Sitting in your office watching and cursing the rainy outdoors, have you ever wondered what the weather beyond our protective atmosphere is like?
Yes, there is weather even in the empty space above Earth’s atmosphere. Space weather typically refers to phenomena resulting from solar activity. It’s also one of the latest content additions to Wolfram|Alpha. Space weather includes things like sunspots, solar X-rays, and solar wind, as well as their effects on the Earth itself (e.g. aurorae, radio communication blackouts, and in extreme cases power outages).
The Sun has an 11-year cycle. Every 11 years, the number of sunspots rises to a peak and then falls to a minimum. Sunspots result from areas of strong magnetic fields on the Sun that cool the surrounding gas and makes the gas appear darker. When these tangled magnetic fields reconnect, the plasma carried along with it can be flung with huge amounts of energy away from the Sun. If it is directed toward Earth, we may observe a number of effects. Depending on how the magnetic field is oriented, it may bounce off the Earth’s magnetic field with no effect. If oriented the other way, the plasma funnels down the Earth’s magnetic field lines until it encounters the atmosphere, causing it to glow. This glowing is known as the aurora borealis in the northern hemisphere and the aurora australis in the southern hemisphere.
The sunspot cycle likely plays a role in Earth’s global climate. The exact nature of its effect is still a hot area of active research. More sunspots mean more energy is likely to be absorbed by the Earth from the Sun. Fewer sunspots mean less energy and potentially a cooler climate. Between 1645 and 1715, sunspots on the Sun nearly vanished. During the same period, called the Maunder minimum, Europe experienced colder-than-average temperatures, contributing to what some have called “the little ice age”. Data for sunspots goes back much further than most other space weather data. Most other phenomena could not be measured until the advent of artificial satellites, and many much more recently than that.
In 1859, the first and most powerful solar flare ever observed occurred, known as the Carrington event. Within a couple of days of the flare, the Earth’s magnetic field oscillated wildly from the magnetized plasma thrown toward us. The magnetic field lines of the Earth bounced back and forth across telegraph wires, causing massive failures and even melted wires from the induced currents. An event of that strength today would cause untold havoc, as we are far more dependent on telecommunications via both satellites and land-based wires.
One example of how space weather can affect us today can be seen with artificial satellites. The Galaxy 15 spacecraft became “rogue” (stopped responding to commands) on April 5, 2010, when its communications package became stuck on during a solar storm. Notice that day’s peaks in interplanetary magnetic field, the solar wind, and the Kp index.
Its orbit has been drifting into the paths of other satellites, risking collisions and the possibility of interfering with other satellite signals nearby. The most recently affected satellite, AMC-11, relays HDTV signals for NBC, MTV, Discovery, and several other well-known stations. This graphic shows how close the satellites are:
They are so close you can’t resolve them. Their orbits and positions are nearly on top of each other. Galaxy 15 continues to drift out of control, and its path will eventually carry it further from AMC-11.
Space weather is an important area of study, both for the preservation of communication, the safety of astronauts, and its effect on our climate. You can explore this area further by visiting the examples page for space weather, or jump over to the Wolfram|Alpha Community astronomy forum to spark up a conversation with other enthusiasts.