Popular Mechanics summarizes how our knowledge of planets in the Solar System has changed over the last 30 years of space exploration.
Tags : Every space probe ever launched, all on one map of the Solar System.
Old moon?: The moon cooled to a solid 4.4 billion years ago.
Courtesy ViaMoi
Where did the moon come from?
Scientific studies indicate the solar system formed about 4.6 billion years ago and that about 4.5 billion years ago an object about the size of Mars hit the Earth, blasting away material that eventually cooled into what is now our moon. (Read more in Science News: "The Solar sytem's big bang")
How do we know the moon's age?
Rocks brought back from the moon contain zircon crystals. Zircons crystallize only after 80 to 85 percent of a volume of molten rock has solidified. By understanding how uranium within the zirconium breaks down into lead, scientists believe they know when the crystals formed with an error margin of less than 4 million years. The oldest zircons from the moon are about 10 million years older than the oldest yet discovered on Earth. The ages of lunar zircons identified in other studies hint that small amounts of the moon’s crust remained molten for another 200 million to 400 million years.
"Alexander Nemchin and his colleagues have used a uranium-lead dating technique to scrutinize a 0.5-millimeter-wide zircon embedded in a moon rock collected by Apollo 17 astronauts in December 1972. The crystal — which, although small, is rather large as zircons go — is about 4.417 billion years old, the researchers report online January 25 in Nature Geoscience."
Source:
Science News: "Oldest zircon fine-tunes history of moon's formation"
The edge of the Solar System is defined by the heliosheath, the point where the solar wind – a constant stream of high-energy particle emitting from the Sun – drops off abruptly. Rather than being perfectly spherical, it is pushed in at the bottom by an inter-stellar magnetic field. To which I say: huh.
If you were sad to see Pluto stripped of its planetary status, you can be glad that the poor mass of rock and ice has been given a break. The international body that officially defines the names of stellar objects has decided to call all objects like Pluto, plutoids. So if Pluto isn't a planet, what is it? It's a plutoid...so is Eris.
See Spots spin: In recent years, Jupiter has picked up a couple new red spots. While the Great Red Spot (right) has raged for hundreds of years, newer smaller red spots -- Red Spot, Jr., (middle) and "Baby Spot" (left) have emerged.
Courtesy M. Wong and I. de Pater (University of California, Berkeley)New images from the Hubble Telescope show that the Giant Planet has picked up a couple more red spots, smaller but very near to the Great Red Spot.
Images taken earlier this month discovered the third red spot on the planet, which has been nicknamed “Baby spot.” Red Spot, Jr., was discovered in spring 2006. The Great Red Spot, which is a raging storm about the same size as our Earth, has been churning in Jupiter’s atmosphere for 200 to 350 years.
“Baby Spot” had been a white storm prior to taking on its reddish appearance. Scientists believe the red color come from clouds reacting to solar ultraviolet radiation.
Why is Jupiter getting a surge of extra red spots? Researchers think that it has to do with climate changes on the planet. In 2004 a California astronomer predicted that the planet was moving into a phase of warming temperatures that would destabilize its atmosphere.
“Baby Spot” is on a collision course with the Great Red Spot and could be gobbled up by it later this summer or bounced into a different location on the planet.
Encladaeus, a moon of Saturn, is emitting jets of very pure water, forcing scientists to reconsider just what the heck is going on up there.
The Orion crew exploration vehicle: This rendering represents a concept of the Orion crew exploration vehicle. Image courtesy: Lockheed Martin Corp.Scientific American.com has a cool interactive on what they think the Five Goals for Exploring the Solar System should be. Check it out, and then think about what you think our goals for exploring the solar system should be. What do you think?
At the Science Museum of Minnesota you can ask our featured Scientist on the Spot a question either using a computer interface or the old fashioned way – with a paper and pencil. Some of the handwritten questions veer a little off topic. But they are still good questions, and deserve answers. So here’s a question that was a little off topic for Noelle Beckman: “Can you tell me about Jupiter?”. Noelle is a graduate student at the University of Minnesota who studies how animals influence the make-up of tropical forests. So, I’ll take this one.
Jupiter: Image courtesy NASA.Jupiter is the largest of the eight planets in our solar system (remember, poor Pluto is no longer considered a planet). Jupiter is a gas giant, meaning it is primarily made up of hydrogen (90%) and helium (10%) gases. Jupiter probably has a rocky or metallic core, though we don’t know that for certain.
Jupiter is huge – really, tremendously big. Not as big as the Sun, but bigger than all the planets (even including Pluto) combined.
The Great Red Spot: Image courtesy NASA.When you look at the picture of Jupiter above, you can see that Jupiter’s atmosphere is banded – this banding is typical of gas giants (see pictures of the other gas giants in our solar system, Saturn, Uranus and Neptune, to see similar banding). The bands are the result of extremely fast winds (more than 400 miles per hour) that are blowing in opposite directions for each adjacent band. The interaction of these bands result in storms – and one of Jupiter’s storms, called the Great Red Spot, has been known to exist since the seventeenth century.
Several NASA spacecraft have visited Jupiter, including Pioneers 10 & 11, Voyagers 1& 2, Galileo, New Horizons, Cassini-Huygens (on its way to Saturn), Ulysses (which used Jupiter in gravity-assist maneuver) – and probably others I was not able to dig up.
Jupiter has many moons – from what I can tell the current count is 63 – 47 of them are smaller than 10 kilometers in diameter. The four best known moons are Io, Europa, Ganymede and Callisto.
What else can I tell you? The comet Shoemaker-Levy 9 collided with Jupiter in 1994. You can see Jupiter in the night sky right now (in the southern sky during twilight and lower in the southwest after dark). Jupiter was named after the Roman god, Jupiter, who was very similar to Zeus in the Greek pantheon. In Pompeii there was a temple to Jupiter at the north end of the forum. Jupiter has faint planetary rings, like Saturn.
I hope this answers this person’s question. See, I can tell you about Jupiter!
Hot comet: Results of research from the Stardust comet particle retrieval mission are showing that the surface of comet Wild2 is composed of materials from the inner portions of our solar system. It used to be believed that comets were composed of matter from the outer regions of our solar system.What makes up a comet?
Scientists are starting to find out as they dig into the samples of a comet collected through the recent Stardust space mission. And they’re finding out that a comet is made up a of lot more than space’s intergalactic dust bunnies, which used to be the original concept of comet formation..
Testing on the samples from the Comet Wild2 are showing that it is made up of hot particles from the inner solar system that drifted out to the colder ranges of the our solar system around Pluto’s orbit. Prior to these finding, astronomers thought that comets were made up from tiny, cold space particles from regions of space further out of our solar system that were drifting into our system.
After doing the recent tests on Wild2’s comet dust, researchers are now estimated that around ten percent of a comet’s make up could have come from our inner solar system near the sun. How those particles have ended up as part of a comet are still a mystery to researchers, however. It may be the result of the chaotic activity at the forming of the solar system when “hot” inner solar systems were blasted out into the outer reaches of space.
And scientists are finding out that not all comets are created equal. Dust from Wild2 is very different from that of Tempel1, which was studied by NASA’s Deep Impact mission. On that mission, NASA last July crashed a probe into a comet and analyzed the dust and ice that spewed out from the crash. No surface materials were analyzed.
With Wild2, the Stardust mission sent a capsule around the sun and then swooping past Wild2 to scrape up thousands of tiny samples of comet surface materials. That capsule returned to Earth in January for scientists to begin analyzing the make up of the comet’s surface.
Some of the minerals found in the Wild2 dust are “high-temperature” minerals that were likely formed in the hottest portions of our solar system.
Subscribe
I want to learn about
Science Buzz is supported by the National Science Foundation.Copyright © Science Museum of Minnesota, 2004-2010, except where noted.
Add a new comment