Hi, Annie Richardson here, and I’m an outreach specialist with the ocean surface topography missions at NASA’s Jet Propulsion Laboratory (JPL).

Today, all around the world, people are talking about climate change and global warming. We hear about the rise of greenhouse gases in our atmosphere, about glaciers and ice sheets melting, and about global sea level getting higher and higher.

For now, let’s just talk about sea level rise. Did you know that global sea level has risen more than 3 millimeters (about one-tenth of an inch) per year since 1992? That’s a little bit more than two inches in seventeen years.

How do we know this? Well, since 1992, to measure sea surface height, NASA and the French Space Agency, CNES have been using radar altimeters on a series of satellites called Topex/Poseidon; Jason-1; and the Ocean Surface Topography Mission/Jason-2. These three satellites are the ocean surface topography missions that I‘m fortunate enough to work for.

We know that there are two things that cause sea level to rise: First, the ocean is warming, and as it warms the water expands. This is called thermal expansion and it makes the sea level higher. Second, more water is being added to the ocean because glaciers and ice sheets are melting. That melt water flows into the ocean, increasing the mass of water in the ocean and raising the sea level. The ocean surface topography missions measure all the sea level rise regardless of cause, while another satellite mission called the Gravity Recovery and Climate Experiment or “GRACE,” measures the change in mass due to new water. The difference between these two measurements tells us what part of the total rise in sea level is due to thermal expansion only.

This graph shows sea level rise as measured by the Topex/Poseidon, Jason-1, and OSTM/Jason-2 satellites from 1992-2009.

But, you might be saying, “So why the big deal about sea level rise? Two inches in 17 years doesn’t seem like very much at all.”

Well, here’s the big deal. Dr. Bill Patzert, an oceanographer at JPL, says that every inch of sea level rise will cover 50 to 100 inches of beach with water. Bill says that the actual amount of beach loss will depend on the slope of the beach, with flatter beaches being lost more quickly than steep ones.

Why is it a big deal? In less than 100 years, sea level could rise 10 or more inches, and we would lose 500 to 1000 more inches of beach. That’s 41 to 83 fewer feet of sand between your dream beach house and the surf.

Scientists are using the information from satellites not only to measure sea level rise, but to understand how the entire Earth reacts to a warming climate. Satellite observations have really helped improve our understanding of all this, but new questions arise every day, such as “How do we slow down sea level rise?” That’s where the next generation comes in. We need many more new scientists to help answer the questions about our changing planet. Who knows? It just might be your kids or your students who can protect that beach house and save the sand castles for the kids to come.

Check out this classroom activity that demonstrates how the sea-level-measuring satellites use the Global Positioning System.

Here is an explanation of El Niño, along with a yummy dessert recipe for “El Niño Pudding”.

• Topex/Poseidon, Jason-1, and OSTM/Jason-2
• The NASA GRACE website
• University of Texas GRACE website
• NASA's new Global Climate Change website
• Ocean Literacy Network site

Hi. My name is Don Neill, and I am a post doc at Caltech. I am part of the GALEX team and we all get to look at the images taken by the GALEX ultraviolet imager of faraway galaxies.

One day, I got an e-mail from my colleague, Karl Forster. When I opened the image attached to his message, several thoughts went through my mind. First, this must be some kind of artifact--an error introduced by the limits of the instrument. Second, what object is this? Third, if this isn't an artifact, this is something new. After checking the coordinates and discovering that the object in question was the venerable variable star Mira, I starting considering that this was indeed something new. What the image showed was a glowing flow of ultra-violet emission surrounding a star that was not quite bright enough, to my eye, to produce the kind of artifacts that sometimes surround the very brightest stars when their light exceeds the camera's capacity to record an image accurately. Mira is a very old, red star and should not produce that much light in the ultra-violet part of the spectrum (which scientists refer to as UV).

After several exchanges of e-mail between a few of us on the GALEX team, we gradually accepted that this glowing halo around Mira was a genuine new UV phenomenon. We agreed that we needed to trace the extent of this UV glow, which appeared to extend beyond the edge of the original image. Over the next few weeks, Karl added the required observations to the schedule. As these new images arrived, it became clear that this new feature of Mira included a long straight tail over two degrees long, or four times larger than the width of the full moon, making Mira appear like the nucleus of a comet. We began to discuss ways to explain this amazing tail on the old star.

The clues were already in the original image. Looking more closely at them, we saw that the southern edge of the feature looked like the wave that appears in front of a fast-moving boat--what physicists call a "bow-shock." Such a feature combined with the two-degree "wake" would make sense only if Mira were a fast-moving boat with respect to the thin gas between the stars of our Milky Way. So we looked up any and all measurements of Mira's motion. After accounting for the published motions of Mira and the motion of our own Sun, we found that Mira is indeed moving fast through the Milky Way "waters." More like a bullet, this shooting star is moving at well over 800 miles per second through our galaxy. This fast motion, combined with the fact that Mira is literally shedding its atmosphere, as many old stars do, produces the bow-shock and tail that had gone undetected through over 400 years of observing this well-known star.

As we wrote up our results and released our story and the new UV images of Mira to the world, I felt a deep satisfaction at having participated in a true discovery. I was not prepared, however, for the reaction to our results. People all over the world were captivated by this shooting star. We started finding our images popping up in popular science web sites in Russia, Japan and Europe. Several members of our team were interviewed on television and by numerous journalists. The National Geographic Channel based an entire episode of their show "Naked Science" around our Mira discovery. I learned from this experience that discovery leads to adventures of all kinds. I keep scanning our GALEX images hoping to have another chance to participate in the thrill of discovery and the adventures that this discovery will lead to.

The Space Place has a kid-friendly description of Mira, a "real shooting star,"

The GALEX website has lots of other amazing discoveries and images.