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.
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.
This topographic reconstruction from satellite photos shows how the Eye is a bullseye bowl in the desert plateau.
In the end, it’s visible because it’s in the Sahara. No vegetation covers it and the wind has blown all the sand away.
(images from Wikimedia Commons and a video by Jeffrey Sonders; click on the captions to see the originals)
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.
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)
Two million years ago the Monongahela was a mighty river. Instead of being a short tributary of the Ohio and draining to the Gulf of Mexico, it flowed north to where Lake Erie is today and then to the Atlantic. This stretch of the Ohio River in Pittsburgh was not the Ohio at all. It was the Monongahela.
Here’s how the mighty Mon River lost its crown and the reason why the Ohio turns south at Beaver, Pennsylvania.
Before the Pleistocene era, the Monongahela River drained 75% of today’s Ohio, Allegheny and Monongahela watersheds as it flowed north from West Virginia to the Lake Erie area (roughly the red arrow path below).
Back in those days the Ohio River was just a tributary whose northernmost point was in Pennsylvania where it joined the Mon. The Beaver and Shenango Rivers did not exist as they do today. Their valleys carried the Monongahela north.
But then the climate changed. The Great Ice Age began.
Glaciers blocked the Monongahela’s northward flow so the river backed up and formed Lake Monongahela. The pale dashed lines show the paths of our rivers today bending away from the prehistoric glacier.
Eventually Lake Monongahela rose so high that it breached the lowest barrier in the Ohio valley near present day New Martinsville, WV (see orange arrow).
The Ohio started flowing “backwards.” It cut the Ohio River valley deeper, orphaned the northern Monongahela and reversed its flow, creating the Shenango and Beaver Rivers.
All of this was helped by the huge volume of water joining the Mon from the re-formulated Allegheny River watershed. The Upper and Middle Allegheny river systems used to flow north too, but were also blocked by glaciers. Their proglacial lakes overflowed and joined the Lower Allegheny River flowing into the Ohio watershed.
And so the Monongahela River became a lowly tributary of the Ohio.
Climate change is big stuff. When it gets cold it changes major rivers. When it gets hot … Well, we’ll find out.
UPDATE: See the comments! And here’s a map of the ancient Erigan River drainage from Ohio DNR.
(photo by Kate St. John. Red-arrow map derived from OH & PA river maps at geology.com, map of Lake Monongahela from Wikimedia Commons, annotated map of Erigan River via CVNP; click on the captions to see the originals)
The study found mercury in harlequins from both locations but those at Unalaska, midway in the Aleutian chain, had eight times more than those at Kodiak, nestled in the Gulf of Alaska. The study then tested the ducks’ main food at Unalaska — blue mussels — and found it there, too.
Mercury apparently increases westward in the Aleutian chain. A 2014 study found mercury in fish above the human consumption limit at the western island of Agattu.
Where is the mercury coming from? In the continental U.S. airborne mercury comes from coal-fired power plants and is regulated and reduced by the EPA. It can also come from active volcanoes, obviously out of our control.
At this point scientists don’t know where the mercury is coming from, but China’s coal-fired industries are a good bet. The prevailing wind in the Aleutian Islands originates in Asia more than six months of the year.
Unfortunately Alaskans can’t prevent mercury pollution that reaches them from Asia. Meanwhile the harlequins warn of danger.
(photo of harlequin duck from Wikimedia Commons, screenshot of global winds from earthvisualization website; click on the caption links to see the originals)
In all the smoke-filled photos of the Camp Fire devastation in Paradise, California one thing stands out to me: The buildings are gone but the trees are still standing.
The town of Paradise, California (population 26,000) was destroyed on 8 November 2018 by the Camp Fire, the deadliest and most destructive fire in California history. As soon as it ignited at 6:30am, the fire raced westward on 50-70 mph winds. By 8am it reached the Paradise Town Limit six miles away. Seven towns were forced to evacuate but not everyone made it out. As of 26 November, 88 are confirmed dead, 203 are still missing and tens of thousands are left homeless.
In the winter huge flocks of starlings line up on the electric wires. They even perch on un-insulated wires like those shown above. Why don’t they get electrocuted?
Here’s some helpful background: Electricity is the flow of electrons in a complete circle — called a “circuit” — that moves out from the power source, into our appliances, and all the way back to the power station. The electrons flow in the path of least resistance.
The Youghiogheny River is famous for whitewater rafting near Ohiopyle but there’s a tributary downstream where white water is bad.
On the GAP Trail north of Buena Vista — near marker 121 — you can hear a rushing waterfall before you see it. When you reach its location it’s not a pretty sight. The waterfall stains everything white.
Early this month I looked at the water and its outflow in the Youghiogheny River and discovered that the water is clear and colorless, though it leaves a white residue on everything it touches.
Here are some closer looks.
The water is clear because it’s acidic. The residue is from abandoned mine drainage (AMD), a problem that pollutes more than 2,500 miles of Pennsylvania rivers and streams.
As water from the abandoned mine travels downhill it blends with clean water that raises the pH (i.e. lowers the acidity). At some point the diluted mine water isn’t acidic enough to dissolve aluminum sulfate so the aluminum precipitates out as white residue.