Mercury's magnetic field. Strength[edit] Whether the magnetic field changed to any significant degree between the Mariner 10 mission and the MESSENGER mission remains an open question. A 1988 J.E.P. Connerney and N.F. Ness review of the Mariner magnetic data noted eight different papers in which were offered no less than fifteen different mathematical models of the magnetic field derived from spherical harmonic analysis of the two close Mariner 10 flybys, with reported centered magnetic dipole moments ranging from 136 to 350 nT-RM3 (nT is nanoteslas, RM is a Mercury radius of 2436 km).
In addition they pointed out "[e]stimates of the dipole obtained from bow shock and/or magnetopause positions (only) range from approximately 200 nT-RM3 (Russell 1977) to approximately 400 nT-RM3 (Slavin and Holzer 1979b). " Origins[edit] This dynamo is probably weaker than Earth's because it is driven by thermo-compositional convection associated with inner core solidification.
Magnetic poles and magnetic measurement[edit] Mercury (planet) Mercury is gravitationally locked and rotates in a way that is unique in the Solar System. As seen relative to the fixed stars, it rotates exactly three times for every two revolutions[b] it makes around its orbit.[13] As seen from the Sun, in a frame of reference that rotates with the orbital motion, it appears to rotate only once every two Mercurian years.
An observer on Mercury would therefore see only one day every two years. Because Mercury's orbit lies within Earth's orbit (as does Venus's), it can appear in Earth's sky in the morning or the evening, but not in the middle of the night. Also, like Venus and the Moon, it displays a complete range of phases as it moves around its orbit relative to Earth. Although Mercury can appear as a very bright object when viewed from Earth, its proximity to the Sun makes it more difficult to see than Venus. Two spacecraft have visited Mercury: Mariner 10 flew by in the 1970s and MESSENGER, launched in 2004, remains in orbit. Internal structure.
Mercury as Never Seen Before. Mercury as Never Seen Before Date: 6 Oct 2008 The spectacular image shown here is one of the first to be returned from MESSENGER's second flyby of Mercury. The image shows the departing planet taken about 90 minutes after the spacecraft's closest approach. The bright crater just south of the center of the image is Kuiper, identified on images from the Mariner 10 mission in the 1970s.
For most of the terrain east of Kuiper, toward the limb (edge) of the planet, the departing images are the first spacecraft views of that portion of Mercury's surface. A striking characteristic of this newly imaged area is the large pattern of rays that extend from the northern region of Mercury to regions south of Kuiper. This extensive ray system appears to emanate from a relatively young crater newly imaged by MESSENGER, providing a view of the planet distinctly unique from that obtained during MESSENGER's first flyby. Saturn. Catalog of Transits of Mercury. A transit is the passage of a planet across the Sun's bright disk.
At this time, the planet can be seen as a small black disk slowly moving in front of the Sun. The orbits of Mercury and Venus lie inside Earth's orbit, so they are the only planets which can pass between Earth and Sun to produce a transit. Transits are very rare astronomical events. In the case of Mercury, there are on average thirteen transits each century.
A transit of Mercury occurs only if the planet is in inferior conjunction with the Sun (between Earth and Sun) and is also crossing the through Earth's orbital plane (the Ecliptic). During the present period in Earth's history, Mercury's orbit crosses Earth's orbital plane in early May and early November each year. During the seven century period 1601 CE to 2300 CE1, Earth experiences 94 transits of Mercury across the Sun. All Transits = 94 = 100.0% May (Descending Node2) = 31 = 33.0 % November (Ascending Node3) = 63 = 67.0 % Footnotes Key to Catalog of Transits. Cassini Images of Seas on Titan. Cassini Spacecraft Images Seas on Saturn's Moon Titan Instruments on NASA's Cassini spacecraft have found evidence for seas, likely filled with liquid methane or ethane, in the high northern latitudes of Saturn's moon Titan.
One such feature is larger than any of the Great Lakes of North America and is about the same size as several seas on Earth. Cassini's radar instrument imaged several very dark features near Titan's north pole. Much larger than similar features seen before on Titan, the largest dark feature measures at least 100,000 square kilometers (39,000 square miles). Since the radar has caught only a portion of each of these features, only their minimum size is known. Image right: A comparison view of a lake on Titan and Lake Superior. "We've long hypothesized about oceans on Titan and now with multiple instruments we have a first indication of seas that dwarf the lakes seen previously," said Dr.
Chinese moon rover slated for 2012. EO Newsroom: New Images - IMAGE Spacecraft Pictures Aurora. From space, the aurora is a crown of light that circles each of Earth’s poles. The IMAGE satellite captured this view of the aurora australis (southern lights) on September 11, 2005, four days after a record-setting solar flare sent plasma—an ionized gas of protons and electrons—flying towards the Earth. The ring of light that the solar storm generated over Antarctica glows green in the ultraviolet part of the spectrum, shown in this image. The IMAGE observations of the aurora are overlaid onto NASA’s satellite-based Blue Marble image. From the Earth’s surface, the ring would appear as a curtain of light shimmering across the night sky. Like all solar storms, the September storm distorted the shape of the magnetic field that surrounds the Earth.
Since 2000, IMAGE has provided insight into how the Earth’s powerful magnetic field protects the planet from solar winds. Image courtesy NASA Instrument(s): Cassini Equinox Mission. Huygens CD on Titan. Huygens CD on Titan. Microbes on or within Saturn's moon Enceladus? Microbes on Enceladus? There’s a chance that Saturn’s sixth-largest moon, Enceladus, might harbor microbial life according to scientists studying information obtained by NASA’s Cassini spacecraft. The spacecraft is now making a series of tantalizingly close flybys to the moon, scientists said on March 27, 2012.
They said watery jets erupting from Enceladus might be coming from a vast underground sea. These jets, which spew through cracks in the moon’s icy shell, could lead back to a habitable zone, according to these scientists. Saturn closest, brightest, opposite the sun on April 15, 2012 Give me five minutes and I’ll give you Saturn in 2012 Saturn's moon Enceladus has active jets or geysers on its surface that are spewing water into space. The so-called tiger stripes on Saturn's moon Enceladus can be seen in this image, on the lower part of the moon.
When Porco says “organic” she means, “contains carbon compounds.” Enceladus' fascinating and mysterious jets. Said Porco: Saturn, Sixth Planet from Sun & Second Largest in Solar System | Gas Giant, Saturn’s Rings, Jovian Planet. Saturn is the sixth planet from the sun and the second largest planet in the solar system. Although the other gas giants in the solar system — Jupiter, Uranus and Neptune — also have rings, those of Saturn are without a doubt the most extraordinary. Saturn was the Roman name for Cronus, the lord of the Titans in Greek mythology. Saturn is the root of the English word "Saturday. " Physical characteristics of Saturn Saturn is a gas giant made up mostly of hydrogen and helium. Saturn is big enough to hold more than 760 Earths, and is more massive than any other planet except Jupiter, roughly 95 times Earth's mass. However, Saturn has the lowest density of all the planets, and is the only one less dense than water — if there were a bathtub big enough to hold it, Saturn would float.
Saturn is the farthest planet from Earth visible to the naked human eye. Saturn spins faster than any other planet except Jupiter, completing a rotation roughly every 10-and-a-half hours. Composition & structure. Saturn gets edgy. Observing Saturn through even a small telescope is amazing. The rings are so obvious and clear that sometimes, when I would show people the planet through my own ‘scope, they thought I was faking the view! But it really is that easy to see them. Well, usually. Saturn, like the Earth, is tilted. That is, if you imagine Saturn orbiting the Sun, the north pole doesn’t point straight up, perpendicular to the orbit.
"Amateur" astronomer Alan Friedman — who has taken some incredible pictures of the Sun that have graced this blog — took a series of images of Saturn over several years, and put them together in a very cool animation that shows our changing view of the ringed planet: Pretty nifty [click to encronosenate]! [Again, click to embiggen.] Right now, as the dance of the planets continues, Saturn is getting closer to the Sun in the sky, making it difficult to observe.
Image credit: Alan Friedman, used by permission. Related posts: - Ringless - Behold, Saturn!