The aurora borealis is normally solely seen to the north, however two weeks in the past the night time sky was crammed with twinkling curtains of pink and inexperienced mild that could possibly be seen as far south because the US. Individuals in Texas and Hawaii acquired out of their automobiles to observe and take photos.
The explanation for this mild present was a very sturdy explosion of the photo voltaic wind – electrically charged particles flew away from the solar at an unbelievable velocity. And as we method the height of the present photo voltaic cycle, a interval of heightened photo voltaic storms that happen each 11 years, there’s much more to come back.
That is one instance of what scientists name “area climate,” which pertains to the interplay between the Solar and Earth. Not all results of area climate are lovely, and a few are downright harmful. However the physics behind it’s fairly cool. Let’s test!
Blowin’ within the Wind
You would possibly consider the solar as an enormous ball of fireside, nevertheless it’s not. (Fireplace is a chemical response between oxygen and carbon.) The solar is definitely an enormous nuclear fusion reactor. Within the nucleus, protons are pressured collectively underneath excessive stress. These protons stick collectively to kind the nucleus of a helium atom with two protons and two neutrons. (Two of the protons decay into neutrons).
However wait! A helium nucleus has much less mass than the 4 protons we began with. This mass just isn’t misplaced – it’s transformed into power, in response to Einstein’s well-known equation E = mc2the place E it is power m is mass, and c is the velocity of sunshine. That final quantity is big—mild travels at 300,000 kilometers per second squared—which signifies that even a small lack of mass creates a LOT of power. This is the reason the solar is so sizzling, with a core temperature of 27 million levels Fahrenheit. Sure, it is rather sizzling.
With this intense warmth, the gases within the outer a part of the Solar kind a plasma during which electrons are torn from their atoms, leaving free electrical expenses (largely electrons and protons) spinning round. A few of them transfer quick sufficient to flee the gravitational pull of the solar. These ejected particles are what we name the “photo voltaic wind”.
You possibly can see the impact of the photo voltaic wind because it collides with the comet. Comets are mainly massive soiled snowballs that orbit the solar in lengthy ellipses. When approaching the solar, its icy physique sublimates and turns right into a fuel. A few of this fuel good points sufficient power to ionize (electrons are launched from atoms), leaving an electrically charged fuel. Then, when the photo voltaic wind hits, it pushes this ionized fuel away, making a tail tens of thousands and thousands of miles lengthy.
Enjoyable reality: You would possibly assume that the tail trails behind a comet like a jet path, nevertheless it would not! It extends from the Solar – that’s, largely to the aspect of the comet’s path of movement.
Why now?
However what causes the photo voltaic wind to pressure a lot each 11 years? Effectively, just like the Earth, the Solar has a magnetic subject, however it is rather unstable. Because the Solar just isn’t a stable object, totally different elements of it rotate at totally different speeds. This causes its magnetic subject to twist and warp, and about each 11 years it really flips and reverses polarity. The final time it occurred was in 2013, and right here we’re in 2024.
These transferring magnetic subject strains can break via the floor, creating sunspots and unusual geysers of plasma generally known as photo voltaic flares. Why does this occur? As electrical expenses spin round, they are often pushed and pulled by the magnetic subject. You possibly can see for your self with copper wire and a battery. Should you place a wire close to a stationary magnet after which join the ends in order that present flows, the wire will transfer. Test it out: