Here’s a form of ice we’re unlikely to see in Pittsburgh because our weather is rarely cold enough and it’s often overcast.
Diamond dust is clear-sky precipitation that looks like tiny diamonds in the air, falling through a ground-level cloud. The conditions for producing diamond dust are very specific:
The temperature has to be well below freezing — best at -13F or lower.
The cloud must be made of ice. It’s not a freezing fog that started wet and turned icy.
The cloud is in a clear sky and the sun is shining. That’s how you see the diamonds.
Why does this red-tailed hawk throw up a long gray lump? Is he sick? Not at all. He’s casting a pellet.
Birds’ digestive systems are very different from ours, beginning with their beaks. Since birds don’t have teeth they swallow most of their food whole. The rest of their digestive system is geared to deal with this.
Birds have little saliva and few taste buds compared with mammals, which chew and physically process food as the first step and then subject it to chemical processing as the second step. Birds reverse this sequence. They start chemical digestion in the proventriculus [then the food] undergoes physical processing in the gizzard.
Ornithology, 3rd Edition by Frank B. Gill, page 164
We chew with our teeth and spit out the bones. Birds chew with their gizzards which collect the bones, fur, and other indigestible bits into a lump. The bird spits out the lump when it’s a convenient size.
Owls, eagles, hawks and falcons cast pellets but so do many other birds “including grebes, herons, cormorants, gulls, terns, kingfishers, crows, jays, dippers, shrikes, swallows, and most shorebirds.” (quote from Wikipedia)
Scientists examine pellets to find out what the bird ate. One of the long-eared owl pellets below was dissected to reveal the rodent bones inside.
For whatever reason, it’s rare to see a bird casting a pellet so consider yourself lucky if you witness it, as Chad+Chris Saladin did in the photos above.
A NOTE ABOUT HANDLING OWL PELLETS from Wikipedia: Some rodent viruses and bacteria can survive the owls’ digestive system so wear gloves and sterilize the pellets in a microwave oven before handling. A 2005 study found outbreaks of salmonellosis at elementary schools associated with dissection of owl pellets: Smith KE, Anderson F, Medus C, Leano F, Adams J, 2005. Vector-Borne and Zoonotic Diseases,5, 133–136.
(red-tailed hawk photos by Chad+Chris Saladin; pellet photo from Wikimedia Commons; click on the captions to see the originals)
Last week the news broke that NASA’s New Horizons spacecraft had flown by and photographed what looks like the “snowman of the universe,” two icy chunks stuck together like a snowman and spinning out there in the Kuiper Belt beyond Neptune.
Yes, this object spins. Here’s a time lapse from NASA on New Years Day 2019.
The snowman is reddish and tiny, only 20 miles long, so he can’t be seen from Earth. We wouldn’t even know about him except that a few years ago the New Horizons team looked for something interesting for the spacecraft to explore after it passed Pluto. They saw him as a dot using the Hubble Space Telescope in 2014 and chose him because he’s a classical Kuiper Belt object with low inclination and low eccentricity.
How eccentric is a snowman in outer space? It depends on his orbit.
Ultima Thule’s real name is (486958) 2014 MU69. It’s just the right number of digits for a phone number, but don’t call it. The long distance charges are astronomical!
While looking for something else I found … this beautiful eye of stone. It’s so large that it’s best seen from outer space, as shown in a photo from the International Space Station.
The Eye of the Sahara or the Richat Structure is embedded in the Adrar Plateau near Ouadane, Mauritania. It’s 25 miles across — the distance from Pittsburgh to Greensburg — so people couldn’t see its unusual shape until we could fly above it.
Endogenic means “formed below the earth’s surface.” Indeed the Richat structure is a geologic dome, a magma bubble that hardened before it broke the surface then eroded away to expose the bubble’s onion-like layers. The youngest rock is on the outer edge, the oldest — 600 million years old — is in the center. The rust, blue, and white colors are the different kinds of rock.
Four eggs about to hatch but Hope opens and eats one of them, 17 Apr 2018, 8:11am
Hope has eaten two of the four eggs. One chick hatched, one egg to go, 17 Apr 2018
The coast is clear. Two chicks with Terzo, 19 Apr 2018
Chicks are growing, 28 Apr 2018
We're loud!
Hope defends her young on Banding Day, 11 May 2018
Ready to band
23/BR gets his bands
Hope waits for her chicks to be returned to the nest, Banding Day 11 May 2018
Chicks are back in the nest, Hope stands guard, 11 May 2018
Ooops! One of the chicks is about to get bumped into the gully, 16 May 2018
Growing flight feathers, 17 May 2018
Juvenile plumage, 30 May 2018
Two ledge walkers beg loudly, 27 May 2018
One on ledge, one on the stone peak
Flapping made his wings tired, 29 May 2018
"Mom! Come here!"
Two juvies on the ledge, Hope in the air, 30 May 2018
Juvenile on left, Hope with prey on Heinz Chapel roof, 2 Jun 2018
Hope and Terzo bow at the end of the year, 28 Dec 2018
Peregrine nesting season is only two months away but it feels like an eternity right now. To get in the mood, here are some highlights from the Pitt peregrines in 2018.
Townsend’s solitaire at Yellow Creek, Indiana County, PA (photo by Steve Gosser)
The Townsend’s Solitaire (Myadestes townsendi) is a thrush that lives in western North America, from Alaska to Mexico and only as far east as Nebraska and Kansas in the winter.
He’s considered a short distance migrant but every winter a few individuals break the mold and come to the northeastern U.S. and southeastern Canada. This one was found at Yellow Creek State Park during the Indiana PA Christmas Bird Count on 26 December 2018.
Townsend’s solitaires are easy to identify by their soft gray color, white eye ring, long tail and buffy wing patches. Under certain light conditions his gray color looks brown.
The bird’s common name comes from John Kirk Townsend who first collected it and from its solitary habits. Solitaires are usually alone but will hang out with other species near food. This one was eating fruit with a flock of American robins at the Boy Scout Camp.
Townsend’s solitaire and American robin at Yellow Creek (photo by Glenn Koppel)
Since Townsend’s solitaires are rare in western Pennsylvania, birders from miles around have come to see and photograph him. When I went to Yellow Creek State Park on New Year’s Eve (a 1.5 hour drive) I found the solitaire and six other birders, four of whom I knew by sight or name. I missed Steve Gosser and Glenn Koppel who took these pictures on New Year’s Day.
The bird may be solitary but he generates a crowd.
The definition of a mole will change on 20 May 2019. However, the mammal won’t change, the measure will.
Most of us don’t need to measure the number of atoms, ions, or other tiny entities in a sample of a substance so we’re not aware that the mole (mol) is the unit that does it. Its definition used to be based on 0.012 kilogram of carbon-12 but physical properties can change, so its size could change minutely and throw off precise scientific measurements. This troubled chemical engineers who use the mole extensively.
To fix the problem, the General Conference on Weights and Measures (CGPM) voted at their 16 November 2018 meeting to unlink the mole from its physical definition, redefining it using a mathematical constant. The new definition will be:
One mole of a substance will have exactly 6.02214076×1023 specified “elementary entities” of that substance.
Three other measuring units had the same problem so the meeting redefined four:
Mole: the unit for amount of substance.
Ampere: a unit of electric current equal to a flow of one coulomb per second.
Kelvin: a temperature scale similar to Celsius but 0 degrees K is absolute zero.
Kilogram: the base unit of mass
Perhaps you’ve already heard that the kilogram will change on 20 May 2019. Originally defined as the mass of a litre of water, the kilogram (kg) was redefined in 1799 to be the mass of a block of platinum that’s stored in a vault in Paris. Even the platinum’s mass can change so now the kilogram will be defined by the Planck constant which was defined to be exactly 6.62607015×10-34 kg.m2.s-1. As Wikipedia points out, “This approach effectively defines the kilogram in terms of the second and the metre.”
Notice that the second is raised to minus one, s-1. Is your head spinning? There’s a simpler explanation here in Popular Mechanics.
Meanwhile, why is a hairy-tailed mole (Parascalops breweri) illustrating this article if the message has nothing to do with him? Well, there’s no illustration for the ‘measure’ mole so I’m showing you the ‘mammal’ mole.
(image from Wikimedia Commons; click on the caption to see the original)
This beauty looks like a red-tailed hawk but he’s from Africa. His tail is red but he doesn’t have the telltale “belly band” of dashes on his chest.
This is an augur buzzard (Buteo augur) from Serengeti National Park, Tanzania. Click on the photo caption to see the original featured photo on Wikimedia Commons.
p.s. Augur buzzards have charcoal gray backs and very hooked beaks, but you can’t see those features in this photo.
