More space news
Space News 1 - My Very Educated Mom Just Served Us Nachos
It's official, and all over the news so I'm not going into detail here: Pluto is no longer classified as a planet - it is now a "Dwarf Planet" along with Ceres, Charon, 2003 UB313 and others. This means that we now have eight planets in the solar system and the old mnemonic "My Very Educated Mother Just Served Us Nine Pizzas" will have to be rewritten.
On the other hand the decision may not stand for too long - the astronomers who voted on the proposed definition account for only a small percentage of professional astronomers worldwide and there have been some fairly strong objections to the new definition.
Space News 2 - First evidence for Dark Matter
Observations of the Bullet Cluster have provided the first hard evidence for the reality of Dark Matter. The Bullet Cluster is actually two galaxies that are passing through each other in opposite directions (I'm simplifying a bit, but this is essentially correct). As they pass, the stars in the galaxies miss each other because of the huge spaces between them, but the gas clouds are much larger so they bump into each other and slow down. The result is a cloud of gas in the middle with the stars passing out of the gassy region.
Measurements of the mass distribution show that the majority of the mass stays with the stars and not the gas - even though there's a lot more "normal" matter in the gas than there is in the stars. This shows that the Dark Matter is associated with the stars and not the gas. This puts us a step forward in understanding what Dark Matter may actually be.
Space News 3 - Mariner 4 mystery may be solved
In 1965 Mariner 4 took the first close pictures of the surface of Mars. Its job done, it cruised the space between Mars and Earth - it didn't have enough fuel to go anywhere else, so it simply drifted along with nothing to do.
On September 15, 1969, something strange happened - for 45 minutes Mariner 4 was sandblasted by a storm of meteors more intense than any seen here on Earth. And that's where the mystery began, because nobody had any idea where these meteors could have come from.
Until now, that is. Paul Weigert of the University of Western Ontario may have the answer. The trail goes back to 1895, when well-known comet spotter Lewis Swift found a comet which, by convention, was subsequently named "1895 Swift". The comet was seen again in 1896, heading out of the inner solar system on a 5-year orbit, but was never seen again. When it didn't show up as expected it was presumed to have disintegrated and renamed "D/Swift" for short (the "D" prefix indicating a comet that has disintegrated or been destroyed).
Weigert suggests that D/Swift broke up shortly after the last sighting in 1896, becoming a stream of small particles following the original orbital path of the comet. In 1967 Mariner 4 crossed that orbit just as the bulk of the broken-up D/Swift was passing. The calculations aren't certain because D/Swift was only seen a couple of times over a century ago, so the orbit isn't accurately known, but the indications are certainly compelling.
Comets like D/Swift break up all the time, so it's highly likely that the space all around the Earth and Mars is filled with particle streams just like the one that Mariner hit. This is important to know, since plans are afoot to send more spacecraft to Mars over the next few years.
It's official, and all over the news so I'm not going into detail here: Pluto is no longer classified as a planet - it is now a "Dwarf Planet" along with Ceres, Charon, 2003 UB313 and others. This means that we now have eight planets in the solar system and the old mnemonic "My Very Educated Mother Just Served Us Nine Pizzas" will have to be rewritten.
On the other hand the decision may not stand for too long - the astronomers who voted on the proposed definition account for only a small percentage of professional astronomers worldwide and there have been some fairly strong objections to the new definition.
Space News 2 - First evidence for Dark Matter
Observations of the Bullet Cluster have provided the first hard evidence for the reality of Dark Matter. The Bullet Cluster is actually two galaxies that are passing through each other in opposite directions (I'm simplifying a bit, but this is essentially correct). As they pass, the stars in the galaxies miss each other because of the huge spaces between them, but the gas clouds are much larger so they bump into each other and slow down. The result is a cloud of gas in the middle with the stars passing out of the gassy region.
Measurements of the mass distribution show that the majority of the mass stays with the stars and not the gas - even though there's a lot more "normal" matter in the gas than there is in the stars. This shows that the Dark Matter is associated with the stars and not the gas. This puts us a step forward in understanding what Dark Matter may actually be.
Space News 3 - Mariner 4 mystery may be solved
In 1965 Mariner 4 took the first close pictures of the surface of Mars. Its job done, it cruised the space between Mars and Earth - it didn't have enough fuel to go anywhere else, so it simply drifted along with nothing to do.
On September 15, 1969, something strange happened - for 45 minutes Mariner 4 was sandblasted by a storm of meteors more intense than any seen here on Earth. And that's where the mystery began, because nobody had any idea where these meteors could have come from.
Until now, that is. Paul Weigert of the University of Western Ontario may have the answer. The trail goes back to 1895, when well-known comet spotter Lewis Swift found a comet which, by convention, was subsequently named "1895 Swift". The comet was seen again in 1896, heading out of the inner solar system on a 5-year orbit, but was never seen again. When it didn't show up as expected it was presumed to have disintegrated and renamed "D/Swift" for short (the "D" prefix indicating a comet that has disintegrated or been destroyed).
Weigert suggests that D/Swift broke up shortly after the last sighting in 1896, becoming a stream of small particles following the original orbital path of the comet. In 1967 Mariner 4 crossed that orbit just as the bulk of the broken-up D/Swift was passing. The calculations aren't certain because D/Swift was only seen a couple of times over a century ago, so the orbit isn't accurately known, but the indications are certainly compelling.
Comets like D/Swift break up all the time, so it's highly likely that the space all around the Earth and Mars is filled with particle streams just like the one that Mariner hit. This is important to know, since plans are afoot to send more spacecraft to Mars over the next few years.
Labels: Science
posted by Pete Ford at
9:51 AM
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