Pulsars slow down their rotation as they age and eventually cease their characteristic emissions. That can change if an aging pulsar is a member of a binary system containing a normal star. Gas flowing from the star can spin the pulsar up to hundreds of revolutions a second and allow it to resume its lighthouse-like beams of radiation. Credit: NASA
Radio searches netted 17 new millisecond pulsars by examining the Fermi Gamma-ray Space Telescope’s list of unidentified sources. Colored circles indicate the positions of the new pulsars on the Fermi one-year all-sky map. Credit: NASA/DOE/Fermi LAT Collaboration
› Larger image Radio astronomers have uncovered 17 millisecond pulsars in our galaxy by studying unknown high-energy sources detected by NASA’s Fermi Gamma-ray Space Telescope. The astronomers made the discovery in less than three months. Such a jump in the pace of locating these hard-to-find objects holds the promise of using them as a kind of “galactic GPS” to detect gravitational waves passing near Earth.
A pulsar is the rapidly spinning and highly magnetized core left behind when a massive star explodes. Because only rotation powers their intense gamma-ray, radio and particle emissions, pulsars gradually slow as they age. But the oldest pulsars spin hundreds of times per second — faster than a kitchen blender. These millisecond pulsars have been spun up and rejuvenated by accreting matter from a companion star.
“Radio astronomers discovered the first millisecond pulsar 28 years ago,” said Paul Ray at the Naval Research Laboratory in Washington. “Locating them with all-sky radio surveys requires immense time and effort, and we’ve only found a total of about 60 in the disk of our galaxy since then. Fermi points us to specific targets. It’s like having a treasure map.”
Millisecond pulsars are nature’s most precise clocks, with long-term, sub-microsecond stability that rivals human-made atomic clocks. Precise monitoring of timing changes in an all-sky array of millisecond pulsars may allow the first direct detection of gravitational waves — a long-sought consequence of Einstein’s relativity theory.
“The Global Positioning System uses time-delay measurements among satellite clocks to determine where you are on Earth,” explained Scott Ransom of the National Radio Astronomy Observatory in Charlottesville, Va. “Similarly, by monitoring timing changes in a constellation of suitable millisecond pulsars spread all over the sky, we may be able to detect the cumulative background of passing gravitational waves.”
The sources Fermi detected are not associated with any known gamma-ray emitting objects and did not show evidence of pulsing behavior. However, scientists considered it likely that many of the unidentified sources would turn out to be pulsars.
For a more detailed look at radio wavelengths, Ray organized the Fermi Pulsar Search Consortium and recruited a handful of radio astronomers with expertise in using five of the world’s largest radio telescopes — the National Radio Astronomy Observatory, Robert C. Byrd Green Bank Telescope in W.Va., the Parkes Observatory in Australia, the Nancay Radio Telescope in France, the Effelsberg Radio Telescope in Germany and the Arecibo Telescope in Puerto Rico.
After studying approximately 100 targets, and with a computationally intensive data analysis still under way, the discoveries have started to pour in.
“Other surveys took a decade to find as many of these pulsars as we have,” said Ransom, who led one of the discovery groups. “Having Fermi tell us where to look is a huge advantage.”
Four of the new objects are “black widow” pulsars, so called because radiation from the recycled pulsar is destroying the companion star that helped spin it up.
“Some of these stars are whittled down to masses equivalent to tens of Jupiters,” said Ray. “We’ve doubled the known number of these systems in the galaxy’s disk, and that will help us better understand how they evolve.”
NASA’s Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership, developed in collaboration with the Department of Energy, along with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden, and the U.S. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.
Francis Reddy
Goddard Space Flight Center
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1. Astronomers lack the ability to sample most observed objects. Most observed objects are at distances which are large compared to our travel abilities. We cannot go there and come back. We can’t even get inside our own Sun. Except by inference. And mathematical physics.
2. Information about astronomical objects must, therefore, be inferred. The story of inference is long and detailed; I will give just one example. Until very recently (astrographic satellites), parallax proved a very poor method for determining stellar distance. By careful and tedious means Eddington derived the mass-luminosity relationship. Some stars occur in pairs (double stars). Among the double stars there are a few which orbit one another sufficiently rapidly for detailed orbit computations. Combining the observed luminosity and the orbit characteristics allows the determination of the actual size of the orbit, thus the distance. As I said, this is very tedious.
3. Recent advances in the detection of electromagnetic radiation from astronomical sources has provided data for which most assumptions are invalid. Pulsars are one type of radiation source. A long series of inferences has been used to rule out possibilities; the remaining (most likely) pulsar source is a rapidly spinning star remnant, which lacks fusible elements and is kept from ultimate collapse by nuclear pressure. By the way, ever watch an ice skater spin? As they pull their arms in towards their bodies, they spin faster. The angular momentum in the infalling gas cannot be lost; instead, that momentum speeds up the star.
4. If you do not accept neutron stars, come up with another theory which is conisistent with the observed variation in the intensities of successive pulses. There are lots of observations out there. Do your best!
5. The same observations that I have made about neutron stars apply to black holes. If you do not like the idea (Eddington certainly did not), come up with another theory. The arguments are multi-step, the math is formidable, and the observations (from the Chandra observatory and others) keep piling up.
6. As for lack of observation: the Fraunhofer absorption spectrum of Iron XIV could not be duplicated in the laboratory for many years. That did not mean the lines were not in the Solar spectrum. They simply could not be accounted for. The arguments were fierce. The same was true for helium. Perhaps the new CERN supercollider will produce neutronium for sufficiently many attoseconds for some analysis to take place. Who knows? That’s why we do experiments.
P.S.
See any of several works by Stephen Hawking or Roger Penrose for more information about what is currently known about neutron stars, black holes, and stellar evolution. The whole story is far from over.
As for gravity waves, several LIGO experiments are underway. Longwave Interferometric Gravity Observations, I believe. These are long evacuated tunnels in which standing waves are set up and monitored. In theory a gravity pulse would glitch the standing wave. This is, of course, after Joe Weber’s attempts at the University of Maryland were not successful.
Who knows? The merging of two orbiting black holes would certainly make a distinctive signature!
Dr. Manuel, if you don’t claim the existence of “neutronium”:
Dr. Manuel wrote: “…I did not claim the existence of ‘neutronium’.”
Well, what are your “Neutron stars” made from?
It is my understanding that so-called “neutron stars” are supposedly made from “neutronium”.
REPLY: This discussion is OVER, its off topic and stupid, and Dr. Manual please refrain from posting any more link bombs (which has been deleted) to your website on your iron sun theories, you are one post away from banishment. This is why I try to limit the topic, it invariable gets hijacked by the iron sun and electric universe people. – Anthony
If not, what does the “neutron star” theory assert they are made from?
mathman (08:55:34) wrote: “See any of several works by Stephen Hawking or Roger Penrose for more information about what is currently known about neutron stars, black holes, and stellar evolution.”
I’m sorry, but Hawking and Penrose’s theories are complete garbage.
James F. Evans (09:23:22) :
I’m sorry, but Hawking and Penrose’s theories are complete garbage.
Such a sorry statement really disqualifies you from any serious discussion. They may not be completely correct [if you can point out specific points and argue scientifically about them – e.g. whether information is lost in black holes], but such is real science: an approximation to reality as opposed to the know-all attitude of pseudo-science and fringe nuttiness.
Anthony,
I don’t see that this discussion is off topic at all. You made a post, it says a load of things that are questionable right from the off.
This is precisely the type of conversation that scientists should be having, in order to put competing views on the table. Your limit of the topic is censorship.
I am not an “electric universe person”, however I am angry that for 30 years no one told me that there was any viable alternative. I am now happy to discover the “iron sun” idea thanks to your attempt to censor it, since I had not heard of it before.
I am interested in the science and I happen to think that the electric ideas make a lot of sense. For example if a cosmic ray or cloud of gas were to move into the space where the pulsar is present, then the conductivity of the region would change and the output of the pulsar would suffer a transient variation in its period. I had never thought of this idea before, since I wasn’t aware of pulsars speeding up before reading this article. I was looking forward to someone explaining to me why this isn’t the case. But now you have banned any other EU people from working this through with me.
Frankly, on a site dedicated to the non-consensus I am a appalled.
Leif Svalgaard: Black Holes are a conjecture based upon a mathematical result, so building conjecture upon conjecture, within the theoretical space, when we are talking about a physical entity is moving in pretty shaky territory, and theoreticians have got so used to doing this, and calling it hard science, while there is no one to call their bluff.
So called confirming observations, are not confirming the Back Hole itself, but the conjecture nth removed. Methodologically speaking it is pretty open to the accusation of being a faery tale. This is why Mr Evans can write it off so easily.
If they published their ideas with a probabilistic evaluation of how likely it is, i.e being honest about the methodological weakness, calling their theories “thought experiments” rather than “science” then they would have more credibility. However they publish with an air of certainty and arrogance because “maths is the highest purest science after all”.
Have you ever met a graduate engineer with all the theory but absolutely no common sense, who doesn’t know what a left handed hammer is? I think that those of us who can see that theorists can be limited in the common sense department may be forgiven for being sceptical about their claims.
Keith (12:29:29) :
however I am angry that for 30 years no one told me that there was any viable alternative
That is precisely the issue. These are not viable alternatives. They are in the ‘not even wrong category’.
And there are websites dedicated to such fringe ideas. More of them, actually, than there are with real science.
Leif Svalgaard,
So according to you “the science is settled.”
Where have I heard that before?
Quote: Leif Svalgaard (14:56:38) :
“These are not viable alternatives.”
No, Leif, you are wrong.
You still know today what I thought I knew in 1960, before making measurements of isotopes and elements in meteorites, the Moon, the Earth’s mantle, the solar wind, Mars, Jupiter, and solar flares.
“What is” will not change to match your theory, so you may want to reexamine your theory.
That’s just the way it is,
Oliver K. Manuel
Former NASA PI for Apollo
Leif Svalgaard:
may I suggest that you find a case study where a theory is proposed, predicts an outcome, and that outcome is subsequently observed, in no uncertain terms.
Reading such a case gives you a very satisfactory feeling.
For example Humpreys proposed a model, in advance, of measurements that was able to predict the magnetic fields of uranus and other planets that were subsequently measured. How often does that happen? Wallace Thornhill’s predictions of Deep Impact, and Neptunes hot south pole, also give that satisfying feeling.
Remember that feeling, and then see if you get it each time you read a NASA press release with it’s on going song in which the chorus goes, “ooh we never expected this or that”.
keith (15:43:24) :
So according to you “the science is settled.”
Where have I heard that before?
you have heard it when you learned that the Earth is round, that mass and energy are equivalent [E=mc^2], that the Sun is 149,597,887.5 km distant on average, that the speed of light [uh-oh, this one might make some people gag] is 299 792 458 m/s, that the Earth is 4.54 billion years [another one to make some people gag], that an adult human has [should have] 32 teeth, that etc. etc.
Of course, the above assumes that you at least a modicum of education, if not, well, then all bets are off… You tell me.
keith (15:51:02) :
may I suggest that you find a case study where a theory is proposed, predicts an outcome, and that outcome is subsequently observed, in no uncertain terms.
Reading such a case gives you a very satisfactory feeling.
You are correct, that is very satisfying. Back in 1967 I observed some magnetic perturbations in the polar caps of the Earth [I was living in Greenland at the time] and hypothesized that these were related to the polarity of the interplanetary magnetic field. At that time it took several years before the spacecraft data was finally processed into ‘science data’. Based on my theory and data, we predicted what the interplanetary field would be seen to be when the data was finally processed. This paper describes the result: http://www.leif.org/EOS/JA080i025p03685.pdf As you can see the prediction was nicely verified [see the Figures], and, indeed that is a very good feeling.
Remember that feeling, and then see if you get it each time you read a NASA press release with it’s on going song in which the chorus goes, “ooh we never expected this or that”.
That song is most often pure PR as they have to justify their funding. Most of the stuff they announce is just confirmation of earlier theories often decades old. Now and then they observe something unexpected and new as is normal when you venture into unexplored territory.
Oliver K. Manuel (15:45:48) :
“These are not viable alternatives.”
No, Leif, you are wrong.
You still know today what I thought I knew in 1960
I thought we have over that ground often enough that we don’t need to hijack the thread once more.
> “you have heard it when you learned that the Earth is round”
Observed.
> That mass and energy are equivalent [E=mc^2]
I will leave that one, since that is one I have accepted by faith and haven’t yet questioned it much.
>that the Sun is 149,597,887.5 km distant on average
Observed.
> that the speed of light [uh-oh, this one might make some people gag] is 299 792 458 m/s,
I am not entirely convinced particularly since the nature of light is not very well explained. I am, like many, still waiting for an explanation which gives the “ah of course, its so simple”. I have been told that light behaves like both a wave and a particle, and I accepted it on faith because I was accepting most things that way. Yet there are many properties that remain unexplained such as the behaviour when polarized. The two slit experiment still defies deterministic explanation.
I do occasionally have random thoughts about the nature of light, for example, what if the speed of light was nearly infinite, but the speed of effect of light on the detector was limited. In this case it would look for all intents and purposes as if the speed of light was fixed, irrespective of relative velocities. I am likely showing my ignorance here with this idea, but there is a principle at stake here. Science makes progress by such “random thoughts”, you try things out to see if they go anywhere. To do this you have to put accepted wisdom on the shelf for a bit even if the hypothesis is a bit off the wall.
Some have suggested that the speed of light is changing even looking at historical measurements. Currently measurements using atomic clocks, will be constant, because any variation in c will be reciprocated by a change in planks constant.
We also need an explanation for the mechanism behind red-shifted light from quasars, which do not apparently fit the hubble law.
> that the Earth is 4.54 billion years [another one to make some people >gag],
Not observed, I wasn’t there.
It takes only one observation to challenge a theory. That observation is the fact that C-14 is found in diamonds and coal. Please I would like a convincing explanation for that.
> that an adult human has [should have] 32 teeth,
I can count them myself
> Of course, the above assumes that you at least a modicum of education,
> if not, well, then all bets are off… You tell me.
I have some of the required education, a degree in engineering, but I was also taught to think, I can also see where I am being been spoon fed.
Keith (19:11:58) :
> That mass and energy are equivalent [E=mc^2]
I will leave that one, since that is one I have accepted by faith and haven’t yet questioned it much.
Ask people in Hiroshima
> that the speed of light [uh-oh, this one might make some people gag] is 299 792 458 m/s,
I am not entirely convinced
Is observed in many different ways. and is actually used as the Definition of the meter, so the value is exact. The simplest way of observing the speed of light is the phenomenon of aberration. Just like rain seems to hit you harder in the front when you are moving, the position of stars and galaxies shifts because of the Earth’s movement in its orbit. The shift is 20.49552 arc seconds which for an orbital speed of 29783 m/s gives the speed of light as (180*3600 arcsecs)/20.49552*29783 = 299,733,050 m/s. Close enough as an estimate from the simple [inexact] formula given.
We also need an explanation for the mechanism behind red-shifted light from quasars, which do not apparently fit the hubble law.
Yes, they do to the extent that we can guess their distances [which is the difficulty here].
> that the Earth is 4.54 billion years [another one to make some people >gag],
Not observed, I wasn’t there.
Nonsense answer, you were not there for any of the other observations.
It takes only one observation to challenge a theory.
No. In the vast majority of cases if an observation does not fit a well-established theory [i.e. one that agrees with thousands of observations], then the first place to look is to the quality and interpretation of the observation.
That observation is the fact that C-14 is found in diamonds and coal. Please I would like a convincing explanation for that.
Fact? There is no such documented study [provide a link to the relevant papers]. These substances contain small amounts of nitrogen and nearby radioactive processes could produce minute amounts of 14C the same way cosmic rays do it in the atmosphere. But more to the point, I don’t know of any study of this, so provide a link [and not just to a creationist/young-earth site with no further links].
I can also see where I am being been spoon fed.
It seems necessary, at times.
gives the speed of light as (180*3600 arcsecs)/20.49552*29783 = 299,733,050 m/s.
Need a ‘pi’ in there: gives the speed of light as (180*3600/pi arcsecs)/20.49552*29783 = 299,733,050 m/s.
Quote: Keith (19:11:58) :
1. “> That mass and energy are equivalent [E=mc^2]
I will leave that one, since that is one I have accepted by faith and haven’t yet questioned it much.”
2.” > that the Earth is 4.54 billion years [another one to make some people >gag],
Not observed, I wasn’t there.”
3. “It takes only one observation to challenge a theory. That observation is the fact that C-14 is found in diamonds and coal. Please I would like a convincing explanation for that.”
Keith, I respect and admire your willingness to challenge dogma. Here are my responses to the above points:
1. We routinely observe (delta)E – (delta)mc^2 in nuclear reactions.
2. Claire Patterson first showed that Earth and iron meteorites formed about 4.55 billion years ago using Pb-Pb dating. This method does not require separate analysis of Pb and U isotopes because U-238 decays to Pb-206 (A = 4N + 2 series) and U-235 decays to Pb-207 (A = 4N + 3 series).
The method that Clair used assumes that Earth and iron meteorites had the same initial composition of Pb isotopes. The later discovery that the solar system formed out of chemically and isotopically heterogeneous material raised questions about the validity of Clair’s conclusion.
Subsequent findings that Earth and iron meteorites formed out of the same iron-rich region of the solar nebula lessened the likelihood of a major error.
3. I did not know that C-14 had been observed in diamonds. That would be a problem to explain, since the half-life of C-14 (~5,000 years) is much less than the age of the diamonds. Can you provide a reference?
With kind regards,
Oliver K. Manuel
Dr. Svalgaard, please give a physical description of a “singularity”.
C-14 is found many places it ‘should not’ be according to its half life, but basing the conclusion on half life alone, you do not get the full picture. There is also the material around the diamond, coal, whatever to consider. And it appears that this is the explanation for C14 where it ‘should not’ be. Not relevant to quasars at all, though.