Growing pains.
This artist's conception shows a neutron star known as a magnetar crackling with extremely powerful magnetic activity.
Credit: Gregg Dinderman/Sky & Telescope
Posted on 02/23/2008 9:05:41 PM PST by neverdem
Growing pains.
This artist's conception shows a neutron star known as a magnetar crackling with extremely powerful magnetic activity.
Credit: Gregg Dinderman/Sky & Telescope
"When you hear hoofbeats," the old saying goes, "think horse, not zebra." But what if your horse suddenly grows zebra stripes? That's the predicament astronomers faced when a star they were observing--a rapidly spinning remnant of a supernova called a pulsar--started emitting powerful bursts of x-rays considered the hallmark of a much-rarer object called a magnetar. The finding strongly suggests that pulsars, also known as neutron stars, and magnetars are linked and paves the way for a better understanding of stellar evolution.
Pulsars are the dense cores left over after stars of a certain mass explode into supernovae. Weighing as much or more than the sun but only as big as asteroids, they can rotate tens or even hundreds of times a second (versus once a day for Earth). Sky surveys have identified about 1800 pulsars within the Milky Way, most of which emit pulsing radio signals that rise and fall as the pulsars spin.
The stripe-changing pulsar, named PSR J1846-0258, lies about 20,000 light-years away in the constellation Aquila. A team of researchers from NASA and elsewhere was observing it using the Rossi X-ray Timing Explorer (RXTE) spacecraft when the star suddenly erupted in a blast of x-rays. The display, reported online today in Science, made PSR J1846-0258 a candidate for being a magnetar--a type of neutron star with an enormously powerful magnetic field. Magnetars, so rare that only a dozen or so have been discovered, routinely emit high-energy x-rays and even gamma rays. But no one had ever observed a pulsar emitting such bursts.
"The bursts were completely unexpected," says astrophysicist and lead author Fotis Gavriil of NASA's Goddard Space Flight Center in Greenbelt, Maryland. Because PSR J1846-0258 is a very young pulsar (a mere 1000 years old) and because its magnetic field strength is considerably lower than those from bona fide magnetars, Gavriil says, the researchers suspect it is still evolving. He says the discovery raises important questions about the two types of stars: Do pulsars behave like magnetars only periodically and then revert? Did all magnetars originate as pulsars? "We really need to follow this source, and others like it, to answer these questions," he says.
Astrophysicist Duncan Lorimer of West Virginia University in Morgantown calls the discovery "fantastic." A decade ago, he says, very little was known about any connections between pulsars and magnetars. Now, Lorimer says, the evolutionary connections between the two are strengthening, and observations like this one will help "elucidate our understanding of what happens to a young neutron star after its birth in a supernova." And astrophysicist Robert Duncan of the University of Texas, Austin, calls the findings "fascinating and important," because they represent the first time that magnetically generated x-rays have been seen coming from a rotationally driven pulsar. Duncan, who developed the theoretical behavior of magnetars in 1992, says he is not so sure the object will turn out to be a magnetar, but "neutron stars are constantly surprising scientists, so future observations … will certainly be interesting."
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Not if you have a really big test tube!
Ahhh...my eyes!!
Aha... finally, retaliation for those Zowie pictures... ;’)
How are they wrong?
Thanks for the ping.
How are they wrong?
This is a very nebulous statement, and I am not sure exactly what you mean by "proper scientific conduct." To be clear science is about providing explanations of things that are observed. When the explanation is generalized to expand to multiple observations, instances, or circumstances then it becomes a "theory." The validity of the generalized explanation, i.e. theory, is predicated on its ability to explain a broad class of observations, and great weight is placed on a theory that predicts unexpected things that turn out to be true.
Thus, for instance theories of conservation of energy, entropy, the Maxwell equations, and so forth have become accepted theories. The phlogiston theory is no longer accepted as an adequate explanatory fit to observed phenomenon and therefore is discredited.
Anomolies are particularly valued in scientific practice because they provide the means to further validate a theory, modify a theory, restrict the domain of validity of a theory, develop a new theory for an entirely different phenomenon, or develop an expanded theory of greater validity than the original theory.
(wink)
When will the faith in the exactness of Einstein's gravity theory finally break down? I mean, if mere falsifying observations were enough, it would be dead as a doornail by now.
“in” degrees per day - and “rotation” - darn typos, sorry for any confusion.
Hope you don't mind if I butt in here ;^)
Let me start by suggesting anyone NOT finding major problems wihtin the scientific community™ should actually declare their religion. Since scientology is taken, I offer as a suggestion, denialogy. That is, you accept on faith everything promulgated that protects their sacred cows or sacred cowboys. There is a bold new world out there for all disciplines of science -- with the exception of anything that could disturb the status quo. It would appear to the layman, simple minded people have obtained control of the flow of scientific information.
If you're truly interested in discovering why there are a few around that distrust much of mainstream science, just have a look at mainstream media. Their incessant spreading of cow manure has been exposed for most of the world to see; maybe it's time the same be done for the scientific community™.
The answer to both questions is no.
The Sun's sidereal period of rotation is 25.35 days; its synodic period -- the time for it to make a full rovolution plus the additional time required for it to "catch up" to compensate for Earth's rotation along its orbit around the Sun -- is 27.25 days.
The plane of Earth's orbit around the Sun, known as the "ecliptic," is the fundamental plane of reference in our solar system. On star maps it is shown as a line that marks the Sun's apparent path against the background of the stars during the course of a year. Earth's axis of rotation is inclined 23.75 degrees off a perpendicular to the ecliptic; the Sun's rotational axis is inclined 7.25 degrees off a perpendicular to the ecliptic.
Halton Arp: A Modern Day Galileo
Halton Arp is to the 21st century what Galileo was to the 17th. Both were respected scientists, popular leaders in their field. Both made observations which contradicted the accepted theories. Seventeenth century academics felt threatened by Galileo's observations and so, backed by ecclesiastical authority, they ordered him to stop looking. Twentieth century astronomers felt threatened by Arp's observations and so, backed by institutional authority, they ordered him to stop looking.
Both refused. Both published works geared to the non-specialist when specialists would no longer take note. Galileo's paper, "A Dialogue on the Two Chief Systems of the World" , favored a heliocentric model of the solar system and undermined the accepted geocentric model. Arp's books, Quasars, Redshifts and Controversies, Seeing Red, and Catalogue of Discordant Redshift Associations, favor a steady-state model of the universe and undermine the accepted big bang model.
The Church responded by placing Galileo under house arrest: his peers would not even look through his telescope and the Church judged his books heretical. The modern astronomical community responded similarly to Arp. Observatory officials cancelled his telescope time and astronomical journals refused to publish his research...
‘Unexpected’ is a fairly thin branch to decorate out like a righteous Christmas tree of anti-science rhetoric. Where did Galileo get off the track? Or if he didn’t, then where did Descartes fail to dig just a little deeper and miss paydirt?
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