Tag Archives: cosmic rays

Solar minimum to limit interplanetary manned flights?

A new study suggests that the increased cosmic radiation reaching the inner solar system because of the Sun’s weak sunspot activity will increase the exposure to dangerous radiation levels for interplanetary astronauts, thus limiting mission lengths to about one year.

The new research finds that, during periods of low solar activity, a 30-year-old astronaut can spend roughly one year in space—just enough time to get to Mars and back—before the constant bombardment by cosmic rays pushes the risk of radiation-induced cancer above current exposure limits.

If the sun’s activity continues to weaken as many scientists predict, the number of days humans could spend in deep space before reaching their exposure limit could decrease by about 20 percent, making future crewed space flight more dangerous, according to the new study accepted for publication in Space Weather, a journal of the American Geophysical Union.

The numbers were worse for women, whose exposure would become dangerous in only 300 days, according to the study.

A source for the most powerful cosmic rays?

Astronomers think they have discovered a region in the sky, within or near the Milky Way, which might be the source of the most energetic cosmic rays

Nobody knows how ultra–high-energy cosmic rays—mainly protons or heavier atomic nuclei—acquire energies millions of times higher than have been achieved with humanmade particle accelerators. (Physicists dubbed one of the first ones observed the “Oh-My-God particle.”) Lower energy cosmic rays are thought to spring from the lingering remnants of stellar explosions called supernovas. But such clouds are far too small to produce the highest energy cosmic rays. Instead, theorists generally expect that the most energetic cosmic rays rev up over millions of years in unidentified accelerators the size of galaxies.

The Telescope Array aims to help solve that mystery. When a high-energy cosmic array strikes the atmosphere, it disappears in an avalanche of lower energy particles. Those particles trigger the detectors in the array, enabling researchers to deduce the direction and energy of the original cosmic ray. From 2008 to 2013, researchers spotted 72 cosmic rays with energies above 57 exaelectron volts—15 million times the highest energy achieved with a particle accelerator. And 19 of them appear to cluster in a hotspot in the sky about 20° in radius, as Hiroyuki Sagawa, a co-representative for the Telescope Array team from the University of Tokyo, reported today in a press conference at the university. [emphasis mine]

The low number of detections, 19 out of 72 total, that seem to come from this wide 20 degree region, suggests that this report falls most certainly under the heading of “the uncertainty of science.” I would not be surprised at all if this conclusion does not stand up after further research.

Nonetheless, the article is worth reading because it outlines nicely this astronomical mystery. Something out there accelerates these particles to these high energies, and astronomers do not yet know what that something is.

A new study suggests that the variation of the cosmic ray flux during the solar cycle has little influence on the climate.

The uncertainty of science: A new study suggests that the variation of the cosmic ray flux during the solar cycle has little influence on the climate.

The study seems statistical in nature, which leaves me skeptical. Nonetheless, the link between cosmic rays and climate change remains tenuous, with only one study at CERN providing any evidence that cosmic rays might have an influence.

Scientists now believe they have found evidence proving that the unknown origin of cosmic rays are supernova explosions.

Scientists now believe they have found evidence proving that the unknown origin of cosmic rays are supernova explosions.

This has been one of astronomy’s longest outstanding mysteries: What produces the interstellar cosmic rays that come from outside our solar system?

New data from a neutrino telescope in Antarctica had found that cosmic rays don’t come from gamma ray bursts, as had been believed by astronomers.

The uncertainty of science: New data from a neutrino telescope in Antarctica has found that cosmic rays don’t come from gamma ray bursts, as had been believed by astronomers. You can read the paper here. [pdf]

Which means that astronomers at this moment have no idea what produces these high energy cosmic rays.

If there is water ice on the Moon, scientists have found that the bombardment from interstellar cosmic rays has likely caused chemical reactions that “can create complex carbon chains similar to those that help form the foundations of biological structures.”

Life stranger than science fiction: If there is water ice on the Moon, scientists have found that the bombardment from interstellar cosmic rays has likely caused chemical reactions that “can create complex carbon chains similar to those that help form the foundations of biological structures.”

“everything went completely crazy. . . . It turned out it was very, very sensitive to say these things already at that time.”

“Everything went completely crazy. . . . It turned out it was very, very sensitive to say these things already at that time.”

The sun, climate change, and censorship

The chief of CERN has prohibited its scientists from drawing any conclusions from a major experiment that appears to prove that solar activity and the resulting ebb and flow of cosmic rays has a direct effect on the climate.

Two points:

First, the results described provide strong evidence that the sun is a much more important component in climate change than any climate model has previously predicted. These results could help explain the Little Ice Age, which took place around 1700 at exactly the same time the sun became very quiet and stopped producing sunspots for decades. They could explain the Medieval Warm Period around 1000 AD, when cosmic ray activity declined (which also suggests the sun become more active) and the earth apparently warmed. And they might very well even explain the recent cooling during the past decade, which also took place during a period of solar inactivity and a comparable increase in cosmic ray activity.
» Read more