radius indicating system
11Observable universe — For a general discussion of the universe, see Universe. Visualization of the 93 billion light year – or 28 billion parsec – three dimensional observable universe. The scale is such that the fine grains of light represent collections of large… …
12Uranus — /yoor euh neuhs, yoo ray /, n. 1. Astron. the planet seventh in order from the sun, having an equatorial diameter of 32,600 miles (56,460 km), a mean distance from the sun of 1,784 million miles (2,871 million km), a period of revolution of 84.07 …
13Distress radiobeacon — PLB redirects here. For other uses, see PLB (disambiguation). Emergency position indicating radio beacons or EPIRBs Distress radio beacons, also known as emergency beacons, ELT or EPIRB, are tracking transmitters which aid in the detection and… …
14Geology of Mars — Mars   Mars as seen by the Hubble Space Telescope Designations …
15Ganymede (moon) — Ganymede Image of Ganymede s anti Jovian hemisphere taken by the Galileo probe. Lighter surfaces, such as in recent impacts, grooved terrain and the whitish north polar cap at upper right, are enriched in water ice. Discovery …
16eye, human — ▪ anatomy Introduction specialized sense organ capable of receiving visual images, which are then carried to the brain. Anatomy of the visual apparatus Structures auxiliary to the eye The orbit The eye is protected from mechanical injury… …
17Mars — This article is about the planet. For other uses, see Mars (disambiguation) …
18nebula — nebular, adj. /neb yeuh leuh/, n., pl. nebulae / lee , luy /, nebulas. 1. Astron. a. Also called diffuse nebula. a cloud of interstellar gas and dust. Cf. dark nebula, emission nebula, reflection nebula …
19Geology of Venus — Radar image of the surface of Venus, centered at 180 degrees east longitude Venus is a planet with striking surface characteristics. Most of what is known about its surface stems from radar observations, mainly images sent by the Magellan probe… …
20Glossary of rail terminology — Rail transport Operations Track Maintenance High speed Gauge Stations …
