A view of the Earth from space. What shape does it look like to you?
Click on image for full size
Image courtesy of NASA/JPL

The Equator is Growing!
News story originally written on August 7, 2002

Earth may look perfectly spherical from space, like a giant marble, but it actually isn't! Instead, our planet is wider around the equator because matter is forced out as Earth spins (just as you feel you are pushed right when your car turns fast to the left). The Earth does not stay the same shape however, and scientists have been watching Earth's equator as it shrinks and grows!

Standing on Earth's surface, we cannot see the small changes in Earth's shape but researchers have been watching the equator grow smaller with satellites over the past 20 years or so, and they believe this has been happening since the last ice age 18,000 years ago. Since the ice age, temperatures warmed and glaciers at the poles melted slowly. Little by little the poles became less squashed under heavy ice. Molten rock moved under the Earth's crust from the equator to the poles to fill in the new space and the equator grew smaller.

For the past four years, however, Earth has been doing something quite different. Researchers have found that the equator is now growing larger! Since we know that glaciers are still melting at the poles, scientists are puzzled why the process would change.

For Earth's equator to increase in size, material must have been moved there from somewhere else on the planet. One hypothesis is that molten rock has been moving deep within the Earth from below the poles to below the equator because of small changes in Earth's magnetic field. Another hypothesis is that there is more water at the equator as melting glaciers add more water into the oceans, which moves towards the equator with currents.

Whatever the reason, the researchers believe that this change in the shape of Earth is natural variation, not anything that humans have done to the planet.

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

The Earth's Magnetic Field

The Earth has a magnetic field with north and south poles. The Earth's magnetic field reaches 36,000 miles into space. The magnetic field of the Earth is surrounded in a region called the magnetosphere....more

1999--A Year in Review...

It was another exciting and frustrating year for the space science program. It seemed that every step forward led to one backwards. Either way, NASA led the way to a great century of discovery. Unfortunately,...more

STS-95 Launch: "Let the wings of Discovery lift us on to the future."

The Space Shuttle Discovery lifted off from Kennedy Space Center on October 29th at 2:19 p.m. EST. The weather was great as Discovery took 8 1/2 minutes to reach orbit. This was the United States' 123rd...more

Moon Found Orbiting Asteroid

A moon was discovered orbiting the asteroid, Eugenia. This is only the second time in history that a satellite has been seen circling an asteroid. A special mirror allowed scientists to find the moon...more

U.S. is Fed Up with Russia

Will Russia ever put the service module for the International Space Station in space? NASA officials want an answer from the Russian government. The necessary service module is currently waiting to be...more

More on Recent Coronal Mass Ejection

A coronal mass ejection (CME) happened on the Sun early last month. The material that was thrown out from this explosion passed the ACE spacecraft. The SWICS instrument on ACE has produced a new and very...more

Mother Nature's Air Conditioning

J.S. Maini of the Canadian Forest Service called forests the "heart and lungs of the world." This is because forests filter air and water pollution, absorb carbon dioxide, release oxygen, and maintain...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA