Current Events

  • Irish Chronicles Document Links Between Volcanoes and Weather
    A study of over 40,000 written entries in Irish Annals and ice core measurements shows a strong corr...Read more

    x

    Irish Chronicles Document Links Between Volcanoes and Weather

    A study of over 40,000 written entries in Irish Annals and ice core measurements shows a strong correlation between the occurrence of volcanic eruptions and extreme cold weather in Ireland over a 1200 year period. Data analyzed in this study cover the period from 431 to 1649, during which time up to 48 volcanic eruptions are identified in Greenland ice core records through deposition of volcanic sulfate in annual layers of ice. You can find the study (open access), published on 6 June 2013 in IOP Publishing's journal Environmental Research Letters, at http://iopscience.iop.org/1748-9326/8/2/024035/article. Find out more about how volcanoes can influence climate.
  • EF-5 Tornado in El Reno, Oklahoma Widest Ever Recorded in US
    The EF-5 tornado that hit El Reno, Oklahoma on May 31st was the widest ever recorded in the US, acco...Read more

    x

    EF-5 Tornado in El Reno, Oklahoma Widest Ever Recorded in US

    The EF-5 tornado that hit El Reno, Oklahoma on May 31st was the widest ever recorded in the US, according to the National Weather Service in Norman Oklahoma. The tornado, which remained on the ground for 40 minutes and reached 2.6 miles across (4.2 km), took the lives of 18 people including storm chasers Tim Samaras, Paul Samaras and Carl Young. For more information on the tornado, visit http://ow.ly/i/2hfDG.
  • Atmospheric CO2 Level Tops 400 ppm
    During the week of May 13th, the CO2 level at the Mauna Loa Observatory in Hawaii topped 400 ppm rep...Read more

    x

    Atmospheric CO2 Level Tops 400 ppm

    During the week of May 13th, the CO2 level at the Mauna Loa Observatory in Hawaii topped 400 ppm repeatedly. Daily levels of CO2 can vary due to weather, and there are seasonal trends as well. The level of atmospheric greenhouse gases continues to increase, now over 120 ppm since the Industrial Revolution began. For more on the Keeling Curve, see http://keelingcurve.ucsd.edu/. Find out more about greenhouse gases and warming.
This picture shows the surface of Phoebe. There are many large craters on Phoebe's surface. The picture was taken by the Cassini spacecraft in 2004.
Click on image for full size
Image courtesy of NASA/JPL/Space Science Institute.

Phoebe

Phoebe is the name of a medium-sized moon of Saturn. An American astronomer named William Henry Pickering discovered Phoebe in 1898. The name "Phoebe" comes from Greek mythology. In the Greek myths, Phoebe was the daughter of Uranus and Gaia and the grandmother of Apollo and Artemis.

Phoebe has a diameter of 220 km (137 miles). It is the ninth largest of Saturn's moons. The surface of Phoebe is very dark. That is strange. Most of Saturn's moons have bright surfaces. Its dark surface isn't the only strange thing about Phoebe.

Phoebe's orbit around Saturn is also odd. Phoebe orbits much further from Saturn than any of the other medium-sized moons. Also, Phoebe orbits backwards! It moves around Saturn in the opposite direction of most of the other moons.

Why is Phoebe so strange? Many astronomers think Phoebe used to be an asteroid or Kuiper Belt Object. They think Saturn's strong gravity captured Phoebe sometime long ago.

Astronomers want to learn more about Phoebe. Right now, our only pictures of Phoebe are very fuzzy. They were made by Voyager 2 in 1981. Soon we should have much better pictures! The Cassini spacecraft will fly very close past Phoebe on June 11, 2004.

Last modified October 8, 2009 by Randy Russell.

Shop Windows to the Universe Science Store!

Our online store includes issues of NESTA's quarterly journal, The Earth Scientist, full of classroom activities on different topics in Earth and space science, as well as books on science education!

Windows to the Universe Community

News

Opportunities

You might also be interested in:

Traveling Nitrogen Classroom Activity Kit

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

Apollo

In Greek mythology, Apollo was the son of Zeus (Jupiter) and Leto (Letona). He was the twin brother of the goddess Artemis. He was the god of the Sun, logic, and reason, and was also a fine musician and...more

Medium-sized Moons of Saturn

Saturn has // Call the moon count function defined in the document head print_moon_count('saturn'); moons. Many of those are tiny chunks of rock or ice only a few kilometers (miles) across. One of Saturn's...more

Voyager

The rare arrangement of planets Jupiter, Saturn, Uranus, and Neptune in the 1980's made it possible for the Voyager spacecrafts to visit them over a 12 year span instead of the normal 30. They used gravity...more

Cassini

A spacecraft named Cassini will study the planet Saturn for several years. Cassini blasted off from Earth in October 1997. After flying past Venus, Earth, and Jupiter, Cassini finally arrived at Saturn...more

Cassini approaches Saturn's Moon Phoebe

The Cassini spacecraft is on its way to Saturn. It will zoom close past a strange moon of Saturn named Phoebe. Cassini's close flyby of Phoebe will be on June 11, 2004. The best pictures we have right...more

The Phoebe Ring Around Saturn

The Phoebe Ring is one of the rings around the planet Saturn. The Phoebe Ring is much bigger than Saturn's other rings. It is about 100 times larger than the main ring system. Saturn's moon Phoebe orbits...more

Saturn's Rings

Many people like Saturn's rings. Although Saturn isn't the only planet with rings, it is the only planet famous for them. Almost every image or drawing of the planet has the rings included. But few people...more

Shop Windows to the Universe

Our Glaciers: Then and Now activity kit helps you see the changes taking place in glaciers around the world. See all our activity kits and classroom activities.

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part by the National Science Foundation and NASA, our Founding Partners (the American Geophysical Union and American Geosciences Institute) as well as through Institutional, Contributing, and Affiliate Partners, individual memberships and generous donors. Thank you for your support! NASA AGU AGI NSF