Showing posts with label astronomy. Show all posts
Showing posts with label astronomy. Show all posts

Saturday, February 28, 2015

Does the Sun Really Rises and Sets?

Does the Sun Really Rises and Sets?

We often hear from broadcasters, newscasters and weather forecaster the statement “the sun will rise at 5:45 this morning and sunset will be at 6: 03 this afternoon”. The question is “does the sun really rises and sets?”



When the Sun is viewed from the Earth, it looks like that it rises in the east and sets in the west. It appears to us that the Sun is rotating around us when in fact, it is not. Astronomically speaking, it is the Earth that rotates around the Sun. so, it is not correct to say that there is Sunrise or Sunset because the Sun does not come from underground to rise above. It does not also go to an underground to set and rise again.




Technically, there is no sunrise and sunset but people are already used to these terms.  Sunrise and sunset are the common terms being used for the daily appearance and disappearance of the Sun. Some suggested that the terms "sunsight" and "sunclipse" should be used instead of sunrise and sunset.

Thursday, November 3, 2011

Interesting Scientific Facts About the Planet Saturn

One of the largest planets in our Solar System is Saturn. Here’s a list of amazingly important and interesting facts about this planet.

1.) This planet is named after Saturn, the Roman god of agriculture, the equivalent of the Greek’s Cronus.

2.) Saturn is the 2nd largest planet in the Solar System after Jupiter.

3.) It is the 6th planet in order of distance from the Sun.

4.) The planet’s most distinctive feature is a giant system of rings that surrounds the planet at its equator, stretching over twice the width of the planet itself.

5.) 1n 1610, the first person to see the rings was the Italian scientist Galileo with the used of his telescope.




6.)  Saturn when viewed from Earth appears as a yellowish object and is one of the brightest in the night sky.

7.) Saturn takes about 29.5 years to orbit the Sun at an average distance of 1,435 billion km.

8.) Saturn rotates on its axis in about 10.5 hours and is tilted at about 27°, giving the planet distinct seasons.

9.) The diameter of Saturn is about 121,000 km (75,000 mi), and its mass is equal to the mass of about 95 Earths, making it the second largest planet in our solar system after Jupiter.

10.) Saturn is 10 percent wider at its equator than at its poles and has a more oblate (flattened sphere) shape than any other planet.

11.) The National Aeronautics and Space Administration (NASA) launched the orbiter Cassini spacecraft toward Saturn in October 1997 and reached Saturn in July 2004.

12.) Cassini had detected carbon molecules and geysers on Saturn’s moon Enceladus

13.) Saturn is the least dense of the solar system’s planets. The mean density of Saturn is eight times less than that of Earth because the planet consists mainly of the lightweight gas hydrogen.

14.) Saturn to radiate into space three times as much heat as it receives from the Sun.

15.) Saturn receives about 1.1 percent as much sunlight as Earth does.


As compared to the Earth

16.) Saturn's atmospheric constituents are, in order by mass, hydrogen (88 percent) and helium (11 percent); and traces of methane, ammonia, ammonia crystals, and such other gases as ethane, acetylene, and phosphine comprise the remainder.

17.) The temperatures of Saturn's cloud tops are close to –176°C, about 27 degrees Celsius lower than such locations on Jupiter.

18.) Saturn’s rings are named in order of their discovery, and from the planet outward they are known as the D, C, B, A, F, G, and E rings.

19.) The Cassini probe discovered an additional faint ring between the G ring and the F ring in 2006.

20.) The main rings are now known to comprise more than 100,000 individual ringlets, each of which circles the planet.

21.) The visible rings stretch out to a distance of 136,200 km from Saturn's center, but in many regions they may be only 5 m (16.4 ft) thick.

22.) They are thought to consist of aggregates of rock, frozen gases, and water ice ranging in size from less than 0.0005 cm in diameter to about 10 m in diameter—from dust to boulder size.

23.) The apparent separation between the A and B rings is called Cassini's division, after its discoverer, the French astronomer Giovanni Cassini.

24.) Saturn has at least 62 moons that range up to 2,575 km in radius and consist mostly of the lighter, icy substances. Only 53 have formal names. There are also hundreds of moonlets on the planet’s rings.

25.) Twelve moons of Saturn were discovered in 2005, 9 moons were discovered in 2006 and 4 moons were discovered in 2007.



26.) The five larger inner satellites of Saturn are Mimas, Enceladus, Tethys, Dione, and Rhea. These moons are roughly spherical in shape and composed mostly of water ice and are heavily cratered by meteorite impacts.

27.) The outer satellites of Saturn are Hyperion and Iapetus. These satellites also consist mainly of water ice.

28.) Phoebe, the farthest large satellite, moves in a retrograde orbit (in the opposite direction of the orbits of most of the other satellites) that is at a sharp angle to Saturn's equator.

29.) Saturn’s largest moon is the Titan. It orbits the planet between the inner and outer satellites and has a radius of 2,575 km.

30.) Titan is larger than the planet Mercury and features large rock-like objects probably made of ice.

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Friday, October 21, 2011

50 Interesting and Amazing Facts About the Sun


The sun is the most important object in our solar system. Here are some fascinating and interesting facts about this heavenly object.

1.) The Sun is the closest star to Earth. It is located at the center of the Solar System.

2.) This huge mass of hot, glowing gas has strong gravitational pull that holds Earth and the other planets in the solar system in orbit.

3.) The light of the Sun and its heat influence all of the objects in the solar system and allow life to exist on Earth. Without the sun, there is no life.

4.) The Sun is an average star. It is one of the hundreds of billions of stars in the Milky Way with medium range in size, age, and temperature.

5.) Milky Way, which contains about 400 billions of stars, is just one of more than 100 billion galaxies in the observable universe.  


6.) The beautiful and useful Sun is 4.6 billion years of age and will continuously shine for the next 7 billion years.

7.) Beautiful as it is, the sun is also harmful to humans. It can cause skin cancer and can damage the eyes when directly look at even with sunglasses or during an eclipse.

8.) The Sun is large and massive object with a radius of 695,508 km which is 109 times as large as Earth’s radius.

9.) A million Earths could fit inside the Sun if it is a hollow.

10.) The Sun has a mass of 1.989 x 1027 metric tons or 1,989,000,000,000,000,000,000,000,000. That is 1,989 followed by 24 zeroes.

11.) The Sun’s average density is only 1.409 g/cu cm, which is a quarter of the average density of Earth.

12.) The Sun is 333,000 times as large as our Earth.

13.) The Sun generates 3.83 x 1026 watts of power in the form of light. In comparison, an incandescent lamp emits 60 to 100 watts of power.

14.) The temperature of the outer, visible part of the Sun is 5500°C.

15.) The average distance of the Sun from the Earth is 150 million km. The distance is so great that the Sun appears small when viewed from the planet.



16.) Due to the huge distance, it takes 8 minutes for the light from the Sun to reach Earth.

17.) Proxima Centauri is the Sun’s nearest stellar neighbor. It is 4.3 light-years from our solar system, meaning light from Proxima Centauri takes 4.3 years to reach the Sun.

18.) This great distance between the Sun and Proxima Centauri is equivalent to 30 trillion kilometers which is impossible for humans to reach.

19.) The Sun is so much closer to Earth than all other stars are that the intense light of the Sun keeps us from seeing any other stars during the day.

20.) The Sun is a second-generation star, meaning that some of its material came from former stars.

21.) Some stars in our galaxy are nearly as old as the expanding universe which is about 14 billion years old.

22.) The main ingredient of the Sun is hydrogen. It also contains heavier elements, such as carbon, nitrogen, and oxygen.

23.) The Sun is located in the outer part of the Milky Way galaxy, at a distance of 2.6 x 1017 km from the center.

24.) The Sun moves with great speed around the center at a velocity of 220 km/s, takes 250 million years to complete one trip around the center of the Milky Way galaxy.

25.) The Sun has circled the Milky Way galaxy more than 18 times during its 4.6-billion-year lifetime.



26.) The largest accurately determined stellar mass is of a star called V382 Cygni. This gigantic star is 27 times that of the Sun.

27.) The apparent magnitude of the Sun is -26.72. The apparent magnitude of the brightest star in Earth’s night sky, Sirius, is -1.46. Stars with negative magnitudes are the brightest of all.
28.) The Sun’s absolute luminosity is 3.86 x 1026 watts.

29.) After 3 billion years from now, the Sun will be hot enough to boil Earth’s oceans away.
30.) Four billion years thereafter, the Sun will have used up all its hydrogen and will balloon into a giant star that engulfs the planet Mercury.
31.) After 7 billion years from now, the Sun will be a red giant star. It will then be 2,000 times brighter than it is now, and hot enough to melt Earth’s rocks.
32.)  At this time the outer solar system will get warmer and more habitable. The icy moons of the giant planets may warm enough to be covered by water instead of ice.
33.) About 8 billion years from now, the Sun will become a white dwarf star and after it becomes a white dwarf, it will cool slowly for billions of years, eventually becoming so cool that it will no longer emit light.

34.) In just one second the Sun emits more energy than humans have used in the last 10,000 years.

35.) The visible part of the Sun is called the photosphere.



36.) The Earth and the Sun both rotates from west to east when viewed from above the North Pole, but unlike Earth, different parts of the Sun rotate at different rates

37.) A spot at the Sun’s equator takes 25 days to rotate completely, while a spot 15° from the poles takes 34 days to make a complete rotation.

38.) Sunlight appears yellowish, but it is actually a combination of a rainbow of colors.

39.) Red has the longest wavelength of visible light, and violet has the shortest.

40.) The corona is the very hot layer of the solar atmosphere above the chromospheres

41.) The chromosphere and photosphere are closer to the Sun’s core than is the corona, but the corona is several hundred times hotter than the chromosphere and photosphere.

42.) The chromosphere is a thin layer about 2,000 to 3,000 km (about 1,200 to 1,900 mi) thick, just above the visible photosphere.

43.) The biggest sunspots exceed Earth in size and are easily visible with a telescope. Sunspots rotate with the Sun and change in size and shape. They come and go, with lifetimes lasting from hours to months.

44.) The Greek philosopher Aristotle was the first known person to use a device that allowed indirect observation of the Sun.

45.) Galileo was the first person to use telescope in conducting observation of the Sun.



46.) During a total solar eclipse, the solar corona can be seen with the naked eye, during the brief period of totality.

47.) A solar eclipse as viewed on Earth occurs when the Moon passes between the Sun and the Earth.

48.) There are two types of solar eclipse – partial and total. The next partial eclipse will occur on November 25, 2011 and the last partial eclipse was on July 1, 2011.

49. The last full solar eclipse occurred on July 11, 2010 and the next total eclipse will be on November 13, 2012.

50.)  Solar eclipses can occur up to 5 times per year and since 1582, the years 1693, 1758, 1805, 1823, 1870, and 1935 have had five solar eclipses. The next occurrence will be 2206.

See also

Saturday, October 15, 2011

65 Interesting and Scientific Facts About the Planet Mars


One of the most popular planets in our solar system is the planet Mars. This planet is of special scientific interest and the subject of extensive research due to its similarities to Earth.

Here’s a long list of amazingly interesting facts about Mars.

1.) This planet is named for Mars, the Roman god of war – the equivalent of the Greek’s Ares.

2.) Mars is the 4th planet in distance from the Sun in the solar system.

3.) Mars is sometimes called the “red planet” because it appears fiery red in Earth’s night sky.

4.) If you will view Mars using a telescope, it looks like a reddish-orange disk.

5.) Mars has an atmosphere with seasons and changing weather, and its surface shows evidence of ancient water and volcanoes.



6.) The length of day in Mars and the tilt of its axis are similar to those of Earth.

7.) Mars takes about two years to circle the Sun at an average distance of 228 million km.

8.) The possibility of life on Mars is one of the major questions in astronomy.

9.) There are more space probes that have been sent to Mars than to any other planet.

10.) The red color of Mars is the result of rusty, iron-oxide mineral dust that covers the planet’s surface.

11.) The color of the sky on Mars during mid-day is reddish to pink because scattering of red light by fine dust particles.

12.) The color of the sky in Mars when the Sun is low is blue. The pinkish mid-day skies give way to bluish sunsets.

13.) Mars is a small planet with a diameter of about 6,794 km or about half the diameter of Earth.

14.) Mars has about one-tenth Earth’s mass.

15.) The force of gravity on the surface of Mars is about three-eighths of that on Earth.



16.) Mars has twice the diameter and twice the surface gravity of Earth’s Moon.

17.) The surface area of Mars is almost exactly the same as the surface area of the dry land on Earth.

18.) Mars is about the same age as Earth, having formed from the same spinning, condensing cloud of gas and dust that formed the Sun and the other planets about 4.6 billion years ago.

19.) Mars has two moons named after the sons of the Roman god Mars – Phobos and Deimos.

20.) Phobos orbits Mars once in less than one Martian day, so it appears to rise in the west and set in the east, usually twice each day.

 21.) Deimos has the more ordinary habit of rising in the east and setting in the west.

22.) Mars appears as a fairly bright, red, star-like object in Earth’s night sky.

23.) As Mars and Earth orbit the Sun, the distance between them varies from about 56 million km at their closest approaches to about 375 million km when the planets are on opposite sides of the Sun.

24.) In late August 2003 Earth and Mars passed closer to each other than at any time since 1924. The two planets will not get that close again until the year 2287.

25.) When Mars is close to Earth, an observer with a telescope can usually see white ice caps at the north and south poles of Mars.



26.) These polar caps grow and shrink throughout the Martian year, just as the polar caps of Earth do.

27.) The darker areas of Mars’s surface look greenish through the telescope but this is an optical illusion caused by the contrast in color between the dark patches and the redder, brighter areas.

28.) Mars dark areas are regions of relatively unweathered dark rocks and sand, while the bright areas are regions with deposits of dusty, fine-grained oxidized iron minerals.

29.) The “canals” that people observed on Mars during the 19th century are actually another optical illusion, caused by the mind’s tendency to draw connections between irregular patches in a fuzzy image.

30.) Mars’s orbit is more elliptical than Earth’s—its nearest point to the Sun (perihelion) is about 42 million km closer than its farthest point (aphelion), compared with only a 5 million km  difference between perihelion and aphelion for Earth.

31.) Mars’s year, or the time it takes to revolve once around the Sun, is about two Earth years long (687 Earth days).

32.) Mars receives less than half the amount of sunlight Earth does and is much colder.

33.) Mars is tilted on its axis by about 25° (Earth is tilted at 23.5°). This tilt gives Mars seasons similar to Earth’s seasons.

34.) The southern hemisphere’s summer on Mars is about 25 days shorter than the northern summer.

35.) Like Earth, Mars turns counterclockwise on its axis (from west to east) when seen from its North Pole and orbits the Sun in a counterclockwise direction.



36.) It takes Mars 24 hours and 37 minutes to rotate once on its axis (its sidereal day).

37.) Its solar day (the time between when the Sun next crosses the noon point in the sky) is about 24 hours and 39 minutes—its orbital motion around the Sun adds two minutes to its rotation period.

38.) The Martian solar day is sometimes called a sol.

39.) The density of Mars is about 30% less than that of Earth (3.94 g/cm3 vs. 5.52 g/cm3).

40.) The surface of Mars would be a harsh place for humans, but it is more like the surface of Earth than that of any other planet.

41.) The temperature on Mars never gets much warmer than the temperature at Antarctica, and it is usually much colder.

42.) At the surface the average temperature is about -55°C and at the extremes it ranges from about -140° to 15°C.

43.) Hellas Planitia, a giant impact basin in the southern hemisphere, is 6 km deep and with a diameter of about 2,000 km making it the largest and deepest basin on Mars.

44.) The enormous bulge in Mars’ surface is called Tharsis. It is 10 km high and 4,000 km wide and contains giant volcanoes and valleys.

45.) Olympus Mons is the largest volcano in the solar system. It is located in the Tharsis region and is more than 21 km in height.


Olympus mons

46.) This volcano is more than twice as high as Earth’s Mount Everest with an area as wide as Arizona, USA.

47.) Three other large volcanoes are located near Olympus Mons. These are Arsia Mons, Pavonis Mons, and Ascraeus Mons.

48.) Alba Patera is another volcano located on the Tharsis bulge. It is less than 6 km in height but has a diameter of more than 1,600 km.

49.) Valles Marineris, a great rift valley and interconnected canyon system, is the most notable stress feature associated with the Tharsis bulge. It was named for the U.S. Mariner spacecraft that discovered it.

50.)  Valles Marineris is about the same length as the distance from New York to California (about 4,000 km.

51.) This canyon system reaches widths of 700 km and depths of 7 km in some places.

52.) Ares Vallis is one of the outflow channels of Mars. It is where the Mars Pathfinder spacecraft landed in 1997.

53.) Mars has small, permanent ice caps at its north and south poles that increase in size with the addition of seasonal ice caps during the winter of each hemisphere.

54.) A region of Elysium Planitia near the equator is a possible “frozen sea” covered in dusty soil or volcanic ash only a few centimeters thick.

55.) The atmosphere of Mars is 95% (CO2), nearly 3% nitrogen, and nearly 2% argon with tiny amounts of oxygen, carbon monoxide, water vapor, ozone, and other trace gases.


As compared to the earth

56.) The dust in Mars is not sandy, as in a sandstorm on Earth, but has the consistency of flour.

57.) Mars’ largest storms can cover the entire planet and last for months. Large sand storms were recorded in 1971, 2001 and 2007.

58.) Mars has “Dust devils” which are swirling columns of dust and sand that occur during the Martian summer that can reach heights of 10 km and rotate at 30 meters per second.

59.) Dust devils on Mars can be ten times as large as Earth tornados.

60.) Mars is a frozen, dry world. Its landscape is much like some of the cold, dry deserts of Earth with soils completely sterile.

61.) Mars environment is much too harsh for Earth-like organisms to survive.

62.) Mariner 9 was the first spacecraft to orbit Mars. It was launched in 1971.

63.) Mars Observer, launched in 1992 and Mars Global Surveyor, launched in 1996, both lost contact to Earth for unknown reason.

64.) Two spacecrafts that crashed on Mars – Mars Climate Orbiter reached the planet in September 1999 but crashed into Mars due to navigational error and Mars Polar Lander, reached Mars in December 1999, but it too crashed into the planet’s surface.

65.) NASA launched the Mars Reconnaissance Orbiter in August 2005, and it successfully went into orbit around Mars in 2006. The Mars Reconnaissance Orbiter has the most powerful camera ever sent to another body in space.


Victoria Crater

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Thursday, October 6, 2011

40 Interesting and Scientific Facts About The Planet Uranus | Scienceray

40 Interesting and Scientific Facts About The Planet Uranus | Scienceray 


Uranus is one of the largest planets in the Solar System.

Here’s a list of interesting and educational tidbits about the planet Uranus.

1.) The planet Uranus is named after the god of the heavens in Greek and Roman mythology – Uranus, the father of Saturn and the grandfather of Jupiter.
2.) Uranus is the 7th planet in distance from the Sun and the 3rd largest planet in diameter, and 4th largest in mass in the solar system.
3.) Uranus is peculiar among other major planets because it is tipped sideways on its axis of rotation.
4.) This planet experiences extreme seasons.
5.) Uranus has 13 rings and 27 known moons.


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Monday, September 19, 2011

40 Amazing and Interesting Scientific Facts About the Planet Mercury

Mercury is the closest planet to the sun in the solar system. Here are some scientific and interesting facts about this planet.

1.) Mercury was named for the fleet-footed messenger of the gods in Roman mythology – the equivalent of the Greek’s Hermes.


2.) Mercury is the first planet in distance from the Sun in the solar system. It is the smallest of the 8 planets.

3.) This planet is the smallest of the rocky or terrestrial planets. The others are Venus, Earth, and Mars.

4.) Mercury is the only rocky planet other than Earth to have a global magnetic field, which is about 1% as strong as Earth’s.

5.) Like Venus, Mercury has no moons of its own.



6.) Although it is the nearest planet to the Sun, it is only the second hottest planet. Venus is the hottest.

7.) Mercury circles the Sun every 88 Earth days at an average distance of 58 million km and takes 59 days to turns on its axis.

8.) Mercury’s diameter is 4,879 km, about 40% the diameter of Earth or about 40% wider than the Moon.

9.) Mercury’s volume and mass are about one-eighteenth that of Earth.

10.) Mercury’s mean density, 5.4 g/cm³, is nearly as great as that of Earth and is higher than that of any of the other planets.

11.) The force of gravity on the planet’s surface is about 1/3 of that on Earth’s surface or about twice the surface gravity on the Moon and about the same as the surface gravity on Mars.

12.) Jupiter’s moon Ganymede and Saturn’s moon Titan are larger than Mercury but are much less dense.

13.) Mercury orbits the Sun every 87.97 Earth days at an average distance of approximately 58 million km.

14.) Mercury’s orbit is highly elliptical and ranges from 46 million km at its nearest point to the Sun (perihelion) to 69.8 million km at its farthest point (aphelion).

15.) As a result, sunlight is over 2.3 times stronger at perihelion than at aphelion.



16.) At a single orbit, Mercury receives as much as 11 times the intensity of sunlight that Earth does to a minimum of about 4.5 times.

17.) Mercury’s orbital velocity is also about 46 percent faster at perihelion than at aphelion. The planet’s orbit is tilted 7 degrees to the plane in which Earth orbits around the Sun.

18.) When viewed from North Pole. Mercury turns counterclockwise (west to east) like Earth and most other planets.

19.) Earth’s axis is tilted 23.5° while Mercury’s axis is almost perfectly vertical. Because its axis is vertical, like Venus, Mercury does not have seasons.

20.) Mercury rotates only once every 58.65 days, 2/3 of its period of revolution around the Sun.

21.) A complete solar day on Mercury lasts 175.84 Earth days, or two of Mercury’s years, and a night and a day at the equator each last one Mercurian year or 87.97 Earth days.

22.) Mercury preserves a record of a violent early period when asteroids, comets, and other debris bombarded the newly formed planets.

23.) The craters on Mercury are shallower than those on the Moon.

24.) The largest geological feature on Mercury is the Caloris Basin. It is the result of a massive ancient impact.

25.) Mercury’s surface is crisscrossed by long escarpments or cliffs.



26.) Mercury is a poor reflector of sunlight because its surface consists of dark, dry soil called regolith created by micrometeorite impacts over billions of years.

27.) The planet’s albedo, or the amount of sunlight it reflects, is only about 12 percent, about the same as our Moon.

28.)  Surface temperatures on Mercury can be as hot as 650°C.

29.) Mercury’s side facing the Sun gets very hot—up to 450°C—while the side facing away quickly cools to frigid temperatures, -183°.

30.) The floors of craters at the north and south poles receive very little sunlight and always remain extremely cold—about -200°C.

 31.) Mercury’s equatorial region experiences extreme changes, reaching 450°C at perihelion when facing the Sun—hot enough to melt zinc.

32.) In 1991 powerful radio telescopes on Earth revealed signs of possible deposits of ice in the polar regions of Mercury.

33.) These ice deposits occur in areas where sunlight never falls, such as crater bottoms near both of the planet’s poles.

 34.) The ice on Mercury likely comes from comets or water-bearing meteorites that have hit Mercury over the planet’s history up through the present.

35.) Scientists use a technique called spectroscopy to conduct studies of the light that Mercury reflects.



36.) These studies indicate that planet has only an extremely thin atmosphere, containing sodium and potassium.

37.) The first up-close study of Mercury came with National Aeronautics and Space Administration (NASA)’s Mariner 10 spacecraft, which passed Mercury twice in 1974 and once in 1975.

38.) It sent back pictures of a moonlike, crater-pocked surface. The spacecraft also detected a magnetic field and provided data about the planet’s density and some of its surface chemistry.

39.) In 2004, NASA launched a much more ambitious mission to Mercury – the so-called MESSENGER- MErcury Surface, Space ENvironment, GEochemistry, and Ranging.

40.) MESSENGER is set to enter orbit around Mercury in 2011. The first orbital image of Mercury was obtained on March 29, 2011.

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