The intensity of the sun’s million-mile-per-hour solar wind has dropped to its lowest levels since accurate records began half a century ago, scientists say.
Measurements of the cosmic blasts of radiation, ejected from the sun’s upper atmosphere, were made with the Ulysses spacecraft, a joint mission between NASA and the European Space Agency (ESA).
The solar wind “inflates a protective bubble, or heliosphere, around the solar system,” which protects the inner planets against the radiation from other stars, said Dave McComas, Ulysses’ solar wind principal investigator and senior executive director at the Southwest Research Institute in San Antonio, Texas.
“With the solar wind at an all-time low, there is an excellent chance the heliosphere will diminish in size and strength,” said Ed Smith, NASA’s Ulysses project scientist at the Jet Propulsion Laboratory in Pasadena, California.
“If that occurs, more galactic cosmic rays will make it into the inner part of our solar system,” added Smith.
The solar wind — a stream of charged particles ejected from the sun’s upper atmosphere at 1 million miles per hour — is significantly weaker, cooler and less dense than it has been in 50 years, according to new data from the NASA-European solar probe Ulysses.And for the first time in about a century, the sun went for two months this summer without sunspots, said NASA solar physicist David Hathaway. That record was broken Monday when a cluster of eight sunspots surfaced. Sunspots are temporary regions of high magnetic activity that from Earth appear to be black splotches.
The cause for the sun’s slight weakening seems to be a change in its magnetic flux, said Dave McComas of the Southwest Research Institute. Why it’s happening is a mystery, but it has fluctuated like this in the past.
Fewer sunspots means decreased solar winds. Decreased solar winds mean more cosmic rays penetrate the atmosphere. The increase in cosmic rays in the atmosphere increases cloud cover.
[Cosmic] rays, tiny charged particles that bombard all planets with varying frequency depending on solar wind intensity, may have height-dependent effects on our planet’s cloudiness. Previous research has proposed a link between cosmic rays and cloud cover, has not suggested the altitude dependence of the current study.
“A systematic change in global cloud cover will change the atmospheric heating profile,” Yu said. “In other words, the cosmic ray-induced global cloud changes could be the long-sought mechanism connecting solar and climate variability.”
The hypothesis, if confirmed, could also shed light on the Sun’s role in global warming. The amount of cosmic rays reaching Earth depends on solar winds, which vary in strength by space-weather conditions.
More cloud cover means less solar radiation reaches the surface of the earth and that, of course, means lower global temperatures.
Sunspots have been at a 100 year low. Solar winds are the lowest ever measured. It’s gonna get cold. Get ready.