In the night sky: Orion
In the night sky: Orion

Start this free course now. Just create an account and sign in. Enrol and complete the course for a free statement of participation or digital badge if available.

Orion Glossary


Browse the glossary using this index

Special | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | ALL

Page: (Previous)   1  2  3  4  5  6  7  8  9  10  ...  12  (Next)
  ALL

E

electron degeneracy pressure

An effect of quantum physics that provides the support against gravity in a white dwarf star.


elliptical galaxy

A galaxy that appears as an elliptical distribution of stars (typically old stars).


emission line

A spectral line produced when atoms of a particular type emit photons with a specific energy.


emission spectrum

A spectrum containing emission lines. A pattern of narrow bright lines at specific wavelengths, generally superimposed on a dark background. The wavelengths of the lines are characteristic of the composition of the excited gas that produces them.


event horizon

The boundary around a black hole within which the escape velocity exceeds that of light. Note that this does not consist of a solid, physical surface.


exoplanet

A planet orbiting a star other than the Sun. Shortened version of extrasolar planet.


exponent

The power to which a number or quantity is raised. For example, 103 is read as 'ten to the power 3' and means 10 x 10 x 10, where the exponent (or index) is '3'.


extragalactic

Of or pertaining to the Universe outside our own galaxy.


extrasolar planet

A planet orbiting a star other than the Sun. Also abbreviated to exoplanet.


F

flare

A highly energetic form of solar activity, typically lasting a few hours, caused by the sudden release of magnetic energy in the corona.



Page: (Previous)   1  2  3  4  5  6  7  8  9  10  ...  12  (Next)
  ALL


Take your learning further

Making the decision to study can be a big step, which is why you'll want a trusted University. The Open University has 50 years’ experience delivering flexible learning and 170,000 students are studying with us right now. Take a look at all Open University courses.

If you are new to University-level study, we offer two introductory routes to our qualifications. You could either choose to start with an Access module, or a module which allows you to count your previous learning towards an Open University qualification. Read our guide on Where to take your learning next for more information.

Not ready for formal University study? Then browse over 1000 free courses on OpenLearn and sign up to our newsletter to hear about new free courses as they are released.

Every year, thousands of students decide to study with The Open University. With over 120 qualifications, we’ve got the right course for you.

Request an Open University prospectus371