Posts Tagged ‘orbit around the sun’
What is the radial acceleration of the earth toward the sun?
The radius of the earth’s orbit around the sun (assumed to be circular) is 1.50 x 10^8 km, and the earth travels around this orbit in 365 days.
Tags: 365 days, orbit around the sun, radius of the earth
How do you measure velocity in the void of space?
Speed is measured relative to a stationary object. Velocity is determined by calculating the time it takes to travel a known distance from a stationary object. A cars speedometer measures speed relative to the stationary ground it is traveling on. An airplane measures speed by the same thing, by how long it takes to travel between points of a known distance on the ground.
So when it is said that a spacecraft is hurtling at 46,000 miles per hour beyond the orbit of Pluto towards the next star, what is that speed being compared against? In that part of space, there is no stationary object to calculate velocity. Is it still being compared to a stationary object on the surface of the Earth? At that distance, the Earth is traveling through space in orbit around the sun, which is traveling in orbit around the galaxy, which is traveling through space around who knows what.
So, what is the spacecraft traveling at 46,000 miles per hour from or towards that can be measured?
Tags: airplane, cars, earth, galaxy, measures, miles per hour, orbit around the sun, pluto, spacecraft, speedometer, stationary object, velocity
Pluto Is Out — A Homeschool Science Lesson in Astronomy
Pluto is out, and Zena and Ceres are in. Well, almost. Now all three are out.
Recently, Michael Brown, an astronomer from Caltech, discovered what he thought was a new planet, which he called Zena. He presented his findings and submitted his studies to the 26th General Assembly of the International Astronomical Union (IAU) who met last week, 20 26 August 2006 in Prague, Czechoslovakia to discuss this new discovery and to review the selection criteria for naming planets. Of the 2,700 delegates who attended the meeting only 720 were still in attendance at the end of the week. Only about 400 delegates were on hand the final day but only a handful of members were eligible to vote on a revised description of what constitutes a planet and Brown’s studies were accepted. They added Zena to the roster of the Suns planets (also knows as UB313, Zena is larger than Pluto). They also accepted a second nomination, Ceres.
Then suddenly, in a direct reversal of their previous decisions the IAU decided that the long-standing member planet, Pluto, no longer met the criteria to be a planet. Pluto was demoted to space dust. The two other small solar system bodies nominated, Zena and Ceres, were then summarily rejected.
The IAU also redefined the three criteria necessary to qualify an object as a planet.
1. A planet must be round in shape. What this means is that is planet must be large enough to have had its mass pulled into a round shape as the result of its own gravitational forces. It was also suggested, but not made part of the definition, that a planet must be at least 1000 kilometers in diameter.
2. Planets must have a defined, regular orbit around the Sun, and not be either stars themselves or satellites of other planets.
3. To be a planet a space object must dominate its own orbit and clear its own area of other smaller space objects.
A “dwarf planet” was defined as a celestial body that is in an orbit around the Sun, has sufficient mass for its own gravitational forces to assume a hydrostatic equilibrium or “nearly round” shape, has not cleared its orbital neighborhood of other space objects, and it is not a satellite.
The IAU also resolved that all other space objects, except satellites orbiting the Sun, shall be referred to collectively as “Small Solar-System Bodies”
The old mnemonic My very energetic mother just served us nine pizzas, by which millions of people learned to recite the planets, no longer applies. However, We do have a new one to help you remember the planets in the new line up.
My very Energetic Mother Just Served Us Noodles.
Here are some other, more original suggestions:
My very exhausted mother just sent us nachos
Make Very Extraordinary Meals of Jell-O, Strawberries, and Unsalted Nuts.
Just in case you may have forgotten, the names of the planets they are, listed in order of their distance from the Sun, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and the newly demoted “dwarf planet”, Pluto.
Try making up your own mnemonic and get the kids involved, too. This could very easily be made a part of one of your science lessons. But dont use Pluto, Zena, or Ceres in your new mnemonic. At least not for now, the IAU may change their minds at their next meeting in 2009.
Homeschool Science: Pluto, Zena, Ceres Astronomy
Author: John Finnigan
Article Source: EzineArticles.com
Provided by: Digital TV, HDTV, Satellite TV
Fun Astronomy Facts
If you want to measure our solar system, how would you do it? This simplest way is to measure it in light years. For those not familiar with the term, a light-year is the distance that light travels in a vacuum in one year. This is because the distances between stars is so huge that it is otherwise very challenging to imagine them. A light year is exactly 9,460,730,472,580.8 kilometers. Putting this into real world distances, the Milky Way is approximately 100,000 light-years across.
The Earth is one of nine planets that form the Solar System, so called because the sun, the source of solar energy, is the central point around which all the planets revolve. So far, scientists have not been able to establish or prove the existence of life forms on any other planet within the solar system. Often, the search for other life forms has focused on looking at the climatic conditions of the celestial body in question. Scientists assume that life forms on a different planet would need similar conditions as life on earth, such as oxygen, light and water, to grow. This may or may not be true.
Other than the sun, no other celestial body significantly affects the earth as the moon does. It is well know that the moon affects the rise and fall of the ocean tide. Such is the effect of the gravitational pull between the earth and the moon. Jupiter is easily the largest planet in our solar system. To put its size in context, Jupiter is more than 300 times the mass of Earth. Here is the interesting part; Jupiter has 63 moons that orbit it and yet it is not the planet in the Solar System with the most moons. That honor belongs to the ringed-planet Saturn, which has 66 moons identified so far. Pluto, the farthest flung among the nine planets, has been the subject of heated debate on whether it really qualifies to be considered a planet. Nowadays, it is classified as a dwarf planet. Its orbit around the Sun is somewhat heavily elliptical. In fact, there are instances where Pluto is actually closer to the Sun than Neptune, the planet that precedes it.
Now speaking of size within the Solar System, well, let us just say that the Sun is unmatched. Did you know that the Sun comprises more than 99% of the total mass of the entire solar system? Jupiter actually takes up much of the remaining proportion. Surface temperatures on the Sun stand at 5000 Kelvins (4727 degrees Celsius). With temperatures at its core reaching a 15.6 million Kelvins (15.6 million Celsius), the Sun is truly a celestial spectacle. It gets even better when one realizes that the Sun is classified as a class G star. Stars are classified in six major categories that tie in to the surface temperature and brightness. The categories are M, K, G, F, A, B and O listed in ascending order brightness and surface temperature. You can see that the Sun falls on the lower end of this classification. Category B and O are rare in the universe while most stars are in the category M and emit less heat and light energy. That said, the Sun is within the 90th percentile by mass among all stars. We have found other stars that are larger than our sun: one is estimated to be approximately 60,000 times bigger.
The Solar System forms a tiny part of the Milky Way Galaxy, a vast conglomeration of stars and planets. What makes astronomy so thrilling is that despite its size, the Milky Way is not the only galaxy in the universe. There are hundreds of billions of galaxies out there, probably more. The closest galaxy to our own Milky Way is Andromeda. Now, brace yourself for the distance: it is 2.3 million light years away. One of the most exciting phenomena for astronomers is the black hole. It is an area of the universe where the concentration of mass is so massive (no pun intended) that the gravitational pull it generates sucks in everything around it. Everything includes light. Remember that the escape velocity for any object in the universe is the speed required to escape the objects gravitational pull. The escape velocity for the Earth is slightly over 11 kilometers per hour while for the Moon is 2.5 kilometers per second. Well for a black hole, the escape velocity exceeds the speed of light. That is how strong the pull is.
Author: Rachael Stone
Article Source: EzineArticles.com
Provided by: Digital Camera News
Conversation-Stopper – Why Don’t the Space Shuttle and Space Station Fall to Earth?
What happened to gravity? Doesn’t it operate in space?
The answer to the above questions is the same as for, “Why doesn’t the moon fall onto Earth”, or “.. the Earth into the Sun”. Gravity – the attractive force between two masses (or bodies – the product of their masses divided by the square of the distance between the two centers) – does act continually and everywhere; the answer, therefore, is that the Shuttle, Space Station and Moon are each traveling at high speeds and (corresponding) heights, circling Earth, as does the Earth in its orbit around the Sun – and that all are always “falling around” the curvature, e.g. of the Earth. Although the flight path of the orbiting vehicle (or moon, or planet) attempts to be a “straight” line – it is continually being pulled down by gravity – so that as “satellites” they continually travel in stable orbits, circular or elliptical. The same is true throughout the universe, and while attractive forces exist between all bodies in the Universe, each to each other, the factor of distance-squared in the denominator effectively eliminates the significance of all other bodies in comparison to the two involved in satellite orbiting.
To put a numerical perspective upon what has become a casual acceptance of space activities, to achieve a stable orbit, the Shuttle Orbiter vehicle – which does not have propulsive power while orbiting – must rise to a sufficient height above the Earth’s air layer, where the vacuum of space produces no “drag” resistance (generally about 125 miles altitude) – to achieve this, the lift-off propulsion system must propel the orbiting vehicle to approximately 18,000 miles per hour (note: traveling in the easterly direction gains the Earth-surface rotational speed of about 1000 mph).
At the completion of the mission, to return to Earth, the Orbiter is slowed slightly – dropping closer to Earth – smashing into individual air molecules, which are “vaporized” by the impact – a tiny pulse of both “drag” (causing further slowing and lowering of the Shuttle) and also of “heat”. As the Shuttle is slowed and lowered for the reentry mode, the heat build-up develops tremendous temperatures of up to 3000 degrees Fahrenheit – requiring the insulating “tiles”, which cover the lower wing and body surfaces.
The concept of the Space Shuttle is remarkably and functionally (and beautifully) simple and reliable – as a result of reliance upon this function of insulation – in an absolutely hostile, unforgiving space environment of cryogenic iciness plus vacuum. The rentry insulation tiles, invented and developed by NASA and Lockheed Aircraft, shield the Orbiter Spacecraft (fabricated of conventional light, aluminum-alloy thin skin-stringer construction, similar to most sub-sonic aircraft of that era) from re-entry heat – temperatures which would melt the strongest alloy steel.
- The tiles are individually designed for the anticipated reentry temperatures, 6×6 inches in size and average about 1 inch in depth;
- Inside, they are comprised of extremely long, fine filaments of quartz, compressed into the vacuumized tile volume, with a covering of thin glass. The fabrication process – double vacuum, pressurized, is extremely complex. Tile surfaces are relatively easily damaged, the inside appearance likened to white styrofoam – however, when the outside temperature is 3000 degrees F, the backside (attached to the aluminum structure of the Orbiter by ordinary RTV Room Temperature Vulcanizer) – is only 80 degrees F.
- The highest reentry temperatures are on the bottom of wing and body, and at the trailing edges of the control surfaces; there are 30,000 black tiles; NASA has reported the cost at $2500 each.
However, because of the tremendous insulating capability of the tiles, a greatly simplified and reliable Space Shuttle concept has been achievable:
- The Orbiter vehicle itself was essentially designed and constructed much as a conventional aircraft – its only flight function, landing after reentry, uses conventional flight controls, tires and brakes (the landing speed is similar to a commercial jet aircraft, about 160 mph).
- There is no propulsive capability for orbiting or landing, the speed and momentum of the vehicle after reentry, permitting the astronaut-pilot to maneuver the craft into the pre-selected NASA airport and runway for landing.
- The most powerful and efficient rocketry arrangement is therefore designed for the lift-off sequence: two solid rockets (approximately twelve feet in diameter), plus the three Orbiter engines (fueled by the large center fuel-oxidizer tank); all five are fired simultaneously for maximum thrust at lift-off (approximately seven million pounds thrust required) – along with the giant ground-retention explosive bolts at the base of the solid rockets (only attachment of the entire assemblage to the launch platform).
- After twelve minutes of flight, the exhausted solid rockets are depleted and dropped (parachuted and recovered in the ocean); the three on-board engines continue until the center tank is empty, when it is separated; afterwards, the Orbiter, traveling at orbiting altitude and speed, has no more propulsive capability.
A human-interest worry about mankind’s 21st century “Space adventures” is space debris – the remains of space-hardware rocketry that have not, as yet, returned to Earth. Varying in size from complete rocket stages to tiny particles, they are true hazards because of their thousands of mph travel speeds. The larger ones are monitored – just recently, March 5, 2009, warnings about a possible strike of the International Space Station forced the US astronauts to take shelter in the parked Russian Soyuz capsule. Two months ago, two satellites collided in orbit, adding several hundred new pieces of “junk” to the space debris litter-belt circling Earth. The NASA Orbital Debris Program Office is at Johnson Space Center, reporting that about 13,000 such threats are constantly tracked, of about 600,000 total debris items.
Author: Aaron Kolom
Article Source: EzineArticles.com
Provided by: Digital Camera Information
Planet-x-Nibiru Earth Stars and Space
Planet-x-Nibiru
NEW PLANET,SPACE SEARCH.
When Pluto was discovered back in 1930, Planet Astronomers were also observing a massive terrestial mass in Space that caused fluctuations in the Planet orbits of Uranus and Neptune. So intrigued were they that this sparked a massive focus for the search for a new Lunar Planet, Planet X as it was so called,and it’s set to visit us soon.
N.A.S.A.’s CLAIM.
Where time in space is irrelevant, but back on Earth 1993 was a good year for N.A.S.A. They announced an Earth like Planet mass was traveling in an uneven orbit around the Sun. It’s trajectory was indeed discovered to be towards Planet Earth.
More recently adding credence to N.A.S.A.’s claim, was an article published on Feb.28, 2008 in Japan by a scientist named Kyoko Hasegawa from the Kobe University he said that their calculations, using computer simulations led them to believe that this Planet was up to two thirds the size of Earth and was in orbit at the far reaches of our Solar System.
It was only a matter of time before the mysterious Planet X came into view.
PLANET-X-NIBIRU.
So where does Nibiru fit in?
By talking up and manipulating the fore mentioned information, skeptics and believers alike both clung to the belief that this astronomical discovery was, and then declared proof that, Planet X and Nibiru were one of the same.
Planet X Nibiru measures approx. 30 to 70% of the Earths mass and is made up of Ice, Icy Ammonia and Methane. With that you can imagine the surface would be veeerrry cold. The Planet is in an oblong elliptical orbit and circles the Sun every 1,000 years or so. It’s radius is estimated to be 15 to 26 billion killometres. To put it into perspective, if you looked into Space, and managed to see Pluto the celestial size is estimated to be much larger than that and will leave a larger trail than Halleys Commet.
LOOK INTO SPACE.
Observers estimate that by the year 2012 this Planet like mass, will pass through our solar system and we on good old Planet Earth will get the front row seats.
Author: Evert Harder
Article Source: EzineArticles.com
Provided by: Digital Camera Information