Image description: This is Niijima, Earth’s newest island. It formed in late November as a result of volcanic activity in the Pacific “Ring of Fire.”
The island is located about 1,000 miles south of Tokyo.
Learn more about this new island.
Photo from NASA.
Image description: NASA has released a natural-color image of Saturn from space, the first in which Saturn, its moons and rings, and Earth, Venus and Mars, all are visible.
The new image was taken by NASA’s Cassini spacecraft. Learn more about it and see more views.
Photo from NASA/JPL-Caltech/SSI.
Thanks to NOAA for the answer:
While the Earth appears to be round when viewed from the vantage point of space, it is actually closer to an ellipsoid. However, even an ellipsoid does not adequately describe the Earth’s unique and ever-changing shape.
Our planet is pudgier at the equator than at the poles by about 70,000 feet. This is due to the centrifugal force created by the earth’s constant rotation. Mountains rising almost 30,000 feet and ocean trenches diving over 36,000 feet (compared to sea level) further distort the shape of the Earth. Sea level itself is even irregularly shaped. Slight variations in Earth’s gravity field cause permanent hills and valleys in the ocean’s surface of over 300 feet relative to an ellipsoid.
Additionally, the shape of the Earth is always changing. Sometimes this change is periodic, as is the case with daily tides that affect both the ocean and the crust; sometimes the change is slow and steady, as with the drift of tectonic plates or the rebound of the crust after a heavy sheet of ice has melted; and sometimes the shape of the planet changes in violent, episodic ways during events such as earthquakes, volcanic eruptions, or meteor strikes.
The National Geodetic Survey of the National Oceanic and Atmospheric Administration measures and monitors our ever-changing planet. Geodesy is the science of measuring and monitoring the size and shape of the Earth, including its gravity field, and determining the location of points on the Earth’s surface.
Image description: Although 75% of the planet is a relatively unchanging ocean of blue, the remaining 25% of Earth’s surface is a dynamic green. The darkest green areas are the lushest in vegetation, while the pale colors are sparse in vegetation cover either due to snow, drought, rock, or urban areas. Data from the NASA/NOAA Suomi NPP satellite is able to detect these subtle differences in greenness.
View and download more images and video animations of vegetation on Earth.
Image from NASA/NOAA.
Image description: NASA’s Cassini spacecraft captured this image of Earth and the moon from its perch in the Saturn system nearly 900 million miles away.
Pictures of Earth from the outer solar system are rare because from that distance, Earth appears very close to our sun. A camera’s sensitive detectors can be damaged by looking directly at the sun, just as a human being can damage his or her retina by doing the same. Cassini was able to take this image because the sun had temporarily moved behind Saturn from the spacecraft’s point of view and most of the light was blocked.
View more images of Earth from Cassini.
Image from NASA/JPL-Caltech/Space Science Institute.