This is an artist's rendering of solar wind coming towards the Earth and its magnetosphere.
Click on image for full size
The Sun produces a constant stream of particles which billow out into space. In fact, 1 million tons of particles come from the Sun every second! This stream of particles is called the solar wind.
The solar wind plasma is very thin. Near the Earth, the plasma is only about 6 particles per cubic centimeter, compared to 2.5 10^19 molecules/cm3 in the Earth's sea-level atmosphere.Nevertheless, it is responsible for such unusual phenomena as:
The solar wind consists mostly of protons and electrons, but it also consists of ions of almost every element in the periodic table. It is considered to be the continual expansion of the Sun's atmosphere.It is a remmnant of the T-Tauri phase of stellar evolution when the newly ignited Sun blew massive quantites of its residual mass into space.
The solar wind emanates from the Sun in all directions, but seems to emmanate most readily from the Sun's coronal holes. Exactly what causes the solar wind to be accelerated, or "blown" into space is not well understood. Such phenomenon are being investigated by the SWICS and SWOOPS instruments of the Ulysses mission.
The particles of the solar wind, and the Sun's magnetic field (IMF) are stuck together, therefore the solar wind carries the IMF (interplanetary magnetic field) with it into space. Once blown into space, the particles travel at supersonic speeds of 200-800 km/sec and do not slow down until they reach the termination shock within the heliosphere, where the solar wind slows from supersonic to subsonic speeds. The Heliosphere is the entire region of space influenced by the Sun.
Shop Windows to the Universe Science Store!
Our online store
includes issues of NESTA's quarterly journal, The Earth Scientist
, full of classroom activities on different topics in Earth and space science, ranging from seismology
, rocks and minerals
, and Earth system science
You might also be interested in:
Plasma is known as the fourth state of matter (the first three states being solid, liquid and gas).Matter in ordinary conditions on Earth has electrons that orbit around the atomic nucleus. The electrons...more
As the ices of the comet nucleus evaporate, they expand rapidly into a large cloud around the central part of the comet. This cloud, called the coma, is the atmosphere of the comet and can extend for millions...more
Motions within Earth's metallic core generate the planet's global magnetic field. This magnetic field extends beyond Earth's surface and atmosphere into the space surrounding our home planet. The interaction...more
AU stands for Astronomical Units. Distances in space are too large to measure in Earth standards like miles or kilometers. For distances too large to measue in AU, we use light years. A light year is the...more
The solar wind is formed as the Sun's topmost layer blows off into space carrying with it magnetic fields still attached to the Sun. Gusts and disturbances form in the solar wind associated with violent...more
For a planet to be affected by a blob of material being ejected by the sun, the planet must be in the path of the blob, as shown in this picture. The Earth and its magnetosphere are shown in the bottom...more
The aurora we are most familiar with is the polar aurora. This is what people are referring to when they speak of the northern or southern lights. But there are other less-known auroral activity, such...more