
	Where results make sense

Topic: Rotation period

	Rotation Period and Day Length
		As a result, the rotation period of a planet which has a retrograde rotation is a negative number, as shown in the table for the three planets which have such a rotation.
		To explain why the day length, or synodic period of rotation, is different from the sidereal period of rotation, we consider how a given place moves around a planet, and the way in which this changes its view of the sky, during one rotation period.
		Since these objects are rotating slowly, it takes them a long time to rotate through that large angle, and during that time, their orbital motions carry them through a substantial additional angle, making the difference between the rotation period and the day length even greater.
	cseligman.com /text/sky/rotationvsday.htm (2489 words)

	Sun - Open Encyclopedia (Site not responding. Last check: 2007-10-21)
		The Sun is a near-perfect sphere, with an oblateness estimated at about 9 millionths (mostly due to the gravitation of Jupiter), which means the polar diameter differs from the equatorial by 10 km at most.
		This is partly because the centrifugal effect of the Sun's rather sedate rotation is 18 million times weaker than its surface gravity (at the equator).
		The differential rotation of the Sun's latitudes causes its magnetic field lines to become twisted together over time, causing magnetic field loops to erupt from the Sun's surface and trigger the formation of the Sun's dramatic sunspots and solar prominences.
	open-encyclopedia.com /Sun (913 words)

	Rotation Period (Site not responding. Last check: 2007-10-21)
		Rotation period is the time required for a body to rotate about its axis.
		The rotation period for mars is from Physical Solar System Data and the sideral rotation period for the moon is from Solar System Data.
		Rotation period is used with latitude and radius to calculate rotation boost.
	members.axion.net /~enrique/rotationperiod.html (118 words)

	Phase explanation (Site not responding. Last check: 2007-10-21)
		If one attempts to find a rotation period of an asteroid at a large phase angle, the result may be correct if the asteroid is spherical and has a uniform albedo (reflectivity) over its entire surface.
		The possible result is that the apparent rotation period and amplitude (involving a combination of these effects) may vary over this period of time.
		The ideal situation would be to measure a rotation period over a short period of time (say 2 or 3 consecutive nights from dusk to dawn) while the asteroid is within, say, 10 degrees of opposition.
	www.astro.queensu.ca /~irwin/phy215/y2002/phase_explain.html (411 words)

	[No title] (Site not responding. Last check: 2007-10-21)
		The internal period, what you might think of as the "true" rotation period, is tied to Neptune's magnetic field (which is tied to the core of the planet), and was measured by the Voyager 2 spacecraft as it flew by Neptune in 1989.
		That is what we call "the" rotation period, since it presumably does not change, or at least changes only very very slowly.
		However, in addition to this internal period of 16 hours 07 minutes, the winds on Neptune are confined to bands on the planet, much like the winds of Jupiter blow in bands (these bands are the patterns of streaks you see when you look at a picture of Jupiter or Saturn or Neptune).
	quest.arc.nasa.gov /hst/QA/Neptune-Pluto_Orbits/Period_of_Neptune.1 (478 words)

	ROTATION PERIOD AND RECUPERATION TIME IN PEACEKEEPING OPERATIONS
		Another point which is important for research into the effectiveness of the period of rest is the delay with which mental or physical problems may become manifest, sometimes lasting dozens of years.
		An endeavor is made to adhere to a minimum period of rest of two years after a deployment.
		If servicemen are unable to be accompanied by their families, the minimum period of rest after deployment is one year.
	www.ijoa.org /imta96/paper01.html (2741 words)

	rotation period of Venus
		The 23 hours period is confirmed by Francesco de Vico (1805-1848) which obtains the incredibly precise value of 23h 21mn 21.934s, after an observation campaign carried out between 1839 and 1841, during which he could follow planet in full day.
		In fact, the true period of rotation of Venus will be discovered only in 1962, thanks to the radar observations carried out by the Jet Propulsion Laboratory (the USA) which make it possible to be freed from the cloud cover.
		This period of rotation, associated to a 224,7 days orbital period leads to a duration of the Venusian "day" of 116 terrestrial days, with a Sun which rises to the west and sets in the east.
	www.imcce.fr /Equipes/ASD/Venus/venus1_en.html (498 words)

	[No title] (Site not responding. Last check: 2007-10-21)
		An apparent sidereal day is the time it takes for the Earth to turn 360 degrees in its rotation; more precisely, is the time it takes the vernal equinox to make two successive upper meridian transit.
		The reason there is one more sidereal day than "normal" days in a year is that the Earth's orbit around the Sun cancels one sidereal day out, giving observers on Earth 365 (and a quarter) days, even though the planet itself rotated 366 (and a quarter) times.
		A mean sidereal day is reckoned, not from the actual transit, but from the transit of the mean vernal equinox (see: mean sun).
	www.informationgenius.com /encyclopedia/s/si/sidereal_day.html (155 words)

	The Scripps Research Institute - Select a Lab
		Laboratory rotations are designed to ensure that students select a thesis advisor and laboratory that matches their area of scientific interests.
		The rotation proposal is a brief outline of the proposed research, and is signed by both the student and the rotation advisor.
		For students who elect to perform a single rotation and to remain in that same laboratory for thesis research, the rotation period will typically begin in the summer and end when that student formally joins a laboratory at the end of November.
	www.scripps.edu /phd/biograd/selectlabbio.html (355 words)

	ASTRO-1 Lecture 12
		period is the period of rotation of a planet around itself.
		rotates once every 2/3 of a Mercury year (58 day rotation period, 88 day orbital period); the rotation is prograde (i.e., in the same sense as the orbital motion).
		The rotation period is 24.6 hours and the rotation axis is tilted by 25.2 degrees relative to the axis of the orbit (very similar to Earth).
	www.astro.psu.edu /users/mce/A1/lect12.html (560 words)

	ESA - Science - Home - How do we measure a day on Saturn?
		This ‘rotational modulation’ technique is particularly useful for measuring the ‘days’ of the giant gas planets, such as Jupiter and Saturn, which have no surfaces and are covered by clouds that make direct visual measurements impossible.
		The puzzle is that this is about six minutes, or one percent, longer than the rotational period measured by the Voyager 1 and Voyager 2 spacecraft during their fly-bys of the 1980s.
		They did not think that there could be any process which would cause the rotation of the entire planet to actually slow down, so there has to be some kind of ‘slippage’ between the deep interior of the planet and the magnetic field, which controls the charged particles responsible for the radio emission.
	www.esa.int /esaSC/SEMIWQL26WD_index_0.html (577 words)

	North Coast, (TSA) Public Discussion Paper (Site not responding. Last check: 2007-10-21)
		This is about double the rotation periods of 80 -150 years used by the Ministry of Forests for most of the North Coast area.
		Using the Nisga’a rotation period in the model will result in an allowable annual cut that is approximately one-half or less of an allowable annual cut based on the rotations used by the Ministry of Forests.
		A longer rotation period is necessary because of the often poor growing conditions and harsh climate in the North Coast area, which means that trees require longer periods to grow to merchantable size.
	www.for.gov.bc.ca /hts/tsr1/pdp/tsa/21/21nc-034.htm (144 words)

	SparkNotes: Mercury: Mercury's Rotation
		The reason for the slow rotation of Mercury is the action of 'tidal forces' between the planet and the Sun.
		It is quite possible that the period of rotation of Mercury was much shorter long ago, at the time of the planet's formation.
		As the rotation of the planet proceeds, the distance between that point of the surface and the center of the planet periodically changes.
	www.sparknotes.com /astronomy/mercury/section3.rhtml (510 words)

	Rotation of sun and planets
		Also, from the rotation Equation we can calculate the rotation period of Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto because all these planets are circled by another moons with small mass (m).
		The rotation period of a large body is highly effected by the inclination degree of the small body orbit.
		Over the 12-year period from 1969 to 1981, scientists kept track of the distance to the Moon and found it to be increasing approximately 4 cm per year.
	www.geocities.com /saeles/planetsrotation.htm (853 words)

	Scientists Find That Saturn's Rotation Period Is A Puzzle
		Scientists studying the rotational modulation of radio emissions from Saturn with the Cassini spacecraft are puzzled by apparent long-term variations in the radio rotational period of Saturn.
		The currently accepted rotation period of Saturn came from radio measurements obtained during the Voyagers 1 and 2 flybys of Saturn in 1980-81, and is 10 hour 39 minutes and 24 seconds plus or minus 7 seconds.
		He says that in order to determine the rotation period he analyzed the recurring pattern of radio bursts from the planet for a little over a year from April 29, 2003, to June 10, 2004.
	www.uiowa.edu /%7Eournews/2004/june/062804saturn-rotation.html (850 words)

	Period of Rotation of the Sun
		The sun rotates from west to east in the same direction as the earth.
		At the equator the sun's rotational period is twenty-five days while at higher latitudes the sun tends to rotate more slowly.
		The rotational period near the poles it is thirty-five days.
	hypertextbook.com /facts/1999/RadhikaKapoor.shtml (281 words)

	Carrington Rotation Start and Stop Times (Site not responding. Last check: 2007-10-21)
		The synodic rotation rate varies a little during the year because of the eccentricity of the Earth's orbit; the mean synodic value is about 27.2753 days.
		The rotation of the Sun and the orbital motion of the Earth are in the same direction (both counterclockwise when viewed from north of Earth's orbital plane).
		As a consequence the apparent (synodic) solar rotation period is a bit longer than the true (sidereal) period.
	umtof.umd.edu /pm/crn/CARRTIME.HTML (649 words)

	A closer look at the synodic effect (Site not responding. Last check: 2007-10-21)
		Flashing satellites are always under the influence of the synodic effect, the effect that is responsible for the difference between the rotation period and the flash period.
		The flash period is the time between two flashes as seen by the observer, the rotation period is the time the rocket needs to turn around its axis once.
		If the satellite were stationary with respect to the observer, the flash period would be equal to the rotation period.
	www.satobs.org /flash/92/node7.html (1351 words)

	Properties of the Sun
		Images of the Sun are used to find the rotation period of the Sun, and to find the velocity of matter leaving the Sun through a coronal mass ejection.
		The rotation period of an object is the time it takes to spin on its axis once.
		Since the spots are always moving at the same velocity, the period of the rotation of the Sun can be found using a ratio.
	www.astro.washington.edu /labs/clearinghouse/labs/Propsun/lab.html (876 words)

	Sunspot Project Home
		It was also predicted that the rotation period of the sun determined by sunspots would be about 27 days.
		The longer periods of time were closer to the actual time because the margin of error with the ruler was smaller.
		To discover the rotation period of the sun, if there is a daily change in the number of spots, and the duration of sunspots, a sunspot map was printed and a spreadsheet was setup.
	www.qacps.k12.md.us /cms/sci/PROJJNN.HTM (1780 words)

	Cassini-Huygens: News-Press Releases-2004
		Here's the puzzle: That is about 6 minutes, or one percent, longer than the radio rotational period measured by the Voyager 1 and Voyager 2 spacecraft, which flew by Saturn in 1980 and 1981.
		"We all agree that the radio rotation period of Saturn is longer today than it was in during the Voyager flyby in 1980," he said.
		Gurnett said, "Although Saturn's radio rotation period has clearly shifted substantially since the Voyager measurements, I don't think any of us could conceive of any process that would cause the rotation of the entire planet to actually slow down.
	saturn.jpl.nasa.gov /news/press-releases-04/20040628-pr-a.cfm (768 words)

	Rotation and Flash Period (Site not responding. Last check: 2007-10-21)
		Cylinders that have a rotational state that is between spinning and tumbling do not necessarily give off two flashes per period, nor are the flashes necessarily symmetrical.
		Objects with long rotation periods are also more prone to a larger synodic effect, for essentially the same reason (more change of geometry per period since the period is long).
		You can circumvent this problem by counting an even number of periods, since even for non-tumbling rockets the time between the first and the third flash is the rotation period (influenced by the synodic effect, of course).
	www.satobs.org /tumble/rotandfp.html (1058 words)

	No Title (Site not responding. Last check: 2007-10-21)
		Rotation Period of the Nucleus of the Comet Halley
		The plots are showing intensity variations which can be interpreted as the effect of the rotation of the nucleus.
		On the basis of this results I can conclude that the real rotation period of the comet Halley is about 7 days.
	www.lpi.usra.edu /meetings/dps97/html/H2918/H2918.html (132 words)

	Self-study Guide (Site not responding. Last check: 2007-10-21)
		The period of rotation of a Solar System object is the length of time it takes that object to spin once around on its axis.
		First, let's consider how to find the period of rotation of an object, be it a planet, orange, or basketball.
		You are ready now to figure out rotation rates (or angular velocities), and periods of rotation of some planets.
	cse.ssl.berkeley.edu /lessons/indiv/spin/selfstudy.html (684 words)

	Determining the Rotation Period
		Compare your value for the period with the established value of 27.27 days, first as a difference in days and then as a percent error.
		The period you have found is the synodic period, the apparent rotation period of the Sun as seen from the Earth.
		The rotation period of the Sun as seen from a fixed point in space such as a star is called the sidereal period.
	www.astro.virginia.edu /~teacha/130_manual/node95.html (838 words)

Try your search on: Qwika (all wikis)