Stories tagged planets
NASA Science website is an awesome resource
NASA Science website
Courtesy NASA To show how useful this site can be, here are links to pages I found as I dug deeper into just one of the many areas on the NASA Science website.
Science for different levels of learning
The NASA Science website provides learning opportunities for four learning groups.
Earth, sun, planets, and astrophysics
The NASA Science website is divided into these parts.
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Planet Waterslide: A digital reconstruction of "the most fun planet."
Courtesy **Mary**There was a brief period in the history of the solar system about 3.9 billion years ago characterized by wayward space particles pelting the inner planets. The period is referred to as the Late Heavy Bombardment, and the moon still bears the crater scars of the repeated impacts (Earth was similarly battered, but the constant recycling of the crust has erased the craters).
The prevailing theory behind the LHB has long been that early reshuffling of the planets was responsible – specifically that a rebellious young Neptune moved further out from the sun (perhaps seeking a place of its own) and disturbed rocky bodies in the Kuiper Belt, causing them to “veer into the inner solar system.”
Recently, an astrophysicist at the Carnegie Institution in Washington DC has provided compelling evidence that a migrating Neptune may not have been the cause after all. He thinks that the impact craters on the moon more closely match asteroids from the Asteroid Belt just beyond Mars, and that these asteroids were sent there by a disturbed orbit of a fifth rocky planet (the other rocky planets being, of course, Mercury, Venus, Earth, and Mars).
The planet, dubbed Planet V, would probably have been bigger than the moon, but slightly smaller than Mars. The Carnegie scientist even developed a computer model detailing how Mars’ gravity could have upset V’s orbit, causing it to fall into the sun, passing through the Asteroid Belt and scattering asteroids on its way.
The theory obviously requires extensive testing before it can be accepted with any confidence, but, so far, it has passed the test of whether or not I like it. I do like it.
I’m not terribly attached to the name, though. “V” is okay, I supposed, but it’s been done. I was thinking that something along the lines of “Planet Waterslide” would be better, not only because it sounds fun, but because it more accurately describes the character of the planet as suggested by my own theories. See, I predict that further research will reveal that “V” was covered in waterslides, and inhabited solely by kittens and friendly dinosaurs (neither of whom, ironically, ever used the waterslides). Planet Waterslide was the destiny of mankind, the universe’s reward for our inevitable achievement of interplanetary travel. Unfortunately, jealous Mars, not as brave as his big brother Neptune, and who never moved out of the parents’ basement of the solar system, tricked, or possibly tripped, its little brother Waterslide.
From this point, the Carnegie theory pretty much takes over. Except that the asteroid craters on the moon, should they receive further study, will no doubt prove to be interspersed with much smaller, fluffier craters.
Sky spy: This new device -- the SkyScout -- uses GPS to take all the guess work out of astronomy. Point the videocamera-sized unit at light in the heavens and it wiil identify what it is. (Photo from Celestron)Looking for that special gift for the astronomer who has everything?
Have you heard about SkyScout? It’s a nifty new tool that costs about $400 but makes identifying things you spot in the heavens a lot easier.
About the size of video camera, the unit made by Celestron can help you identify a particular light you’re seeing in the sky. Or, you can punch in key data and have scan the skies so you can find a particular star or planet.
How does it work?
When you turn on the unit, SkyScout’s global positioning systems first work to identify where you’re at and what day and time it is. By placing the object you want to identify at the center of its concentric circle viewing scope, it then reads landmark stars and objects in the sky to zero in on the item you’re interested in. An audio option can be turned on so that SkyScout will verbally tell you what you’re looking at.
On the flip side, if you want to find Venus, let’s say, you’d simply click on that celestial body on the SkyScout’s menu. Arrows in the viewfinder will guide to move SkyScout in the right directions to that you ultimately get it in your sights. SkyScout has a database of 6,000 heavenly bodies to search out that way.
A Star-Tribune story that ran over the weekend about the unit said that one local astronomy store – Radio City in Moundsview – can’t keep the units on the shelf. And a competitor product, MySky, has just entered the market.
What do you think of this new application of GPS? Have you tried a SkyScout or MySky? Share your thoughts here with other Science Buzz readers.
This new device -- the SkyScout -- uses GPS to take all the guess work out of astronomy. Point the videocamera-sized unit at light in the heavens and it wiil identify what it is. (Photo from Celestron)
Please contact us if you have questions about the rights on this image.
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!
Venus and Mars are alright tonight: They may not teach us much about conditions on Earth, but they provide hours of entertaining temperature conversion! Photo of Venus (left) from NASA; photo of Mars (other guy) from the Library of Congress.
As Science Buzz's resident global warming skeptic, I've taken a lot of shots at Al Gore over the years. Today, however, I find myself in the unusual position of having to defend him against unfair attacks. Somewhat.
In an editorial last Sunday, Gore stated:
“Consider this tale of two planets. Earth and Venus are almost exactly the same size, and have almost exactly the same amount of carbon. The difference is that most of the carbon on Earth is in the ground - having been deposited there by various forms of life over the last 600 million years - and most of the carbon on Venus is in the atmosphere.
As a result, while the average temperature on Earth is a pleasant 59 degrees, the average temperature on Venus is 867 degrees. True, Venus is closer to the Sun than we are, but the fault is not in our star; Venus is three times hotter on average than Mercury, which is right next to the Sun. It's the carbon dioxide.”
This got a bunch of bloggers to thinking. George Reisman went to a NASA website and found an interesting comparison:
| PLANET | Venus | Earth | Mars |
| CO2 IN ATMOSPHERE | 96% | 0%* | 95% |
| AVERAGE TEMPERATURE | 867˚F | 59˚F | -81˚F |
*Not quite true: Earth’s atmosphere is 0.035% CO2.
So, planets with lots of carbon in their atmosphere can be either broiling hot or icy cold.
(Another writer, Evan Kayne, complained (seventh item) the comparison isn't fair; Reisman didn’t take into account the fact that the atmosphere on Mars is only 1.3% as thick as Earth’s. James Taranto of the Wall Street Journal re-did the calculations, and concluded that frigid Mars still has 34x as much CO2 per cubic foot of atmosphere as the Earth does.)
So far, Al isn't looking too good. But then, blogger David Downing thought he'd discovered another problem. According to the NASA site, Mercury has an average temperature of 452˚ Kelvin, while Venus has an average temp of 726˚ Kelvin. That’s only 1.6 times hotter, a far cry from what Gore had claimed!
Wait a minute. What’s this “Kelvin” scale and why is Downing using it? Well, all temperature scales measure energy. And on the Kelvin scale, 0 degrees means “no energy AT ALL.”
This makes it very easy to compare the energy in different systems. In Celsius, 0 degrees doesn’t mean “zero energy;” it means “the amount of energy in frozen water” -- which may seem chilly to you and me, but at a molecular scale, it’s got plenty of heat. (0 degrees Fahrenheit is apparently the amount of energy in a mix of ice, water, and ammonium chloride.) Comparing 25˚F to 50˚F is tricky, because the scale doesn't stop at 0. As any Minnesotan knows, it goes wayyyyy lower than that!
(It’s kind of like saying “Mike is five years older than me; Vic is 10 years older than me; therefore, Vic is twice as old as Mike.” That would only be true if I were 0 years old. If I were, say, 47, then Mike would be 52 and Vic would be 57, and the differences would be much less impressive.)
So, Downing assumed Gore must have been working in Fahrenheit, and believed that if Venus is 867˚F and Mercury is 289˚F, then Venus is three times hotter. Ha ha, what a silly mistake! I was all prepared to poke fun at Al for this glaring error, until I realized – Mercury isn’t 289˚F. According to NASA, it’s a toasty 354˚F.
So, where did Al get 289˚F? I looked in a bunch of sources -- no one was even close. Wikipedia listed Mercury at a mere 26˚F. (The side facing the Sun broils; the side turned away freezes; this is an average.)
But then I noticed -- 26˚F is 270˚K. And Wikipedia lists Venus at 735˚K . Using the proper Kelvin scale, that works out to 2.7 times hotter than Mercury. Not quite 3 times, but in the ballpark. And, to be fair, Wikipedia gives Mercury a range of temperatures, and “3x hotter” fits comfortably within that range.
So, it turns out Gore was closer to being right than he’s given credit for. He WAS working in the proper Kelvin scale. He was just relying on figures from Wikipedia rather than from NASA.
I don’t know if all this has taught us anything about global warming. But man, have I learned a lot about planetary atmospheres, temperature scales, and math! Thanks, Al!
UPDATE: Evan Kaye had claimed that the atmosphere on Mars is only 2% as thick as Earth's. James Taranto, using figures from the NASA site linked to above, calculated that it is actually 1.3% as thick as Earth's. We have corrected the figure.
They may not teach us much about conditions on Earth, but they provide hours of entertainment for temperature conversion! Photo of Venus (left) from NASA; photo of Mars (other guy) from the Library of Congress.
Please contact us if you have questions about the rights on this image.
Demoted again: Pluto's ego took another blow this week when it was discovered that dwarf planet Eris is slightly bigger than the former "official" planet. (Drawing courtesy of NASA)I guess you could call Pluto the Rodney Dangerfield of our solar system…it just doesn’t get any respect.
Last summer Pluto got demoted from an official planet in our solar system and placed in a new category of heavenly bodies: dwarf planets. Now with more research, it’s been determined that Pluto isn’t even among the largest of the dwarves.
Eris is the cause of all of this turmoil of Pluto’s status. That dwarf planet was discovered to have similarities to Pluto and led astronomers to relook at how they define planets. Pluto and Eris were both bumped into the dwarf plant status. Now, the size of Eris has been measured: a diameter of 1,490 to 1,860 miles. Pluto’s diameter is a shade smaller: 1,430 miles.
All of these details came to light after astronomers discovered a moon, Dysnomia, circling Eris. Judging from the speed that Dysonmia has spinning around Eris, researchers have determined that Eris is about 27 percent heavier than Pluto as well. Both dwarf planets are made up primarily of rock and ice.
Don’t worry about any physical effects from this growing dwarf planet rivalry. Eris’ orbit is about twice as far away from the sun as Pluto’s. They’re a quite safe distance apart from each other.
To the Moon, Alice!: China and India are planning to send probes to Earth's closest neighbor. (Photo by NASA)
I don't do a lot of space-related posts. I find outer space kind of boring. But there have been a few stories lately that caught my eye.
Back to the moon
For the last couple of years, there's been talk of the US going back to the Moon. It looks like we might have some company when we get there. China and India recently announced their separate plans to send unmanned probes to the moon. China wants to study the chemical composition of the Moon’s surface, while India plans to create a 3D map of the satellite.
More planets than you can shake a stick at
Scientists at the University of California at Berkely have announced the discovery of 28 more planets outside of our Solar System, bringing the total to 236. They also discovered seven more “brown dwarfs” – which are basically stars that failed to ignite. Some scientists speculate that brown dwarfs may account for the missing “dark matter” whose gravity holds the Universe together.
And finally,
Hi-res Mars images
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