Earth From Space

Epic view of moon transiting Earth

Full Moon, Full Earth   NASA - August 7, 2015

The Moon was new on July 16. Its familiar nearside facing the surface of planet Earth was in shadow. But on that date a million miles away, the Deep Space Climate Observatory (DSCOVR) spacecraft's Earth Polychromatic Imaging Camera (EPIC) captured this view of an apparently Full Moon crossing in front of a Full Earth. In fact, seen from the spacecraft's position beyond the Moon's orbit and between Earth and Sun, the fully illuminated lunar hemisphere is the less familiar farside. Only known since the dawn of the space age, the farside is mostly devoid of dark lunar maria that sprawl across the Moon's perpetual Earth-facing hemisphere. Only the small dark spot of the farside's Mare Moscoviense (Sea of Moscow) is clear, at the upper left. Planet Earth's north pole is near 11 o'clock, with the North America visited by Hurricane Dolores near center. Slight color shifts are visible around the lunar edge, an artifact of the Moon's motion through the field caused by combining the camera's separate exposures taken in quick succession through different color filters. While monitoring the Earth and solar wind for space weather forcasts, about twice a year DSCOVR can capture similar images of Moon and Earth together as its crosses the orbital plane of the Moon.

  From a Million Miles Away, NASA Camera Shows Moon Crossing Face of Earth   NASA - August 6, 2015
These images were taken between 3:50 p.m. and 8:45 p.m. EDT on July 16, showing the moon moving over the Pacific Ocean near North America. The North Pole is in the upper left corner of the image, reflecting the orbital tilt of Earth from the vantage point of the spacecraft. This animation features actual satellite images of the far side of the moon, illuminated by the sun, as it crosses between the DSCOVR spacecraft's Earth Polychromatic Imaging Camera (EPIC) and telescope, and the Earth - one million miles away. EPIC maintains a constant view of the fully illuminated Earth as it rotates, providing scientific observations of ozone, vegetation, cloud height and aerosols in the atmosphere. Once EPIC begins regular observations next month, the camera will provide a series of Earth images allowing study of daily variations over the entire globe. About twice a year the camera will capture the moon and Earth together as the orbit of DSCOVR crosses the orbital plane of the moon.

Earth from Space: A southern summer bloom   PhysOrg - January 16, 2012

In this Envisat image, a phytoplankton bloom swirls a figure-of-8 in the South Atlantic Ocean about 600 km east of the Falkland Islands. During this period in the southern hemisphere, the ocean becomes rich in minerals from the mixing of surface waters with deeper waters. Phytoplankton depend on these minerals, making blooms like this common in the spring and summer. Read more at:

Strange Magnetic Portal Connects Earth to Sun - November 3, 2008

Like giant, cosmic chutes between the Earth and sun, magnetic portals open up every eight minutes or so to connect our planet with its host star. Called a flux transfer event, or FTE, such cosmic connections not only exist but are possibly twice as common as anyone ever imagined, according to space scientists who attended the 2008 Plasma Workshop in Huntsville, Ala., last week. Once the portals open, loads of high-energy particles can travel the 93 million miles (150 million km) through the conduit during its brief opening, space scientists say.

Researchers have long known that the Earth and sun must be connected. For instance, particles from the sun are constantly whisked away via the solar wind and often follow magnetic field lines that connect the sun's atmosphere with terra firma. The field lines allow particles to penetrate Earth's magnetosphere, the magnetic bubble that surrounds our planet. Several speakers at the workshop outlined the formation of a flux transfer event. One idea is that on the side of Earth facing the sun, our magnetic field presses against the sun's magnetic field. And about every eight minutes, the two fields briefly reconnect, forming a portal through which particles can flow. The portal takes the form of a magnetic cylinder about as wide as Earth.

Astrophysicist Jimmy Raeder of the University of New Hampshire used those measurements to develop computer simulations of the portals. He found the cylindrical portals tend to form above Earth's equator and then in December, the FTEs would roll over the North Pole. In July, they roll over the South Pole.

When the magnetic cylinders are active, they allow particles to flow through rather easily, forming important conduits of energy for Earth's magnetosphere, Sibeck said. When passive, the cylinders have more resistance to transiting particles. The internal structure of a passive cylinder makes it tougher for particles and magnetic fields to flow through. Sibeck has calculated the properties of passive FTEs and hopes he and his colleagues will hunt for signs of them in data collected with THEMIS and Cluster. The space scientists at the workshop still want to figure out why the portals form every eight minutes and how magnetic fields inside the cylinders twist and coil.

  Earth's Alien Sounds: Listen to sounds from space - July 1, 2008
These radio waves, called Auroral Kilometric Radiation (AKR), are created high above Earth where solar particles interact with the planet's magnetic field. Earth gives off a relentless hum of countless notes completely imperceptible to the human ear, like a giant, exceptionally quiet symphony, but the origin of this sound remains a mystery. Now unexpected powerful tunes have been discovered in this hum. These new findings could shed light on the source of this enigma. The planet emanates a constant rumble far below the limits of human hearing, even when the ground isn't shaking from an earthquake. (It does not cause the ringing in the ear linked with tinnitus.) This sound, first discovered a decade ago, is one that only scientific instruments - seismometers - can detect. Researchers call it Earth's hum.