December 23, 2006
ANITA over Antarctica
May 24, 2006
Voyager II heliopause & termination shock update
April 20, 2006
Betting on science?
Previously the gamblers had badly underestimated the chances of scientific answers to a number of interesting, outstanding questions. Of particular note is the now 4:1 odds on the discovery of the source of the highest energy cosmic rays.
April 6, 2006
Solar system abundance oxygen may well be more complicated than previously thought
April 3, 2006
Carlo De Marzo Obituary
He passed away back in September, but his obituary just appeared in the CERN Courier. He was involved with MACRO, Antares, PAMELA, and NEMO.
February 13, 2006
FYI: Marty Israel
From Jason Link:
"I just got off the phone with Bob [Binns] about Marty Israel. He was administering a test to his class when he experienced severe chest pains. He went down to the main office to have an ambulance bring him to Barnes Hospital. It appears he suffered a heart attack, but due in part to his quick response in getting to the hospital, the doctors believe he is going to be fine. He is now in the intensive care cardiac ward and will probably remain there for a few days before transferring to another room in the hospital for some more surveillance."
From Bob Binns:
"Many of you know that Marty had a heart attack yesterday. He was in class around 1:15 pm when he experienced severe chest pains. An ambulance was called and he was rushed to Barnes Hospital and his friend, Sandor Kovacs, who is the head of cardiology, got him treatment very quickly. He had blockage of an artery and two stints were placed in the artery. I saw him around 3:45pm after the procedure. He was conscious and was concerned about a talk that he was supposed to give to boy scouts last night. Sandor told me that the prognosis was very good for recovery. There was some damage to the heart muscle but it was not extensive. I understand from Cliff Will that Marty experienced some additional heart pains last night, but I do not know the significance of that. As of last night the expectation was that he would be in intensive care for 1-2 days and then move to another floor for another 1-2 days. I will keep you informed as I know more."
Again from Bob, refering to the night of 2/13:
"Marty had a rough night last night with chest pains during at least part of the time. This morning they did another heart catheterization procedure to see if there were additional problems. They did not see any new problems. I think that Marty was encouraged. Margaret flew back from San Diego and arrived after midnight last night. Margaret and Elisa were with him when I left the hospital. I relayed to him your many thoughts of concern, prayers, and best wishes and he appreciated them all."
From Bob Binns again, on the 15th:
"Marty called a few minutes ago and told me that he had not had any additional chest pains since yesterday morning. Furthermore, yesterday (it must have been in the afternoon or evening) his doctor released him from ICU. He is still in the ICU, but only because there is not yet a bed available in what I think is a Cardiac care unit at Barnes. He was very upbeat and sounded good."
February 9, 2006
HESS press release
Gamma-ray Afterglow from Galactic Centre Gas Clouds reveals Pre-Historic Particle Accelerator
Astrophysicists using the H.E.S.S. gamma-ray telescopes, in Namibia, have announced the detection of very-high-energy gamma rays from huge gas clouds known to pervade the centre of our Galaxy. These gamma rays are expected to result from the even more energetic cosmic-ray particles, which permeate our entire Galaxy, crashing into the clouds. However, precise measurements of the intensity and energies of these gamma rays, thanks to this most sensitive instrument in the world in this energy range, further show that in the central region of our Galaxy these cosmic-ray particles are typically more energetic than those we measure falling on the Earth's atmosphere. Possible explanations for this energisation of the cosmic rays near the heart of our Galaxy include the echo of a Supernova which exploded some hundred centuries beforehand or a burst of particle acceleration by the supermassive black hole at the very centre of our galaxy.
The discovery: In a recent publication in Nature magazine, the international H.E.S.S. collaboration reported the discovery of gamma-ray emission from a complex of gas clouds near the centre of our own Milky-Way Galaxy. These giant clouds of hydrogen gas encompass an amount of gas equivalent to 50 million times the mass of the sun. With the highly sensitive H.E.S.S. gamma-ray telescopes, it is possible for the first time to show that these clouds are glowing in very-high-energy gamma rays.
The issue: One key issue in our understanding of cosmic rays is their distribution in space. Do they permeate the entire Galaxy uniformly, or do their density and distribution in energy vary depending on one's location in the Galaxy (for example due to the proximity of cosmic particle accelerators)? We can only take direct measurements of cosmic rays within our solar system, located about 25,000 light years from the centre of the Galaxy. However, a subterfuge allows astrophysicists to investigate cosmic rays elsewhere in the Galaxy: when a cosmic-ray particle collides with an interstellar gas particle, gamma rays are produced.
The gamma-ray / cosmic-ray link: The central part of our Galaxy is a complex zoo, containing examples of every type of exotic object known to astronomers, such as the remnants of supernova explosions and a super-massive black hole. It also contains huge quantities of interstellar gas, which tends to clump in clouds. If gamma rays are detected from the direction of such a gas cloud, scientists can infer the density of cosmic rays at the location of the cloud. The intensity and distribution in energy of these gamma rays reflects that of the cosmic rays.
At low energies, around 100 Million electronVolts (man-made accelerators reach energies up to 1,000,000 Million electronVolts), this technique has been used by the EGRET satellite to map cosmic rays in our Galaxy. At really high energies - the true domain of cosmic-ray accelerators - no instrument was so far sensitive enough to "see" interstellar gas clouds shining in very-high-energy gamma rays. H.E.S.S. has for the first time demonstrated the presence of cosmic rays in this central region of our Galaxy.
The surprise: The H.E.S.S. data show that the density of cosmic rays exceeds that in the solar neighbourhood by a significant factor. Interestingly, this difference increases as we go up in energy, which implies that the cosmic rays have been recently accelerated. So, these data hint that the clouds are illuminated by a nearby cosmic-ray accelerator, which was active over the last ten thousand years. Candidates for such accelerators are a gigantic stellar explosion which apparently went off near the heart of our Galaxy in "recent" history (Chandra press release ), another possible acceleration site is the super-massive black hole at the centre of the Galaxy. Jim Hinton, one of the scientists involved in the discovery, concludes "This is only the first step. We are of course continuing to point our telescopes at the centre of the Galaxy, and will work hard to pinpoint the exact acceleration site - I'm sure that there are further exciting discoveries to come"
The collaboration: The High Energy Stereoscopic System (H.E.S.S.) team consists of scientists from Germany, France, the UK, the Czech Republic, Ireland, Armenia, South Africa and Namibia.
The detector: The results were obtained using the High Energy Stereoscopic System (H.E.S.S.) telescopes in Namibia, in South-West Africa. This system of four 13 m diameter telescopes is currently the most sensitive detector of very high energy gamma rays. These are absorbed in the atmosphere, where they give a short-lived shower of particles. The H.E.S.S. telescopes detect the faint, short flashes of blueish light which these particles emit (named Cherenkov light, lasting a few billionths of a second), collecting the light with big mirrors which reflect onto extremely sensitive cameras. Each image gives the position on the sky of a single gamma-ray photon, and the amount of light collected gives the energy of the initial gamma ray. Building up the images photon by photon allows H.E.S.S. to create maps of astronomical objects as they appear in gamma rays.
The H.E.S.S. telescope array represent a multi-year construction effort by an international team of more than 100 scientists and engineers. The instrument was inaugurated in September 2004 by the Namibian Prime Minister, Theo-Ben Guirab, and its first data have already resulted in a number of important discoveries, including the first astronomical image of a supernova shock wave at the highest gamma-ray energies.
Dr. Jim Hinton
Max-Planck-Institut fuer Kernphysik
Tel +49 6221 516279
University of Heidelberg
Tel +49 6221 541737
Prof. Werner Hofmann
Max-Planck-Institut fuer Kernphysik
Tel +49 6221 516330
February 8, 2006
NASA science funding and the shuttle
February 6, 2006
Cold dark matter might not be so cold
In what looks to be the first measurement of the temperature of the dark matter, a result of about 10k K comes as a bit of a surprise. Good popular science coverage at the BBC!
Meet the censor at NASA HQ
As mentioned in the popular news coverage, NASA public affairs officer George Deutsch sent out a memo insisting that the word "theory" be included with every mention of the Big Bang.
His memo reads:
"The Big Bang is "not proven fact; it is opinion," Mr. Deutsch wrote, adding, "It is not NASA's place, nor should it be to make a declaration such as this about the existence of the universe that discounts intelligent design by a creator." "This is more than a science issue, it is a religious issue. And I would hate to think that young people would only be getting one-half of this debate from NASA. That would mean we had failed to properly educate the very people who rely on us for factual information the most."
Wow! Read what else Mr. Deutsch has to say here on salon's blogs. So, we have a 24 year old journalism student from Texas A&M censoring NASA scientists. What qualifications does Deutsch have? He appears to have been an intern in the Bush-Cheney reelection campaign.