November 29, 2011

For today’s Cool Photo of the Week, Seymour Simon chose this photograph taken by NASA’s Mars Reconnaissance Orbiter, an unmanned satellite that has been orbiting the Red Planet since 2005. The orbiter is searching for evidence that water was once present on the surface of Mars. NASA scientists also want to know whether water was present long enough to support life at some time in the past. 

Look at the deep ditches and trails criss-crossing the sand dunes in an area of Mars known as the Russell Crater. These trails were carved into the landscape by "dust devils," mini-tornadoes that whip across the Martian landscape. The ditches are formed when chunks of frozen carbon dioxide slide down the face of steep dunes.

When I speak at schools, I often tell students about an astronomer named Percival Lowell, who thought he spotted Martian "canals" through his small telescope back in the early 1900s. Do you think it’s possible that he saw these deep trails, leading him to the mistaken idea that the canals must have been dug by intelligent life, or Martians?!

September 20, 2011

Today’s Cool Photo of the Week is a detailed image of Saturn’s rings, captured by the Hubble Telescope, using ultraviolet light. The rings are made up of many small particles of ice, with some dust and small bits of rock, that have formed into clumps and orbit around Saturn. Some of the particles are as small as your fingernail; others are bigger than a car! Seen from afar, they blend together and appear to be rings around the giant planet. 

Saturn is the second biggest planet in our solar system, after Jupiter. How big is Saturn? About 75 Earths could fit inside of Saturn. Although it is not the only planet with rings (Uranus and Neptune have rings, too), Saturn’s rings are the largest and most visible.  

This image of Saturn was taken when the planet’s rings were at their maximum tilt of 27 degrees toward us. Saturn experiences seasonal tilts away from and toward the sun, much the same way Earth does, over the course of its 29.5-year orbit. That means that every 30 years, we Earth observers can catch our best glimpse of Saturn’s south pole and the southern side of the planet’s rings. 

Isn’t this a magnificent image of Saturn?

Photo: NASA and E. Karkoschka (University of Arizona)

July 12, 2011

Can you imagine a single hurricane that has lasted for centuries? In this activity (click here to download), you will learn more about a giant storm on Jupiter that has not changed its position for hundreds of years. 

 Every week from now until Labor Day, we will publish a new nature project. The goal is to get kids outdoors, exploring and enjoying the world around them. Check back here every Monday for a new installment of Summer Vacation Science.

May 10, 2011

Set your alarm for just before dawn tomorrow morning, May 11 and you can see FOUR of the planets in our Solar System with your own eyes!

Mariano Ribas took this photo early today from his home in Buenos Aires, Argentina. The three "stars" that form a triangle high in the sky are Venus, Mercury and Jupiter. If you look down below, closer to the fence, there is a fourth faint light, which is Mars. 

This amazing sky show will continue all the way through the end of the month. Astronomers are excited about tomorrow because they say it will be the "best" day for viewing, with the two brightest planets in our Solar System, Venus and Jupiter, very close together.

Set your alarm, look to the eastern sky, and greet the planets. What a great way to start the day!

January 14, 2011

Alas, poor Pluto is no longer considered to be a planet by the scientists of the IAU (International Astronomical Union).  Astronomers use three criteria for a body to be called a planet: 1) it has to be in orbit around the Sun. 2) it has to have enough mass to pull together so that it becomes nearly round. And 3) it has to have enough mass and gravitational pull to clear out other bodies in the space around it. Pluto meets the first two tests, but it does not have enough mass to clear the space around it (for example, if it had enough mass its gravity would pull a meteorite down so it crashes to the surface). So Pluto has been renamed a Dwarf Planet. All you kids who have memorized the planets in order from the sun will now have to stop at Neptune, the eighth planet from the sun.

Here’s some more information about Pluto from Space.com, a really neat site that you can use to find out all kinds of interesting facts about what’s out there. 

September 20, 2010

I can just imagine how excited I would have been for this event when I was a young kid and a member of the Junior Astronomy Club at the American Museum of Natural History in New York City. Wait a second there, young Seymour  — I’m STILL excited about it! Here’s what’s going on this evening: Jupiter, the biggest planet in our solar system, will be overhead in the night sky at midnight, shining brighter than everything except the Moon.

Jupiter and Earth each revolve around the sun in their respective orbits. Earth takes 365 days, one Earth year, to make one revolution.  It takes Jupiter nearly 12 Earth years, 4330 Earth days, to make one revolution around the sun. That means that the two planets are rarely very near each other in their orbits. But not tonight. Earth and Jupiter are the closest together in space that they will be for the 12 years, until 2022.

If you look through even a small telescope or a pair of high-magnification binoculars you should see Jupiter’s four big moons (called the Galilean moons because of their discovery in 1610 by the great scientist Galileo).  Galileo used a small telescope that is about 20x magnification.The four moons he discovered are name Io, Europa, Ganymede and Callisto.

 Here’s a photo of Jupiter and the shadow of Io on the surface of the planet. This was taken by Anthony Wesley of Australia (he used a much higher magnification, so you won’t be able to see Jupiter quite like this).  

March 26, 2010

Hi my name is Spencer G. and I am doing a research project for school. I told my mom I wanted to interview you for my ‘Origins of the Sun’ project. I could not believe it when she told me she had gotten in touch with you and to leve my questions here for you!
1. What role did the sun play in the formation of the Milkyway?
2. What role did the planets play in the formation of the sun?
3. What role diddid the sun play in the formation of the planets?
4. What role did the stars, (other then the sun,) play in the formation of the sun?
Thanks so much for answering!

Hi Spencer! Good for you to be doing research on a project like this!

Briefly, our sun is only one tiny star in the billions of stars that make up the Milky Way Galaxy. So the question might really be the reverse: How was the sun (and all the other stars) born in the Milky Way Galaxy? Stars (like the sun) are constantly being born in spots called "star nurseries" in galaxies.

The planets were formed in a somewhat different manner and that is also rather complex. Again briefly, the planets formed from hot gases similar to the sun, but the gases cooled, other elements formed from the gases that were cooling and the planets were born. Finally, the other stars really had no role in the formation of our own sun. All the stars (including the sun) were formed in the same manner.

Hope this helps starting your research Spencer! Good luck on your project. You will be able to find more information in my books: THE SUN and OUR SOLAR SYSTEM. You should be able to find these books in your school library, or your local public library.

Good luck with your report!

July 21, 2009

Comet may have hit Jupiter - Rare Photographs

there is a a series of photographs showing a comet (named Shoemaker-Levy 9)  slamming into the surface of Jupiter in July, 1994. Fifteen years later, astronomers have photographed what may have been another comet crashing into the planet. Jupiter is the largest planet in our solar system and has a strong gravitational pull. That’s one of the reasons Jupiter has captured so many comets and moons that circle around it.  Scientists are always excited when they are able to photograph such an impact. It tells them much about the composition of the planet.

 

March 9, 2009

March 9, 2009

Are there are Earth-like planets in outer space? The Kepler mission aims to find out. We’re looking for a "Goldilocks" planet—not too hot and not too cold.

 1 2 >