Monthly Archives: January 2011

Finding other “Earths”

“Within the next 6 to 12 months, I suspect we’ll be able to detect and verify and announce planets that at least have the size of our own Earth.”

–Dr. Geoffrey Marcy, University of California Berkeley

“This changes our understanding of our role in the universe. We, in some sense, are not alone in terms of being a planet circulating around a star. We now realize, that potentially, there could be thousands, billions of planets right in our own back yard, right in our own Milky Way galaxy. This is a game changer.”

–Dr. Michio Kaku

The recent news release about Kepler-10b has put NASA into the spotlight again.

Click on the link below to watch a really great video from The Wall Street Journal about astronomers’ latest discoveries of new planets and how they’ll know if they’ve found a planet that can support life.

The Search for Other Earths

The most intriguing news… NASA scientists have sequestered data from 400 stars. Does this mean that they’ve already discovered another “Earth?” Stay tuned…

Read the associated print article: “Planet Data to Fuel Hunt for Life.”

Slow down glacial flow with warmer summers?

It seems counter-intuitive, but it seems that warmer summers actually slow the flow of Greenland’s ice sheets.
A new study, published yesterday in Nature, explains how increased melting in warmer years causes the internal drainage system of the ice sheet to change, slowing the glacier’s flow towards the ocean.
Normally, the melt-water finds its way to the bottom of the ice sheet, acting as a lubricant that helps the glacier to flow towards the ocean.  With less melt-water below the glacier, its flow is impeded, so it doesn’t recede as quickly.
So, are hot summers the cure to glacial melting?  Obviously not.
Warmer temperatures do cause more melting.  Although the glaciers aren’t moving towards the ocean faster, they are melting from the surface downwards.  The big difference is in the plumbing–whether the melt-water is trapped under the glacier, lubricating its path to the sea, or whether the melt-water is drained away through a different plumbing system.  The ice will still melt.
This surprising data just shows that more research is needed to fully understand how glaciers are affected by changing temperatures.  Dr. Edward Hanna, one of the co-authors, underscored the importance of using models in studying the relationship between glacial melt and climate change:
“This work also underlines the usefulness of modern gridded climate datasets and melt-model simulations for exploring seasonal and year-to-year variations in Greenland ice sheet dynamics and their relationship with the global climate system.”
Explore the relationship between temperature and ice-melting in our activity, “What will Earth’s climate be in the future?

It’s going to be a warm one in the south…

Warm millennium, that is.  And Southern Hemisphere, that is.

New research suggests that Earth will continue to warm into the year 3000, even if human-caused carbon dioxide emissions stop right now.  According to their models, scientists predict that the Northern Hemisphere will fare much better, with the warming trend reversing within the millennium.  This is likely due to the much larger landmass in the Northern Hemisphere.

The Southern Hemisphere has much more ocean surface, which has thus far slowed the warming trend, as the ocean acts as a huge carbon dioxide and heat sink.

Shawn Marshall, Canada Research Chair in Climate Change and University of Calgary geography professor, explains this phenomenon:

“The global ocean and parts of the Southern Hemisphere have much more inertia, such that change occurs more slowly. The inertia in intermediate and deep ocean currents driving into the Southern Atlantic means those oceans are only now beginning to warm as a result of CO2 emissions from the last century. The simulation showed that warming will continue rather than stop or reverse on the 1000-year time scale.”

Does this mean certain doom for the planet?  No.  Throughout its history, Earth has had warmer periods than the one that is predicted by these models.  The Earth will be just fine.  The big question, for us humans, is how humans will fare.

Explore the role of oceans in Earth’s climate with our activity, “What will Earth’s climate be in the future?

Know thy star to know its planets

NASA scientists have deduced that the newly-discovered planet Kepler-10b is 4.6 times more massive than Earth with an average density of 8.8 grams per cubic centimeter, about the same density as bronze. How did they learn this from a telescope that detects light changes?  (See earlier post about Kepler-10b’s discovery.)

It turns out that knowing a lot about the star helps to learn a lot about its orbiting planets. Scientists had previously studied Kepler-10 in great detail, using starquakes (much like earthquakes on Earth) to learn about the interior structure of Kepler-10. Having this information made it possible to calculate the mass and density of its orbiting planet.

Finding new planets is very exciting, but it’s far more exciting to be able to infer what those planets are like. It might not be as exciting to do the basic research to characterize stars as it is to find planets, but it’s necessary to know about the stars to fully describe the planets. Just as in all scientific fields, the latest breakthrough discoveries are always built on a strong foundation of basic research.

Why do metals feel colder? An infrared view

Metals feel colder because they conduct heat faster, not because they are really "colder." This is often a misconception from students. A very simple IR experiment may dispel this misconception by visualizing what is going on when you touch a piece of metal and a piece of paper.

Lay a piece of aluminum on a foamcore board. Then cover it up with a piece of paper. Put one hand on top of the part of paper above the metal and the other on top of a part of paper that is not above the metal. Have your partner look at the hands on the plate through an IR camera. The reason that we want to cover the metal up with a piece of paper is because we want to make sure that the difference of temperature we observe has nothing to do with the difference of emissivity--the ability of a substance to emit infrared light--between metal and the base material.

The first IR image shows the initial temperature distribution when the hands were on. The second one shows the temperature distribution after two minutes. It clearly shows that the hand above the metal strip is losing more thermal energy than the hand above paper.

This simple experiment, once again, demonstrates the transformative power of IR imaging. IR imaging experiments such as this are much easier to do than conventional experiments. They provide more intuitive, richer results in a snap. Imagine how many other experiments out there that can be transformed by this new instrument!

Finding little planets with new technology

On January 10, 2011, NASA confirmed that the Kepler space telescope had found its first rocky planet, named Kepler-10b. Kepler-10b is really small, the smallest planet yet discovered outside of our solar system, at 1.4 times the size of Earth.

The discovery of Kepler-10b was made possible by some major advances in technology:

  • the ability to put the Kepler telescope into space
  • an ultra-precise photometer on the Kepler telescope that allows it to measure tiny decreases in stars’ brightnesses
  • the huge analytical power of computers needed to decipher the signal from the noise

Although Kepler-10b isn’t in the habitable zone of its star, Kepler-10, it does show us the power of technology to find more small planets, some of which may be more Earth-like and have the ability to support life.

You can explore the transit method–how the Kepler telescope detects planets–in our space investigation “Is there life outside of Earth?

How can you tell what’s in the atmosphere of a planet that’s over one billion miles from Earth?

Use a VERY long sampling straw?  Nope.
Use a spectrometer? Yup.  (Explore how this works in our “Is there life outside of Earth?” investigation.)
Scientists at NASA, the European Space Agency, and the Italian Space Agency collaborated to send the Cassini spacecraft to Saturn to get closer looks at the planet, its rings, and its many moons.  In November 2010, the exciting news came back that oxygen was discovered in the atmosphere of Rhea, one of the moons.
It took five years of measurements and data analysis to collect enough data to fully support the discovery.
So if there’s oxygen, there’s life, right?  Nope.  There are lots of organisms on Earth that don’t need oxygen.  And Rhea is too far from the Sun to be in a “habitable zone” anyways.
This discovery, relatively close to home, shows that we can detect molecules in the atmosphere of an orbiting body nearly one billion miles away.
And if we can make the measurement from that far away, it’s only a matter of time until we’ll be able to measure atmospheres of planets and moons outside of our solar system!

Finding a needle in a haystack–how to deal with noise in the data?

Scientists have used indirect measurements of movement to infer the presence of waves for a very long time.  For example, how can you tell when it’s windy without going outside?  You look to see the movements of the trees or flags or other flexible structures.

Now, scientists at NASA’s Jet Propulsion Laboratory are using lasers to measure gravitational waves.  Gravitational waves were predicted by Albert Einstein, but only in the last few years has the equipment gotten sensitive enough to attempt measurements.  The scientists face the task of detecting a wave that’s 0.000000000005 meters tall from spacecraft 5,000,000,000 meters away!
Using known masses attached to spacecrafts and lasers that measure the positions of the masses, the scientists hope to detect the movements caused by gravitational waves.  Lasers, although very precise, are still too noisy to measure the gravitational waves.  (Learn more about noise and using indirect measurements in our “Is there life outside of Earth?” investigation.)
What’s the solution to the noise problem, finding that tiny little wave across trillions of miles?  Generate artificial noise in the lab and see if you can still detect the signal.  It’s worked in the laboratory, so scientists may soon be able to detect gravitational waves in space.
The ability to detect smaller and smaller motions will enhance the ability of instruments to detect smaller and smaller planets around other stars–perhaps even another “Earth.”  Technological innovation is the only limit.

Missing: Fresh Groundwater

Where has all the groundwater gone, long time passing? (My apologies to Pete Seeger and Joe Hickerson.)
It’s gone into the sea.
Scientists in the Netherlands have made the shocking discovery that much of the water pumped out of the ground evaporates and ends up in the oceans.  Amazingly, this raises the sea level by 0.8 millimeters per year.  That doesn’t sound like a lot, but to put it in perspective, that’s roughly the same amount of sea level rise caused by melting glaciers and icecaps outside of Greenland and Antarctica and 25% of the total sea level rise per year!

How much does a star weigh?

Scientists may soon find out.
Orbiting objects exert a gravitational pull on each other.   This gravitational pull is what gives objects their weights; it’s the reason that you weigh 83% less on Earth’s moon than on Earth, without losing any of your mass.
Scientists are currently using measurements of objects’ gravitational pulls to find new planets around stars.  As a planet orbits around a star, it pulls on the star, making the star appear to wobble.  Looking for the wobble (as you can do in our space investigation”Is there life outside of Earth?“) is how scientists find objects around stars.
David Kipping, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics, realized that by using the same strategy with a planet and its orbiting moon, along with some calculation using Kepler’s Laws of Motion, scientists will be able to determine the mass of distant stars.
In essence, they’re just measuring the wobble effect that all three objects (star, planet, and moon) exert on each other.  All they need to do now is find stars that have planets that have at least one moon.
“When they’re found, we’ll be ready to weigh them,” said Kipping.