In this visual age, a good share of the scientific mission is explaining, clearly and memorably, what scientists are learning through images. Above, we see how Earth's strong magnetic field protects us from damaging radiation – protection that our planetary neighbors lack.

Seeing => Theorizing

Careful observation, without expectation or desired conclusion, is the bedrock of science. Seeing what is really happening, and questioning why leads naturally to wondering about why: hypothesis, “a proposed, testable explanation for a phenomenon or a relationship between variables that serves as a starting point for further investigation.”

Good, conscientious science (do you see the word science in the word conscientious?) carries on from forming an hypothesis to further testing, observation, and analysis – does the seeing conform to the hypothesis? Might there be a simpler explanation?

Everything should be as simple as possible . . . . . . but no simpler. – Albert Einstein

Rendering

All the way from observation to conclusion, one of science's most powerful tools is imaging – sketches, diagrams, graphs, photos, computer-aided renderings – of what is seen. Often, as our tools have become more powerful, the resulting images are strikingly beautiful as well as powerfully instructive – as an example, the image (at the top of this page) of solar wind deflected from Earth by our planet's powerful magnetic field.

Here's an explanation of the aurora borealis, the photogenic phenomenon of solar wind striking Earth's Upper atmosphere.

Temperature v. Heat

When we say ‘it’s hot!’ we describe our experience of air molecules bouncing off our skin. That’s temperature: the average speed of the molecules in a material. In the US we use Fahrenheit degrees, an older scale where water freezes at 32° and boils at 212° (at sea level), and normal human body temperature is 98.6°. Scientists, thinking those numbers inconvenient, defined the Celsius scale, where water freezes at zero (0°C) and boils at 100°C.

In the vacuum of space, there are no molecules, but there is plenty of heat: the visible surface of the sun, the photosphere, is 5,000°K -- degrees Kelvin.

In 1848, William Thomson, who was later ennobled as Lord Kelvin, proposed the revolutionary theory that at a certain point, molecules completely stop moving, and that point was another logical reference point for measuring heat. Somewhat later, scientists confirmed his theory: all physical molecular motion stops at -273°C.

The Kelvin (°K) heat scale starts there, at the lowest measurable temperature, 0°K. The Kelvin scale is also used to measure the temperatures of very hot objects, like the surface of the Sun.