Posts tagged solar system
Posts tagged solar system
(Not including Earth)
Our of curiosity, I made a survey for this. Mostly because I’m interested in what people consider “interesting” when it comes to these things, but also whether or not that impacts how much you like it. But please do not answer the questions unless you have an actual answer for both of them. In other words, don’t just choose one randomly without giving it any thought.
The survey can be found here. I’ll post the results a week from today, on January 13th.
Is Pluto a planet? Does it qualify? For an object to be a planet, it needs to meet these three requirements defined by the IAU:
- It needs to be in orbit around the Sun – Yes, so maybe Pluto is a planet.
- It needs to have enough gravity to pull itself into a spherical shape – Pluto…check
- It needs to have “cleared the neighborhood” of its orbit – Uh oh. Here’s the rule breaker. According to this, Pluto is not a planet.
Even the mighty can lose heart. New calculations suggest that Jupiter’s rocky core is dissolving like an antacid tablet plopped in water.
The work could help explain why its core appears smaller and its atmosphere richer in heavy elements than predicted.
Giant planets like Jupiter and Saturn are thought to have begun their lives as solid bodies of rock and ice. When they grew to about 10 times the mass of Earth, their gravity pulled in gas from their birth nebula, giving them thick atmospheres made mainly of hydrogen.
Curiously, some studies have suggested that Jupiter’s core may weigh less than 10 Earths, while the core of its smaller sibling Saturn packs a bigger punch at 15 to 30 Earths. Last year, researchers led by Shu Lin Li of Peking University in China offered a grisly explanation – a rocky planet bigger than Earth slammed into Jupiter long ago, vaporising most of the giant planet’s core.
That scenario could also explain another mystery – why Jupiter’s atmosphere contains a higher fraction of heavy elements than the sun, whose composition is thought to mirror that of the nebula that gave birth to the solar system’s planets.
Now Hugh Wilson and Burkhard Militzer of the University of California, Berkeley, suggest a competing – though no less macabre – explanation: Jupiter’s core has gradually been dissolving since its formation 4.5 billion years ago.
View of Juno’s position on Aug. 24 from Eyes on the Solar System. (Click for an expanded view.)
See the Juno spacecraft’s current position and velocity using NASA’s Eyes on the Solar System 3D interactive (free web browser plugin required) or the NASA/JPL Solar System Simulator.
The MPG/ESO 2.2-metre telescope at La Silla in Chile is a powerful instrument that can capture distant celestial objects, but it has been used here to image a heavenly body that is much closer to home: the Moon. The data used for this image were selected by Andy Strappazzon from Belgium, who participated in ESO’s Hidden Treasures 2010 astrophotography competition. Andy’s composition of the Moon was the fourth highest ranked entry in the competition.
This image of the crescent Moon shows sunlight skimming across the heavily pocked surface, filling its craters with shadows. This is a fairly flat region of the Moon, but elsewhere, high mountains can be found, with some peaks reaching about 5000 metres. When backlit by the Sun, these mountains cast long shadows on the lunar surface. In the 1600s, Galileo Galilei used these long shadows to determine the height of the peaks.
At the Moon’s poles (not seen in this picture), some craters are permanently shadowed and the floors of some may have not seen sunlight for billions of years. Scientists had long suspected that these dark and constantly cold regions of the Moon could harbour water ice, but it wasn’t until late 2009 that evidence for this was found.
In a NASA mission called LCROSS (Lunar Crater Observation and Sensing Satellite), a spent rocket booster was sent on a one-way collision course to the Moon’s south pole, while the remaining part of the spacecraft hunted for evidence of water in the ejected debris. The mission was a success and its findings confirmed the presence of water ice within these dark craters. The finding has important implications for the future of human exploration of the Moon and elsewhere in the Solar System.
An interactive 3-D model of the solar system
(F. Scholten, DLR. NASA/GSFC/ASU/WUSTL)The nature of the terrain jumps out when orbiter camera images are draped over a digital terrain model created with those images. At the center of the province is an irregular depression that might well be a caldera and at its edges are domes with features that suggest they were formed by the intrusion of high-viscosity silicic lava, a type of lava rare on the moon. Any model of the moon’s thermal evolution must now be able to account for this volcanic province as well as the familiar mare.
Silicate volcanoes are a type that do not ooze magma; deeming them “dead” by scientists. Other basaltic or active volcanoes have been discovered on the moon’s surface in the past.
“Most of the volcanic activity on the moon was basaltic,” said primary author Brad Joliff of Washington University to SPACE.com in an email. “Finding other volcanic types is interesting as it shows the geologic complexity and range of processes that operate on the moon, and how the moons volcanism changed with time.”
According to research compiled by the journal Nature Geoscience, the moons far side was not visible from the Earth due to tidal forces between it and the moon, until 1959 when the Soviet Union’s Luna 3 Spacecraft took pictures of the region.
In 1998, NASA’s Lunar Prospector probe circled the moon’s surface revealing a highly reflective plain lying between two ancient impact craters which is now known as the Compton-Belkovich region.
The silicate rocks and thorium found in this region suggested a more involved type of volcanic activity similar to that which created the moons well-known dark plains of basaltic plains known as “maria”, or “seas.”
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But once LRO captured higher resolutions of the region, scientists were able to confirm this kind of volcanic activity, after their spacecraft found a number of domelike features with steeply sloping slides.
According to Joliff, the domes were likely formed by lava which came from within the moon that flowed up through cracks to pool just beneath the moon’s surface, which then pressed out to create them.
He also stated that the silicate volcanoes on the far side of the moon are estimated to be around 800 years old, extending the volcanic activity of the moon by 200 million years.
But despite this newest discovery, NASA’s plans to return to the moon were canceled for 2010 and after according to Wired.
Artist Ron Miller takes us on a journey to eight of the most
breathtaking views that await explorers of our solar system.
The scale of these natural wonders dwarfs anything Earth has to offer.
What might we see and feel if we could travel to these distant domains?
By interpreting data from probes such as NASA’s Cassini, which is now
exploring the Saturnian system, and MESSENGER, which goes into orbit
around Mercury in March 2011, the artist’s eye allows us an early visit
to these unforgettable locales.
Two decades of searching have failed to turn up another planetary system like ours. Should we be worried?