.

Though clippers sweep across the continent, they’re regional so if you live outside their zone — say in California, Colorado, or Florida — the word brings to mind the fast-moving sailing ships of the mid 19th century, famous for sailing through dangerous storms at Cape Horn (above).  The weather system is named for the ship.

Yesterday’s clipper left Pennsylvania but now we’re in for real winter — a low of 1 degree F Thursday morning.

Fill your bird feeders!  Birds need food to survive this cold.


(Clipper Ship at Cape Horn, painting by James E. Butterworth, public domain via Wikimedia Commons.  Click on the image to see the original)

p.s.  Here’s what clippers look like on eBay.  😉

Andis hair clippers (for sale on eBay)

(click on the clippers to see the original eBay photo)


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Jan 04 2015

Making Daisies In Outer Space

Published by under Weather & Sky

Precessing Kepler orbit of Earth around the Sun (animation by WillowW on Wikimedia Commons)

Today is the earth’s perihelion, the moment each year when we’re closest to the sun.

Because the earth’s orbit is slightly elliptical, we’re always closest in early January and furthest in July (aphelion), a difference of about 3 million miles.  This sounds like a lot but it’s tiny compared to the size of our orbit.  The distance has no practical effect on our temperature.


When the earth gets close to the sun, the gravitational pull makes us speed up as you can see in the animation.  Right now we’re moving about 1 km/second faster (2,237 mph) than we do in July and this does affect our seasons.  The season surrounding early January (our winter) is 5 days shorter than the season surrounding early July.  This is nice for us but too bad for Australia where their summer is short.

This animation shows our fast and slow progress but its real purpose is to illustrate earth’s orbital precession (in an exaggerated way).

Earth’s orbit is not a closed ellipse.  Instead it tracks out a little further each time as if drawing a huge daisy in outer space without lifting its pencil.  In 21,000 years we come back to where we started and trace the same daisy again.


(animation posted by WillowW on Wikimiedia Commons. Click on the image to see the original with documentation)

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Dec 27 2014

The Cat’s Paw

Published by under Weather & Sky

Cat's Paw Nebula (photo by ESO via Wikimedia Commons)

Seen from the Southern Hemisphere, there’s a cat’s paw in the sky.

The Cat’s Paw Nebula, NGC 6334, was first noted by John Herschel at the Cape of Good Hope in South Africa in 1837.

At -35 degrees declination it’s hard to see this footprint even on a clear night in Pittsburgh.   Cat lovers will have to go south — far south — to get a good look.

This image was taken by the European Southern Observatory (ESO) in Chile.


(photo from ESO via Wikimedia Commons. Click on the image to see the original)

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