Dino killer
Courtesy 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).
Tags : Chilean quake sped up Earth's rotation, tipped planet's axis
Earth spins faster
Courtesy 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: Greenland, 1930.
Courtesy Public domainToday 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.
Fighting a ghost
in Earth Structure and Processes, The Water Cycle, Weather and Climate, Forces of Nature, and Historic Perspectives
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.
Courtesy Figure 1-2 from A River Runs North, by Gene Krenz and Jay Leitch, Red River Water Resources Council (1993)
Lake Agassiz
Courtesy North Dakota Geologic Survey
More interesting resources:
- Geology set the Red River on a course for flooding
- Here's a Star Tribune feature that follows the rising Red River.
- The Red River at Fargo/Moorhead is already at its highest level in history, and it's still rising. Climatologist and meteorologist Mark Seeley, National Weather Service hydrologist Mike Anderson, and MPR reporter Dan Gunderson joined Gary Eichten on Minnesota Public Radio's Midday program this morning, talking about the flood, flood history, and some lessons learned from previous disasters.
- Live feed of flood tweets on Twitter
- Flickr stream: photos of the Red River Valley flood, 2009
- In Fargo, a race against the river
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."
Each week, CNN posts a collection of space images. This week, you can see the green comet Lulin, thousands of satellites orbiting Earth, and some photos from the Hubble Space Telescope.
Oh, that?: It's just a regular centipede. But it keeps giving your trachea hungry-eyes.
Courtesy sankaxCan you believe that?
The plural of “trachea” has an “s” at the end? What. Ever.
Oh, also, some scientists think that a good place to start looking for alien life is here on Earth.
“Alien,” in this context means “different” more than it means “from another planet.” But it might also mean “from another planet.”
Does this organization makes sense to y’all? Ahh, ok, let’s go back to the beginning.
See, like, about 3.8 billion years ago the planet was a really hot, smelly, wet place. You would have hated it. Nonetheless, some self-replicating molecules ended up evolving themselves into simple little cells. The cells probably hated it there too, but lacked the capacity to do anything about it, other than continue evolving. So they did that, and evolved into more complex cells that could deal with the environment a little better. And those things evolved into multi-cellular organisms, and those things evolved… and so forth, and so forth, until the planet had scorpions, and kelp, and people, and electric eels, and streptococcus, and a bunch of other stuff. Ta-da! And we thought that if there’s anything else alive and different in the universe, it must be on a different planet somewhere, because we’ve got tabs on pretty much everything here.
Not so, says physicist Paul Davies, not so.
If life could evolve independently under very different conditions from ours on another planet… why couldn’t it evolve independently under very different conditions here on Earth? There are areas of Earth that are extremely inhospitable to “life as we know it,” but could have hosted the evolution of a different kind of life, a “second genesis.”
Davies presents the example of lakes that have extremely high levels of arsenic. There are organisms that live in those lakes, and use the arsenic for energy, but they don’t incorporate it into themselves. It’s not inconceivable, however, that a different form of life could exist there—something that uses arsenic in the same way life (as we know it) uses phosphorus.
It’s possible that “alien” life could exist in the very same environment as us, but we have never noticed it because we don’t even know what to look for. As Davies puts it, “All our microscopes are customized for life as we know it —so it's no surprise that we haven't found microbes with different biochemistry.”
Is your mind blown? Or are you still reeling from “tracheas”?
If, then, there is a different kind of life here on Earth that we could eventually observe, the question becomes, “Where did it come from?” Rocks occasionally get knocked off Mars to fall on Earth—some microscopic life could have hitched a ride. Or did it evolve here on Earth? And, if so, would it be related at all to the rest of life? Or did it evolve completely independently from us (everything else)? Ooooh, it makes you wonder.
Scientists propose a “Mission to Earth” (er… check) to explore for new life. This either has to be a meticulous examination of “the world's most inhospitable environments—deserts, salt lakes, and areas of high pressure, temperature or UV radiation,” or we have to start looking in areas we’ve already studied by painstakingly removing everything we already know about (and only those things), a process that has been used to discover new organisms in sea water.
It’s a pretty cool new way of thinking about the search for alien life (I think the word “paradigm” is hiding around here somewhere). Bummer that it doesn’t involve space ships, but I guess we can deal with that.
Um, also, just so we’re all clear, the part about aliens laying eggs in our trachea is really unlikely. It would sort of defeat the point—that’s more of a “life as we know it” sort of thing to do.
This morning when I work up, it was a clear sky, and the moon was very bright. To me, the moon this morning was the same size but definitely brighter. It was an amazing view. I'll have to post a picture of it tonight if the sky is clear. But I just read this on space.com about this morning moon sighting: http://www.space.com/spacewatch/090109-biggest-full-moon-2009.html
Did you read the last part to this article? What did you think about it?
The Earth’s magnetic field seems to be weakening in some places. This can allow high-energy particles from space to enter the atmosphere, where they can wreak havoc on electronic communications. It may also be a prelude to a flip in the Earth’s polarity, with the north and south magnetic poles switching places. Santa Claus may have to move as a result.
Gravitational compression
Will Earth ever freeze?: Internal radioactive decay is expected to keep Earth heated for billions of years.
Courtesy NASA In its beginning, the Earth was so hot that it was entirely melted. That heat was generated because of gravitational compression. As gravity pulls materials in outer space towards each other they are compressed. When atoms and molecules are squeezed together they generate heat. Matter at the earth's center is very compressed; in fact, Earth is the densest planet in the Solar system.
Gravitational sorting
Penn State professor of geosciences, Chris Marone, feels that the original heat from that molten earth is only about 5 to 10 percent of the total heat within our planet. Another source of heat is from gravitational sorting.
In a gravitational sorting process called differentiation, the denser, heavier parts were drawn to the center, and the less dense areas were displaced outwards. The friction created by this process generated considerable heat, which, like the original heat, still has not fully dissipated.
Latent heat
Another source of heat is latent heat. When material in the center of the Earth changes from a liquid to a solid, heat is released. The solidified material also expands, which increases the pressure, thereby increasing the temperature. "The inner core is becoming larger by about a centimeter every thousand years," Marone says.
Almost all Earth's heat comes from radioactive decay
Marone says, the vast majority of the heat in Earth's interior—up to 90 percent—is fueled by the decaying of radioactive isotopes like Potassium 40, Uranium 238, 235, and Thorium 232 contained within the mantle. The amount of heat caused by this radiation is almost the same as the total heat measured leaving the Earth.
Source: Penn State University Live
From time to time as I gather up the questions from the on-site Scientist on the Spot features we find some good questions that don’t connect well to the featured researcher. Here are some of those questions.
Why are stars circles?
Iapetus' equatorial ridge
Courtesy NASAI am assuming you mean, why are they round or spheres? It’s because of gravity. The larger something is (or the more mass something has) the more gravity it has. That gravity pulls equally in, so that’s why stars and planets are round, gravity makes them that way. The fancy-pants scientific name for this is isostatic adjustment.
But the Earth, for example, is not a perfect sphere – it bulges out in the middle because of its rotation. Smaller asteroids are oddly shaped because they don’t have enough mass to produce the gravity necessary to pull them into spheres. Some planets are oddly shaped too, and scientists are not sure exactly why. Saturn’s moon Iapetus is a great example. It is for some reason shaped more like a walnut and has an equatorial ridge that scientists cannot come to a conclusion as to how it formed.
What is a pimple?
Well, our skin has pores which are connected to glands that produce sebum – like an oil. Sebum is a good thing - it acts to protect and waterproof our skin, and keeps it from becoming dry. When these pores get blocked by dirt or dead skin (which we shed constantly) the secretions of sebum that would normally come from the pore are blocked and build up. These can become infected with bacteria which causes pimples to form.
The harder question is for me – to pop or not to pop. I can’t resist popping a pimple – it is a character flaw that has resulted in me sporting many a wound worse than the original zit. A great “how to pop a pimple” step-by-step is posted here.
Why do beans make us fart?
When food gets to your large intestine it is eaten by the 200+ different species of bacteria that live there and target parts of the food our stomach and small intestines can't digest, and gasses such as methane, hydrogen and hydrogen sulfide are produced as a by-product. Beans contain several sugars that we can’t digest, so lots of gas is produced by bacteria eating the otherwise indigestible material.
What is the scientific name for a pig?
What is the moon?
The big whack
Courtesy NASAYou mean besides being the only natural satellite of the Earth and the cause of the tides and so forth?
I think that the Earth collision theory (also known as the Big Whack) for the creation of the moon is the coolest, and is the one that is the most accepted today. The hypothesis goes that a Mars-sized (Mars is less than half the size of the Earth) planet collided with Earth a looooooooooong time ago and the debris that was created orbited around the damaged Earth and formed into the moon through a process called accretion – or the growth of large bodies like the moon by gravitationally attracting more matter. So the little bits of debris were attracted to bigger and bigger bits as the bigger bits had more gravity. As we learned above, the spherical shape arises from gravity as well. It is believed that as a result of the collision the smaller planet (Theia) was destroyed, ejecting its mantle into space while its core sank into Earth’s core.
Did you know that the moon is in synchronous rotation with the Earth? That means it keeps nearly the same face turned towards the Earth at all times.
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