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The Jury Is In: Exploding Stars Really do Pelt us With Cosmic Rays

The rim of RCW 86. Credit: ESO/E. Helder & NASA/Chandra

The rim of RCW 86. Credit: ESO/E. Helder & NASA/Chandra

Mmm, pretty … and a tad menacing, at least in its explosive past. This is RCW 86, part of a stellar remnant whose explosion was recorded in 185 AD. By studying the remnant in detail, a team of astronomers has been able to nail down the source of cosmic rays that bombard Earth.

During the Apollo flights 40 years ago,  astronauts reported seeing odd flashes of light, visible even with their eyes closed. We have since learned that the cause was cosmic rays — extremely energetic particles from outside the Solar System arriving at the Earth, and constantly bombarding its atmosphere. Once they reach Earth, they still have enough energy to cause glitches in electronic components.

Galactic cosmic rays come from sources inside our home galaxy, the Milky Way, and consist mostly of protons moving at close to the speed of light, the “ultimate speed limit” in the Universe. These protons have been accelerated to energies exceeding by far the energies that even CERN’s Large Hadron Collider will be able to achieve.

“It has long been thought that the super-accelerators that produce these cosmic rays in the Milky Way are the expanding envelopes created by exploded stars, but our observations reveal the smoking gun that proves it,” says Eveline Helder from Utrecht University in the Netherlands, the first author of the new study in this week’s Science Express.

“You could even say that we have now confirmed the caliber of the gun used to accelerate cosmic rays to their tremendous energies,” adds collaborator Jacco Vink, also from the Astronomical Institute Utrecht.

For the first time Helder, Vink and colleagues have come up with a measurement that solves the long-standing astronomical quandary of whether or not stellar explosions produce enough accelerated particles to explain the number of cosmic rays that hit the Earth’s atmosphere. The team’s study indicates that they indeed do and directly tells us how much energy is removed from the shocked gas in the stellar explosion and used to accelerate particles.

“When a star explodes in what we call a supernova a large part of the explosion energy is used for accelerating some particles up to extremely high energies,” says Helder. “The energy that is used for particle acceleration is at the expense of heating the gas, which is therefore much colder than theory predicts.”

The researchers looked at the remnant of a star that exploded in AD 185, as recorded by Chinese astronomers. RCW 86, is located about 8,200 light-years away towards the constellation of Circinus (the Drawing Compass). It is probably the oldest record of the explosion of a star.

Using ESO’s Very Large Telescope, the team measured the temperature of the gas right behind the shock wave created by the stellar explosion. They measured the speed of the shock wave as well, using images taken with NASA’s X-ray Observatory Chandra three years apart. They found it to be moving AT between 1 and 3 percent the speed of light.

The temperature of the gas turned out to be 30 million degrees Celsius. This is quite hot compared to everyday standards, but much lower than expected, given the measured shock wave’s velocity. This should have heated the gas up to at least half a billion degrees.

“The missing energy is what drives the cosmic rays,” concludes Vink.

More about the lead image: North is toward the top right and east to the top left. The image is about 6 arc minutes across. Credit: ESO/E. Helder & NASA/Chandra

Source: ESO

Comments on this entry are closed.

  • DrFlimmer June 25, 2009, 12:09 PM

    Look, those beautiful filaments…. err… shock waves!

    Sorry, I couldn’t resist.

    Isn’t it great that we can really achieve such things as where cosmic rays come from? At least where those “not-so-high-energetic” CRs are coming from (those that are lower energetic than the knee).

    For the ultra-high energetic particles with up tp 10^21eV the source still needs to be found. Most likely jets of AGN are responsible for them, so they are most likely extra-galactic. It is really amazing that these ultar-CRs are mostly not influenced by magnetic fields – they are just too fast! Incredible…

  • Lawrence B. Crowell June 25, 2009, 8:03 PM

    I am going to have to look this up some. I am intrigued by the possible mechanism behind this. This implies from a thermodynamic perspective that supernovae are highly efficient. They send a high percentage of their energy out in the form of kinetic energy of particles and less in the form of heat.

    Lawrence B. Crowell

  • Torbjorn Larsson OM June 26, 2009, 8:58 AM

    Continuing this line of questioning, aren’t they surprisingly efficient at nucleosynthesis as well?

    Apparently they aren’t your ordinary explosions, I wonder why?

    What is the influence from the compressing magnetic fields, are they responsible for some type of magnetic bottle/inertia fusion effect? Intriguing indeed.

    [The nucleosynthesis part is heat and inertia at a layman's guess, older models should account for that already surely, and probably no need for EM effects. But the acceleration/cooling stuff is curious.]

    Cue PU creationists in 1… 2… :-o]

  • wjwbudro June 26, 2009, 2:04 PM

    Way off this topic but, I have put off asking for too long….
    Fraser, where off earth did you find this latest sponsor? lol

  • Anaconda June 27, 2009, 12:23 AM

    @ Torbjorn Larsson OM:

    Funny you should say “creationists” because you can’t get any more “creationist” than the “big bang”:

    Something out of nothing.

    Or as somebody said on this website: “The big bang started out smaller than an atom.

    Lots of luck.

  • Lawrence B. Crowell June 28, 2009, 6:00 AM

    The inflationary episode of the big bang is a manifestation of quantum fluctuations. There is no “special creation” per se which is invoked.

    As with the black hole argument it becomes clear that you are attempting to object to something of which you have minimal or no understanding of.

  • Anaconda June 28, 2009, 4:24 PM

    @ Lawrence B. Crowell:

    You’re dreaming :-)

    Nobody knows how the Universe started or if it started.

    It’s all just a big guessing game.

  • IVAN3MAN June 30, 2009, 9:32 AM

    Anaconda:

    You’re dreaming | Nobody knows how the Universe started or if it started. | It’s all just a big guessing game.

    Guessing game?! Dreaming?! It’s these “Electric Universe” proponents who are the real dreamers! They are not interested in real science; they are a fanatical religion, like Scientology, and here is the latest video from the Thunder[bollocks].info group which confirms that fact: http://www.youtube.com/watch?v=vyhKl-XywtY (WARNING: Before viewing, put aside any beverages, otherwise you will choke with laughter!)

    Note that, in the second half of that video, the term “bull” is often mentioned in reference to some mythical creature. Well, the term “bull” is half right, but it’s missing the obvious second syllable! ;-)

    Furthermore, Anaconda has been an active member of the Thunder[bollocks].info group since last April.

    Furthermore, if your brain has gone numb after watching that video, then I apologize for inflicting it on you.

  • Anaconda June 30, 2009, 1:23 PM

    @ Ivan3Man:

    Yes, guessing game.

    Ivan, you’re running around like Richard Pryor — your hair’s on fire :-)

    And here is a fly for your “big bang” ointment:

    Observation number correlation in WMAP data

    http://arxiv.org/abs/0905.0075

    “Our results indicate that, for precision cosmology study based on WMAP observations, the observation effect on released WMAP temperature maps has to be further carefully studied.”

    What the paper goes on to state is that the data doesn’t work out for the so-called “big bang”.

    “The new paper, Observation number correlation in WMAP data By Ti-Pei Li et al, which has been accepted by MNRAS, shows that a spurious apparent temperature is introduced into the map of the CMB by the WMAP team’s analyses. As a result, the conclusions based on this analysis, including the widely-publicized supposed agreement with some predictions of the dominant LCDM cosmology, are thrown into doubt.”

    Just another day in paradise for “modern” astronomy.

    Ivan, you better carry around a bucket of water because Astronomy has all kinds of wild fires going on :-)

  • IVAN3MAN July 1, 2009, 9:08 AM

    @ Anaconda,

    Where the bloody hell does it state in the paper that you’ve linked to, “[...] As a result, the conclusions based on this analysis, including the widely-publicized supposed agreement with some predictions of the dominant LCDM cosmology, are thrown into doubt”?!

    I used the keywords “spurious” and “doubt” to search the PDF file, and I found absolutely nothing at all that matches your alleged quote. You simply pulled those alleged quotes out of your ass, didn’t you, Anaconda?

    I’ve said this before on the other thread and I’ll say it again here: You are a fraud, a charlatan, and a goddamn sophist rolled into one. You are also the equivalent of an academic arsonist, who is so bloody envious of the achievements of other men (and women), that the only way you know of compensating for your academic inadequacies is to destroy the works of others. Schweinehund!

  • DrFlimmer July 1, 2009, 9:35 AM

    What the paper goes on to state is that the data doesn’t work out for the so-called “big bang”.

    I’ve read the whole paper and found nothing like this statement! As I understand the paper it is just saying that “unexpected anomalys” can be explained by instrumentation and observation bias. This is probably good.
    But there is good news on the horizon: The recently launched Planck satallite works differently than WMAP and is less effected by such bias. Then we will know.

    So far, there is no crises in BB. WMAP still confirms the CMB and the standard model. Planck will definitly reveal what was going on in the beginning.

  • IVAN3MAN July 2, 2009, 7:45 AM

    @ DrFlimmer,

    It appears that paper was misinterpreted by none other than Eric J. (Jackass) Lerner, who wrote the book The Big Bang Never Happened, and Anaconda was quoting Eric’s ‘opinion’ of the findings of that paper rather than actually facts.

  • IVAN3MAN July 2, 2009, 7:53 AM

    Err… “actually” was meant to be: actual.

    (Grumble… no edit facility… grumble.) :|

  • DrFlimmer July 2, 2009, 12:33 PM

    I wondered how Anaconda would come to such a paper. This clearifys a lot. Well, well….

  • IVAN3MAN July 2, 2009, 2:52 PM

    @ DrFlimmer,

    Yeah, I also wondered where Anaconda got that paper from. I could not believe that he has so much time on his hands to trawl through astronomical papers in order to cherry-pick a few articles that allegedly support EU/PC hypotheses, so I figured that he must have got the tip-off from Thunder[bollocks].info, and, sure enough, I was right; he found out about that paper from someone called “D_Archer” here:
    thunderbolts.info/forum/phpBB3/viewtopic.php?f=3&t=2025

    Anaconda has been a member of that bloody outfit since last April.

  • Anaconda July 5, 2009, 5:45 PM

    It doesn’t matter where I gained knowledge of the paper, does it, what matters is the content of the paper.

    Yes, the unidentifed quote is from Lerner.

    But the other quote is from the paper, itself:

    “Our results indicate that, for precision cosmology study based on WMAP observations, the observation effect on released WMAP temperature maps has to be further carefully studied.”

    I suggest, “further carefully studied”, means the authors found errors in analysis of others who interpreted the WMAP.

  • DrFlimmer July 6, 2009, 10:39 AM

    No. They found that the “anisotropies” between north and south are probably due to problems with the instrument and the analysis. They do not question any fundamental cosmological model based upon WMAP.

    I suggest, you should read papers next time and do not interprete the abstracts. I have told you before that this could lead to misunderstandings concerning the content of the paper.

    Here is the last chapter of the paper:

    4 DISCUSSION

    Unexplained large scale anomalies, e.g. the orientation of largescale patterns in respect to the ecliptic frame, the north-south asymmetry of temperature fluctuation power etc, have detected in WMAP data. Their origin has long puzzled scientists. Several radical explanations with an anisotropic cosmology have already been proposed. However, it is, in particular, hard to imagine that there exists a special direction related to the ecliptic or Galactic plane in the early universe. In this work, we show that the large-scale features of the WMAP observation number map and observation number fluctuation distribution are very similar to the large-scale non-Gaussian modulation feature in released WMAP temperature map (§2), and find that significant correlation between pixel temperature and observation number exists inWMAP data (§3.1), such correlation can be produced by the systematic effect of WMAP instrument and observation imbalances on temperature maps (§3.2). The detected observation number correlation should contribute, at least partly, to the apparent similarity between the large-scale features of the WMAP observation exposure and temperature maps, and hopefully provide a natural way to explain some large-scale anomalies in released WMAP temperature maps.

    Inhomogeneity of observation numbers used in WMAP mapmaking is emerged at different sky scales, which should generate systematic errors in WMAP temperature maps in a wide range of angular scale through the significant t-N correlation revealed in this work. To limit systematic artifacts, a large amount works have been performed by the WMAP team. Due to the differential nature ofWMAP observations, it is a difficult task. As an example, though the effect of input transmission imbalance from radiometer nonidealities has been noticed, calibrated and modified by the WMAP team (Jarosik et al. 2003; Jarosik et al. 2007), we still find remarkably systematic dependence of temperature vs. observation number difference between the two horns residual in released WMAP maps. As shown in §3.22, hotspots in the sky can distort recovered temperatures of pixels on large part of the sky with a complicated way. It has to be pointed out that using Eq. 10 with a constant compensation factor to correct the effect of horn imbalance is just to roughly estimate the average magnitude of differential imbalance distortion. What shown in Fig. 4 is only on the meaning of the average. More works have to be done to find a proper approach to modify the effect of imbalance differential observation to recover a corrected temperature map.

    The real accuracy of cosmology parameters is the most important issue for high precision cosmology. Systematical temperature errors and structured noise fluctuations existed in CMB maps will certainly distort the angular power spectrum and the best-fit cosmology parameters as well. It is obviously needed to further study the errors inWMAP temperature and noise fluctuation maps caused by the observation inhomogeneity and imbalance. The systematic distortions detected by us in released WMAP maps come from the WMAP’s differential nature. The next CMB mission Planck is designed to measure the CMB anisotropy with completely different mode and expected to be unaffected by such kind of distortions.

  • IVAN3MAN July 6, 2009, 12:56 PM

    I am in total agreement DrFlimmer. You cannot deduce something from a mere abstract of a scientific paper.

    An abstract is like a movie trailer: it gives you the ‘feel’ of what the movie is about, but without revealing the essential plot; for that, you have to see the movie in its entirety.

  • Nereid July 6, 2009, 2:50 PM

    It doesn’t matter where I gained knowledge of the paper, does it, what matters is the content of the paper.

    Yes, the unidentifed quote is from Lerner.

    Actually, it matters a very great deal.

    At the very least, without proper attribution, no one can easily check a) whether what you quoted was what the author actually wrote (e.g. OilIsMastery/Total Science’s comments include several quotes that were, in fact, wrong, IIRC), and b) what the context of the quoted words is.

    Now I will acknowledge that your own behaviour – available for all to read – would seem to suggest that these things are trivial to you, perhaps even so insignificant that you don’t even notice them (after all, they are, in comparison with your blatantly demonstrated dishonesty and lack of integrity), but not everyone who comments here has the same abysmal standards of intellectual honesty as you.

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