Have you ever been hit by high energy particles from above? Surely, since it happens all the time. But the situation with cosmic rays is getting worse. Cosmic rays bombarding the Earth … they are all bad and only gets worse. This is the conclusion in a recently published article in the research journal Space Weather, which shows that radiation from space is dangerous and amplifies faster than previously thought.
The story begins four years ago, when Schwadron and his colleagues first raised the alarm over cosmic rays. Analyzing data from the CRATER space telescope - the main purpose of which is to assess the harmful effects of cosmic rays and solar radiation on biological objects, located on board LRO - NASA's automatic interplanetary station, an artificial moon satellite, they found that cosmic rays in the Earth-Moon system reach a level never seen before in the space age. And in their opinion, the deterioration of the radiation situation now represents a potential danger to astronauts, limiting their time spent in space.
These numbers, from their original 2014 article, show the number of days that a 30-year-old male astronaut flying in a 10 g / cm2 aluminum-shielded spacecraft can withstand the radiation limits set by NASA guidelines:
Cosmic rays in the Earth-Moon system have reached levels never seen before in the space age, and the trend is only getting worse.
In the 1990s, an astronaut could spend 1,000 days in interplanetary space. In 2014… only 700 days. “These are huge changes,” says Schwadron.
Galactic cosmic rays come from outside the solar system. They are a mixture of high-energy charged particles and subatomic particles accelerated toward Earth by supernova explosions and other explosive events in space. Our first line of defense is the Sun: the solar magnetic field and solar wind combine to create a porous "shield" that reflects cosmic rays trying to penetrate the solar system. The sun's defensiveness is strongest during solar maximum and weakest during solar minimum - hence the graph associated with the 11-year cycle (above).
The problem is that, as the authors note in their new article, the shield is weakening: “Over the past decade, the solar wind has shown low density, and the strength of the magnetic field is also weakening, which are strange anomalies that have never been observed in the space age. As a result of this surprisingly weak solar activity, we also saw the highest fluxes of cosmic rays."
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Back in 2014, Schwadron and colleagues used a leading solar activity model to predict how bad cosmic rays would behave during the next solar minimum, which is expected in 2019-2020. “Our previous work involved increasing the dose rate by 20% from one solar minimum to the next,” says Schwadron. “In fact, we now see that the actual radiation doses observed by CRATER over the past 4 years are 10% higher than forecasted, indicating that the radiation situation is worsening even faster than we expected.” In this graph, the bright green data points show the most recent exceedances:
But even on Earth this deterioration is felt
Spaceweather.com and Earth to Sky Calculus have launched space weather balloons into the stratosphere almost every week since 2015. Sensors aboard these balloons show a 13% increase in radiation (X-rays and gamma rays) entering our planet's atmosphere:
The X-rays and gamma rays detected by these balloons are "secondary cosmic rays" created by the collapse of the primary cosmic rays in the upper atmosphere of the Earth. The energy range of the sensors is from 10 keV to 20 MeV, similar to the range of medical X-ray machines and airport security scanners.
How does this affect us?
Cosmic rays hit commercial airlines, dosing passengers and flight crews so hard that pilots are classified by the International Commission on Radiological Protection as occupationally exposed workers. Some studies show that cosmic rays can seed clouds and cause lightning, and potentially affect weather and climate. In addition, there are studies linking cosmic rays to health in the general population.
This graph displays radiation measurements not only in the stratosphere, but also at aviation heights. Shown in relation to sea level. For example, we see that on an airplane flying at an altitude of 25,000 feet, passengers receive doses 10 times higher than sea level. At 40,000 feet, the dose approaches 50x. Via Spaceweather.
Why is the power of cosmic rays increasing?
The main reason is the Sun. Coronal mass ejections (CMEs) sweep away cosmic rays as they pass Earth. During solar maximum, CMEs are abundant and this affects cosmic rays. Now, however, the solar cycle is approaching a minimum, allowing cosmic rays to attack Earth with full force. Another important reason is the weakening of the Earth's magnetic field, which protects us from cosmic radiation.
One thing is clear, cosmic rays will only intensify and intensify even more in the coming years, as the Sun plunges into what may be the deepest solar minimum in more than a century.
