Stories tagged earth
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.
Tags : 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.
Australian scientists studying albedo--the amount of sunlight reflected off the Earth—have created a flat cardboard kangaroo 105 feet tall. Photographing the image from space will give clues to how the Earth’s atmosphere heats up and cools down.
NASA Science website is an awesome resource
NASA Science website
Courtesy NASA To show how useful this site can be, here are links to pages I found as I dug deeper into just one of the many areas on the NASA Science website.
Science for different levels of learning
The NASA Science website provides learning opportunities for four learning groups.
Earth, sun, planets, and astrophysics
The NASA Science website is divided into these parts.
Al & the Earth: I wonder if Al Gore runs a distributed computing program on his Mac when he gives his global warming talks. Probably not. Image courtesy alexdecarvalho via Creative Commons/Flickr.If you like science and you listen to podcasts I recommend Scientific American’s 60 Second Science. I don’t listen to them every day, but I store them up then listen to a bunch in a row while I am doing something menial. Today I listened to a bunch walking from my cube to the loading dock. It is a looooog walk.
Besides mentioning the giant Mars hoax emails, which I guess are circulating again with new dates, there were two stories caught my interest.
The first was about distributed computing. While I am an advocate for turning off computers at night to save energy, if you’re going to leave them on, you should put them to good use. They can either run scans on themselves, or, through distributed computing, they can use their processing power to solve large problems. One new distributed computing application that they mentioned that I found interesting is Cosmology@Home. Cosmology@Home uses your computer’s spare processing power to “search for the model that best describes our Universe and to find the range of models that agree with the available astronomical and particle physics data” (from their website). Since I can barely wrap my mind around the implications of that question I am glad that my computer can help find some answers.
Another interesting podcast was about global warming. Researchers from the University of Washington have been working on equations that will help get the most out of climate models. The result of their work is that while the Earth is going to get warmer, how much warmer is not known. Scientists have theorized that if the amount of carbon dioxide (CO2)in the atmosphere doubles the temperature would rise by about 2.2 degrees Fahrenheit. But, that rise in temperature does not account for the sort of “compound interest” that would take place – if the Earth warmed up because of more CO2, would the warmer atmosphere hold more water vapor? Would that increased amount of water vapor, serving as a “greenhouse gas” create even warmer temperatures? And what effect would these even warmer temperatures have on the climate models? This new equation helps scientists see the most probable scenarios more quickly than before, but also shows possible warmer results than previous models. The problem is that all this “compounding interest” makes it impossible to determine with any accuracy the high end possibilities. More on this can be found here, here and here.
Red alert: Based on what they've seen at the star V 391, astronomers say there is a possibility that Earth could survive a red giant phase expansion of our Sun. (Photo courtesy of NASA)Not that any of us reading this have to really worry about this personally, but there’s new evidence that the Earth could be able to survive should our Sun start to balloon into a red giant. That’s estimated to happen in a few billion years.
Astronomers have found a planet in a similar position as Earth’s relative to its star that continues to exist as the star has become a red giant. The star in question, V 391, was much like our Sun, but as it aged, its core ran out of hydrogen. That triggered a reaction where it began to burn helium and its outer surface expanded out about 100 times wider. It’s believed the same thing will happen to our Sun in about 5 billion years.
The planet in question has about three times the mass of Jupiter and orbits V 391 at about the same distance as Mars is from our Sun. However, the red giant action of V 391 is considered highly unusual and may be just representative of 2 percent of the red giant actions that happen to stars. Astronomers are continuing to watch what’s happening there, but say that it’s too small of a data sample to project what will happen to Earth when the Sun go to a red giant phase. The common thinking is Mercury and Venus will be vaporized in a red giant transition of the Sun while Earth would be on the borderline of the safety zone.
Best title for a science article, ever! All about efforts to track asteroids, comets and other outer space stuff that might hit the Earth, and to deflect or destroy it before it does.
The Earth as it actually is: Here we see a revised map of the planet earth. (Image by FuLL MoON on Flickr.com)Well… Maybe the home planet isn’t shrinking, exactly, but it’s slightly smaller than we used to think. So it’s kind of like it’s shrinking in our heads, which is just as bad, according to The Matrix.
Using a procedure called “Very Long Baseline Interferometry,” or just VBLI, scientists have been able to reevaluate previous estimates on the earth’s exact size. VBLI works by using a network of over 70 radio telescopes around the world to measure radio waves emitted by sources deep in space, like Quasars. Because each telescope is always going to be slightly closer or further away from the source of the radio waves, the signals are received with a slight time lag from telescope to telescope. By measuring that lag, scientists can tell the exact distances from each telescope to the Quasar, and then the distances between two telescopes “to the preciseness of two millimeters per 1,000 kilometers.” Through all this, they have discovered that the Earth is just slightly smaller than we used to think - just a matter of millimeters, though.
But what does a matter of millimeters mean on a global scale? The implications, I think, will startle you. For instance, the state of Rhode Island no longer exists. And Delaware is just a beach now. My bedroom, formerly a palatial 12’ by 13’ 6” is now a claustrophobic 11’ 11” by 13’ 5.9”. I had to throw some books out. It’s a scary world we live in, so dominated by concepts.
The Geodesists who have developed this world-measuring process are hopeful, however, that it will have the potential to make up for its grim introduction. By measuring the Earth’s size so exactly, VLBI will allow us to measure minute changes in sea level and track the progression of global warming, or to follow the exact movement of the tectonic plates (It turns out that the Swiss and us are moving 18 millimeters away from each other every year. I’m not sure how I feel about this.)
Recent comments
Which presidential candidate do you think will better advocate for the interests of science and technology?
Immaculate conception observed. In a shark.
Beware of boxelder bugs
Immaculate conception observed. In a shark.
Subscribe
I want to learn about
Science Buzz and all related activities
Science Museum of Minnesota, 2004-2008,
except where otherwise noted.
Copyright Information
Add a new comment