Effects Of The Solar Wind
The wind speed of a devastating Category 5 hurricane can top over 150 miles per hour (241km/hour.) Now imagine another kind of wind with an average speed of 0.87 million miles per hour (1.4 million km/hour.)
Welcome to the wind that begins in our Sun and doesn't stop until after it reaches the edge of the heliosphere: the solar wind.
The corona is the Sun's inner atmosphere - the brightness that can be seen surrounding an eclipsed Sun - and home to the continually expanding solar wind. Right now, the Parker Solar Probe - launched in 2018, is orbiting the Sun and will get as close as 3.83 million miles (6.16 million km) of the Sun's surface. Parker is gathering new data about the solar particles and magnetic fields that comprise the solar wind. More specifically, two of its main goals are to examine the energy that heats the corona and speeds up the solar wind, and determine the structure of the wind's magnetic fields.
While many theories describe the solar wind's history, this is what we do know: The solar wind impacting Earth's magnetosphere is responsible for triggering those majestic auroras typically seen at locations close to our north and south poles. In some cases it can also set off space weather storms that disrupt everything from our satellites in space, to ship communications on our oceans, to power grids on land.
To say in more detail , how the solar wind disrupts our magnetosphere: As the wind flows toward Earth, it carries with it the Sun's magnetic field. It moves very fast, then smacks right into Earth's magnetic field. The blow causes a shock to our magnetic protection, which can result in turbulence.
There is another reason to study the solar wind and its properties - the solar wind is part of a larger space weather system that can affect astronauts and technology. We not only have to ensure our astronauts are protected from the harmful effects of radiation.
We have to protect our equipment too. So, we've already found aluminum to be a good shield to protect our crafts from many energetic particles. But there are also faster particles that travel at 80% of the speed of light, which can cause havoc with parts of a spacecraft. They can smash into and damage solar panels, disrupt electronics, or affect electric currents that flow along power grids.
So, we're currently conducting tests with small pieces of technology to study how well they can survive in intense radiation areas.
Knowing more about the effects of the solar wind is not only important to those of us who live on Earth. It will be critical to know how to mitigate its effects once our astronauts travel back to the Moon and beyond for extended periods of time.
If the Sun sneezes, Earth catches a cold, because we always feel the impact of what happens on the Sun thanks to the solar wind.
Get blown away by the science behind the solar wind at
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The Period Of The Solar Minimum
Intense solar activity such as sunspots and solar flares subsides during solar minimum, but that doesn't mean the sun becomes dull. Solar activity simply changes form
High up in the clear blue noontime sky, the sun appears to be much the same day-in, day-out, year after year.
But astronomers have long known that this is not true. The sun does change. Properly-filtered telescopes reveal a fiery disk often speckled with dark sunspots. Sunspots are strongly magnetized, and they crackle with solar flares-magnetic explosions that illuminate Earth with flashes of X-rays and extreme ultraviolet radiation. The sun is a seething mass of activity.
Until it's not. Every 11 years or so, sunspots fade away, bringing a period of relative calm.
This is called solar minimum and it's a regular part of the sunspot cycle.
The sun is heading toward solar minimum now. Sunspot counts were relatively high in 2014, and now they are sliding toward a low point expected in 2019-2020.
While intense activity such as sunspots and solar flares subside during solar minimum, that doesn't mean the sun becomes dull. Solar activity simply changes form.
For instance, during solar minimum we can see the development of long-lived coronal holes.
Coronal holes are vast regions in the sun's atmosphere where the sun's magnetic field opens up and allows streams of solar particles to escape the sun as the fast solar wind.
We see these holes throughout the solar cycle, but during solar minimum, they can last for a long time - six months or more. Streams of solar wind flowing from coronal holes can cause space weather effects near Earth when they hit Earth's magnetic field. These effects can include temporary disturbances of the Earth's magnetosphere, called geomagnetic storms, auroras, and disruptions to communications and navigation systems.
During solar minimum, the effects of Earth's upper atmosphere on satellites in low Earth orbit changes too.
Normally Earth's upper atmosphere is heated and puffed up by ultraviolet radiation from the sun. Satellites in low Earth orbit experience friction as they skim through the outskirts of our atmosphere. This friction creates drag, causing satellites to lose speed over time and eventually fall back to Earth. Drag is a good thing, for space junk; natural and man-made particles floating in orbit around Earth. Drag helps keep low Earth orbit clear of debris.
But during solar minimum, this natural heating mechanism subsides. Earth's upper atmosphere cools and, to some degree, can collapse. Without a normal amount of drag, space junk tends to hang around.
There are unique space weather effects that get stronger during solar minimum. For example, the number of galactic cosmic rays that reach Earth's upper atmosphere increases during solar minimum. Galactic cosmic rays are high energy particles accelerated toward the solar system by distant supernova explosions and other violent events in the galaxy.
During solar minimum, the sun's magnetic field weakens and provides less shielding from these cosmic rays. This can pose an increased threat to astronauts traveling through space.
Solar minimum brings about many changes to our sun, but less solar activity doesn't make the sun and our space environment any less interesting.
For more news about the changes ahead, stay tuned
