Stories tagged earth

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!

Apr
14
2014

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.

SOURCES and LINKS
NASA Eclipse Web Site
Eclipse expert Fred Espanek's Lunar Eclipse Primer
Universal Time (UT) conversion table
Observing tips at Space.com
Eclipse visibility maps at Space.com

The flyby of asteroid 2012 DA14 on Feb. 15, 2013, will be the closest known approach to Earth for an object its size, but there is no chance it will hit Earth.

Jan
08
2013

More Earths on the horizon?: Who knows how many potential new Earths are out there circling other stars in the Milky Way?
More Earths on the horizon?: Who knows how many potential new Earths are out there circling other stars in the Milky Way?Courtesy NASA
We like to think of our home planet – Earth – as a pretty unique place. It's the only planet in our solar system capable of sustaining life. We look through telescopes and to see exotic looking planets of various sizes and shapes. But we're the one and only Earth, right?

A new census of planets in the Milky Way galaxy shakes up that thinking. New data collected by NASA's Kepler spacecraft pegs one in six stars in the Milky Way of having planets that are the same size as Earth. That one-sixth fraction translates into an estimate of about 17 billion planets that are the same approximate size as our home.

So we're not as exclusive as might like to think. But the exclusivity meters edges back toward us when you factor in the Goldilocks zone – a distance from the host star that's not too hot nor too cold to sustain life. So far, extended research on the new-found planets has identified only four Earth-sized planets that could possibly reside in a Goldilocks zone. The Kepler project has identified a total of 2,740 potential new planets with more research ongoing.

Oct
16
2012

A plankton bloom: Not the new bloom off of Canada, but this is what it looks like. The green stuff in the water is sucking up carbon dioxide and doing ... we don't know exactly what else yet.
A plankton bloom: Not the new bloom off of Canada, but this is what it looks like. The green stuff in the water is sucking up carbon dioxide and doing ... we don't know exactly what else yet.Courtesy NASA
Have you ever wanted to change the world? Of course you have. Who hasn’t? Even JGordon, world renowned for being more or less satisfied with his immediate surroundings, keeps a list of Things I Will Change When I Am King.

Some sample items from the list:
31: No more cake pops. What a joke.
54: Round up the jerks, make them live on Jerk Island.
55: Make sure Jerk Island isn’t actually an awesome place to live.
70: Transform Lake Michigan into biggest ball pit. Cover dead fish with plastic balls.
115: More eyepatches.
262: Regulate burps.

I think you get the idea. As Tears for Fears almost said, everybody wants to change the world.

And we do change it. We change it in a huge way. Cumulatively, the tremendous force of the human race has drastically altered the face of the planet, from oceans to atmosphere. But a lot of that change is sort of accidental; we don’t mean to affect the acidity of the oceans or warm the atmosphere, but we like driving around, making things, using electricity, and all that, and the byproducts of these activities have global effects that we can’t always control.

The notion that we could control these effects is called geoengineering. So we’re accidentally causing global warming … what if we could engineer a global solution to actively cool the planet. We’re causing ocean acidification … what if we could chemically alter the oceans on purpose to balance it out? The trick would be to balance out the positive effects of geoengineering with the potential side effects … if we could even figure out what those side effects are.

Geoengineering is necessarily a really large-scale thing, so for the most part it’s been limited to theoretical projects. But it’s been pointed out that some geoengineering projects would be within the capabilities of not just international bodies or individual countries, but corporations or even wealthy individuals. The Science Museum of Minnesota even has an exhibit on just this possibility: What would you do if you had the wealth to literally change the world?

But there are rules against that sort of thing, and it’s potentially really, really dangerous. So no one would actually do it in the real world ever, right?

Wrong!

Apparently someone did do it. Back in July.

A guy named Russ George, in partnership with a First Nations village, is thought to have dumped about 100,000 kilograms of iron sulfate into the ocean off the Western Coast of Canada. Why iron sulfate? Because iron sulfate is an effective fertilizer for plankton, the microscopic plant-like things in the ocean. The idea is that if you could cause massive growth in plankton, the plankton would suck up a bunch of carbon dioxide from the atmosphere before dying and falling the ocean floor, taking the CO2 with it.

The first part of the plan seems to have worked: satellites have detected an artificial plankton bloom about 6,200 square miles large off the west coast of Canada (which is how the operation was discovered).

George was hoping to make money selling carbon credits gained from the CO2 captured by the plankton, and he convinced the First Nations group involved to put about a million dollars into the project, telling them that it was meant to help bolster the area’s salmon population.

The thing is, it’s really hard to say what dumping almost half a million pounds of iron sulfate into the ocean will do, besides capture some CO2. And, what’s more, it looks like it was illegal: conducted as it was, the operation violates the UN’s Convention on Biological Diversity and the London convention on dumping wastes at sea. Whoops.

So does this spell the end for individually funded geoengineering projects? Or has George’s scheme just opened the door for similar operations?

And, more importantly, is this a good thing or a bad thing? Are people like George taking big steps toward addressing human-caused global change? Or are they creating what I like to call “Pandora’s Frankenstein*”?

Weigh in in the comments, and let us know what you think!

(*My friend Pandora has a pet chinchilla named Frankenstein, and he is horrible. I can’t wait until that chinchilla dies.)

Mar
20
2010

Dino killer
Dino killerCourtesy Donald Davis (for NASA)

How Earth impact kills dinos

As "mdr" explained recently in, astroid found guilty of killing dinosaurs that a panel of scientists, after reviewing all evidence, blame an asteroid impact for the demise of the dinosaurs.

Ozone killed the dinosaurs

A paper has just been published saying that dinosaurs choked on ozone.

A new study in the journal Paleogeography, Paleoclimatology, Paleoecology puts forth the idea that the Chicxulub impact, long blamed for the extinction of the dinosaurs at the end of the Cretaceous era 65 million years ago, could have done them in by flinging huge amounts of ozone precursor chemicals -- nitrogen oxides, methane, and other hydrocarbons -- into the air.

Below the article in Discovery News, this comment by 1sang (Doug) explains why mammals and avians survived.

In order to (survive) all you'd have to do is get on steeper slopes and find enough food to live for a couple of years. Mammals and smaller avian dinosaurs could more easily accomplish this than their massive cousins (in fact, many were probably already in this safety zone away from the many large predators roaming the lowlands).

He also notes that methane release leads to an increase in ozone and that today we have the beginnings of lots of methane being released (I wrote about this here: Methane ice).

Mar
06
2010

Chilean quake sped up Earth's rotation, tipped planet's axis

Earth spins faster
Earth spins fasterCourtesy NASA
If you read the post about how earthquakes differ, you would know that in the Chile earthquake, a large amount of the Earth's crust plunged under its neighboring crust, bringing it closer to the center of the earth.
Just as Olympic figure skaters spin faster when their arms move closer to their body, the Earth is now spinning faster making our day about 1.26 microseconds shorter than it was before the quake.
Earth was also slightly tipped off balance, like when a spinning skater brings in one arm but not the other. The planet's axis tilted about 8 centimeters. This is insignificant compared to other wobbles measuring several meters resulting from winds and ocean currents.

Alfred Wegener birthday

by Anonymous on Nov. 01st, 2009


Alfred Wegener: Greenland, 1930.Courtesy Public domain
Today is the birthday of Alfred Lothar Wegener, the scientist who first developed the theory of continental drift. Wegener was born in 1880, schooled as an astronomer, and became interested in climatology and meteorology. When he noticed how the shapes of some continents fit nicely into the forms of others, (such as how South America fit into Africa), he proposed in 1915 that they had once all made up a supercontinent he called Pangaea, and later drifted apart. Similar rock strata and fossils found in coastlines of distant continents seemed to corroborate his theory, but Wegener was unable to come up with a mechanism that would cause such movement, so his theory lay dormant, mostly spurned and unaccepted until the 1950's when new geological evidence regarding plate subduction and sea-floor spreading came to light. Wegener's theory of continental drift is the basis for present-day theory of plate tectonics. Unfortunately, Wegener didn't live to see his theory gain acceptance. He died tragically sometime in late 1930 while on a meteorological expedition to Greenland.

More about Alfred Wegener

Mar
27
2009

Ever wonder just why the Red River seems to flood so regularly? North Dakota State geology professor Don Schwert says:

"Fargo and Moorhead sit on one of the flattest surfaces on Earth. It's the lakebed of what was a gigantic lake at one time--glacial Lake Agassiz. Lake Agassiz was here from about 12,000 years ago to about 9,000 years ago, and after the lake drained, it left behind sediments that formed this flat surface. These sediments form the basis for wonderful soils, but they form as well this flat surface off of which water is reluctant to drain. And so the Red River is doing the best it can in trying to process water across this flat landscape. But what happens is that, during times of floods, as we're having now, water spills out of the channel and onto the bed of the old glacial lake, and the glacial lake sort of reappears."

"The Red River Valley is unusual compared to other river valleys around the world. Most river valleys are effectively carved by the rivers themselves (if you think about the Colorado River, or the Mississippi River). But the Red River Valley, the river itself couldn't have begun to flow until glacial Lake Agassiz drained about 9,000 years ago. Now the importance of that statement is that we normally measure the ages of rivers around the world in terms of hundreds of thousands of years, millions of years, maybe even tens of millions of years, and here we have a river that began to flow about 9,000 years ago, and began to flow across this flat surface. It hasn't had time and it hasn't had the energy to carve any kind of meaningful valley. The lakebed of Lake Agassiz becomes the effective floodplain in times of flooding, and the river spills out onto the old lakebed, and glacial Lake Agassiz kind of reappears."

"One of the problems with the Red River is that floods can't be confined, in an engineering sense, by means of dams. A dam crosses a river valley, and water builds up behind it, and it can store water. Well, here we have this expansive surface: the feature we call the Red River Valley is actually the lakebed of Lake Agassiz, and in some places it's 60 or 70 miles wide, and there's no way, really, of effectively managing water in terms of reservoir storage in the southern Red River Valley.... There's really no other river in the world like it."

"[The Red River flows north, which is not really unusual.] But it does have a consequence: typically, in the Red River Valley, a spring thaw begins in the southern portion of the valley. So waters are released in the southern portion of the valley and begin slowly to work their way northward at about the same pace, perhaps, as the the thaw is working its way northward along the valley. So as waters are being delivered northward, waters are also being released in portions of the valley. And everything's kind of clumping together and keeps on building up as the river and its waters and the flood are processed northward. So it becomes very problematic, particularly in the northern portion of the valley: massive, shallow, expansive floods. In 1997, in portions just north of the North Dakota border on into Manitoba, one could measure the flood, in terms of width, at 60 to 70 miles wide. An Ohio River flood might be 1,000 yards. Here it's 60 to 70 miles wide, so it's an incredibly expansive flood. It's sort of a rebuilding of the old lake, in that sense."

"Urban development, or urbanization, is a problem worldwide in terms of helping to exacerbate flooding of rivers. If we think about the path of a raindrop before human settlement, that raindrop would take a long time being delivered into the main drainage. But here in Fargo-Moorhead, or cities elsewhere around the world, we can process that raindrop in a matter of minutes or a couple hours in there, and it's immediately delivered into the channel. When we think about parking lots and shopping malls, housing and driveways and streets, highly efficient drainage ditches or drain tiles in agricultural fields--all of that is processing water, all of that is accelerating the delivery of water into the main stem drainages."

(You can listen for yourself at the link above.)

Glacial Lake Agassiz and the Red River Valley: Not all of this huge area was underwater at one time, but Lake Agassiz was bigger than all the Great Lakes put together and held more water than all the lakes in the world today.
Glacial Lake Agassiz and the Red River Valley: Not all of this huge area was underwater at one time, but Lake Agassiz was bigger than all the Great Lakes put together and held more water than all the lakes in the world today.Courtesy Figure 1-2 from A River Runs North, by Gene Krenz and Jay Leitch, Red River Water Resources Council (1993)

Lake Agassiz
Lake AgassizCourtesy North Dakota Geologic Survey

More interesting resources:

Minnesota Public Radio posted this cool time-lapse, shot over 20 minutes, of sandbag operations at the Fargodome on Wednesday, 3/25.

One more interesting/worrisome thing to consider: the area of Canada once covered by the glaciers and glacial Lake Agassiz is still slowly rebounding after being pressed down by the weight of the ice. According to the New York Times,

"For the north-flowing Red River, that means its downhill slope, already barely perceptible, is getting even less pronounced with each passing year, adding to its complexity, and its propensity to flood."