For more than 50 years, the Sun has not seen such a small number of "spots" as this year. For this reason, scientists even called 2008 the "whitest year" of the space age
Something similar happened in 1954, in other words, three years before the launch of the first artificial Earth satellite. So yesterday there was not a single spot on the surface of the Sun, and this situation has been observed for more than 200 days since the beginning of this year (in 1954 there were 241 days without spots on the Sun). But something else is also happening on the Sun. NASA scientists have reported that the stellar wind is losing strength. “The average pressure has dropped by 20% compared to the mid-90s. This is the lowest pressure since monitoring began, in other words, in 50 years,”said Dave McComas of the Southwest Research Institute in San Antonio, USA. And that is not all. "Over the past 10-12 years, the background magnetic field has weakened by 30%," added Eric Posner of NASA.
Let's try to figure it out a bit. Sunspots are areas where temperatures are almost 1,000 degrees lower than adjacent areas of the Sun's surface, which is why they appear darker, although their temperature reaches 5,000 degrees Celsius. These spots are associated with complex magnetic phenomena occurring on the surface of the Sun. Over an 11-year cycle, their number ranges from minimum to maximum. The last minimum was reached last year, so it was believed that 2008 would be the year during which the number of sunspots increased, but this did not happen.
What are the consequences of all this? So far, according to scientists, it is premature to draw any conclusions. There were years when there were no spots on the Sun for 200-300 days, and this did not have any consequences, but some scientists are looking a little further. David Hathaway, a solar physicist at NASA, recalls that there was an unprecedented minimum in solar activity between 1645 and 1715, and during this period the Earth experienced a "little ice age", a period with particularly cold winters.
The decrease in the strength of the solar wind is even more mysterious. The solar wind is a stream of particles (high-energy protons) ejected from the outer part of a star's atmosphere as a result of solar storms. A sharp decrease in the strength of this stream was recorded by the probe of the European Space Agency and NASA Ulysses (which ceased to exist a few months ago), this probe orbited the Sun's pole three times. The instruments on board the probe showed that the recorded pressure drop was associated with a 13% drop in temperature from the average. But what is unusual about this phenomenon? "It is rather difficult to answer this question, because we have been monitoring the solar wind since the 60s: this is a fairly short period when compared to the age of the Sun, which is approximately 5 billion years old."- said Posner.
But what are the consequences? “Changes in the intensity of the solar wind have an impact on the entire solar system. This system is located in a huge bubble called the heliosphere, created precisely by the solar wind. It protects us from cosmic radiation from the Universe,”emphasizes Posner. High-energy particles from black holes or from exploding stars try to enter the solar system, but it is the heliosphere that blocks them. Is there any danger to the Earth? “No,” the physicist continues, “because our atmosphere and the Earth's magnetic fields serve as reliable shields. Astronauts on long missions to Mars or long missions on the moon could face serious problems. But so far there is no reason for undue concern."
