My Science School

 

 

 

Which astronomer conclusively proved that the Sun was the centre of the Solar System?

Nicolas Copernicus, the Polish astronomer, studied optics, mathematics, perspective and canon law. Appointed canon in 1497, he studied medicine and worked as a medical attendant until 1512. He completed his book De Revolutionibus Orbium Coelestium; he proved that the Sun was at the centre of the Solar System, in 1530. His heliocentric theory was bitterly opposed.

 

 

 

 

 

 

 

 

 

What was the name of the astronomer who discovered the laws governing the movement of the heavenly bodies?

Johann Kepler, German astronomer and professor of mathematics, who later studied astronomy and worked with Tycho Brahe. He first published his views on the universe in 1596. His analysis of Tycho’s observations of the planets led him to discover “Keplers’ Laws”.

With these fundamental laws, Kepler gained immortal fame. But he could not adequately explain why the planets behaved in this way.

 

 

What was the contribution of Pierre Laplace, the French Astronomer and Mathematician, to the science of astronomy?

Pierre Laplace is famous for his application of applied mathematics to practical astronomy. He published his work Mecanique Celeste in the years 1799-1825. It was an attempt to explain the mechanical problems presented by the Solar System.

 

 

 

 

 

 

Name the astronomer who is acclaimed as the father of modern practical astronomy.

John Flamsteed, first Astronomer-Royal of England. In 1676, when Greenwich Observatory was built, he began observations which really began modern practical astronomy. The first reliable catalogue of fixed stars was compiled by him, and he wrote the great book Historia Coelestis Britannica, published in 1725. His work supplied the background for some of Newton’s theories.

 

 

 

 

 

What are lunar faults and ridges?

Lunar faults and ridges are similar to those on earth. One fault called strangely the Straight Wall is some 200 km long and about 300 m high. Lunar ridges run for hundreds of kilometers and may even form complex branch ridges.

 

 

 

 

 

 

 

 

 

 

 

What are the lunar walled plains?

Walled plains are lunar craters which are so vast that they resemble plains surrounded by circular walls of mountains. One of the walled plains, Clavius, is large enough to contain the whole of Switzerland within it.

 

 

What is known as the “Monarch of the Moon”?

The crater Copernicus has been nicknamed “Monarch of the Moon” due to its impressive features. The crater is about 90 km in diameter and is surrounded by mountain walls about 6,000 m high. The inner mountain walls around Copernicus are also not uniformly sloping but terraced, as if the original lava lake in its centre had receded in discrete stages.

 

 

 

 

 

 

 

 

What are lunar domes?

Lunar domes are small convex swellings on the Moon.

How did lunar domes originate?

Lunar domes are possibly large solidified bubbles of lava.

 

 

 

 

 

 

 

 

What are crater chains?

Sometimes crater-lets occur in linear series which gives the impression that it is a cleft. The Huygens cleft, for example, is not a genuine cleft but actually a crater chain.

 

 

 

 

 

 

 

 

 

What are lunar rays?

Lunar rays appear as lines, more or less straight, drawn on the surface of the Moon. They are also called bright rays since they usually appear as brilliant white streaks. The rays however become invisible when close to the terminator.

Also, the rays are not continuous and when observed closely are seen to possess a definite structure. How they came to be formed has however still not been satisfactorily explained.

 

 

 

 

Continue reading "The Moon"

 

 

 

What are ruined lunar craters?

Ruined craters are ones that have been formed in the early stages of the Moon’s history but have been devastated subsequently by later volcanic eruptions and crustal disturbances. The outlines of some of the heavily ruined craters are barely recognizable.

 

 

 

 

 

 

 

What are lunar clefts?

A lunar cleft has the appearance of a river bed on Earth. This is a mere coincidence since there is no water on the Moon and appearances can be deceptive. One of the impressive clefts, the great Heroclotus Valley clefts, is 500 m deep and winds impressively like a river gorge across the plain.

 

 

 

 

 

Where did the first moon craft “Eagle” land?

“Eagle” landed on Mare Tranquillitatis (the sea of tranquility) at a spot appropriately named “Tranquillity Base”.

 

 

 

 

 

 

 

 

 

What are crater lets?

Craterlets are tiny craters ranging in diameter from a few meters to about twenty kilometers. The Moon has plenty of such crater lets.

 

 

 

 

 

 

 

 

 

What are twin craters?

Twin craters are those that occur close together, sometimes separated and sometimes joined together. In some cases, one crater crosses the boundary of another crater causing damage to it. Since large craters have been formed earlier, it is usually the small ones formed later which intrude and do the damage.

How deep are lunar craters?

Lunar craters can be several kilometers deep. The crater Newton near the South Pole is so deep that it could almost accommodate Mount Everest, the highest mountain on Earth.

What are lunar craters actually?

Lunar craters are circular in shape with raised walls and sunken floors. They are not the conventional type of craters and are more in the nature of walled depressions.

How large are lunar craters?

Lunar craters vary vastly in size from tiny craters to huge walled plains hundreds of kilometers wide.

How were the lunar craters formed?

It is believed the lunar craters were formed partly by volcanic action (when part of the inside of the Moon was still liquid many millions of years ago), and partly due to meteor impacts later.

 

 

 

 

What is the Linne Crater mystery?

There is recorded evidence of a crater named Linne estimated to be about 10 km across and about 300 m deep. The last record of Linne was in 1843. However, an observation in 1866 revealed that there was virtually no evidence of Linne. Between 1843 and 1866, Linne had apparently just vanished. No satisfactory explanation is available.

 

Mare Crisium                        Sea of Crises.

Mare Fecunditatis                 Sea of Fecundity.

Mare Nectairs                        Sea of Nectar.

Mare Tranquillitatis               Sea of Tranquility

Mare Serentitatis                    Sea of Serenity

Mare Frigoris                          Sea of Cold.

Mare Imbrium                         Sea of Showers.

Mare Vaporum                         Sea of Vapors.

Mare Nubium                            Sea of Clouds.

Mare Humorum                         Sea of Humors.

 

 

How high are the mountains on the Moon?

Lunar mountains are mainly found in the southern part of the Moon. The highest lunar mountains are higher than the mountains on Earth.

How is the height of lunar mountain measured?

The height of the lunar mountains can be estimated by studying the type of lighting and the shadows cast by the almost mountains at the terminator and mathematically analyzing them.

 

What are the lunar seas?

The lunar seas refer to the vast dark plains on the Moon. There is no water on the Moon and the name “Seas” is therefore a misnomer.

How are the lunar seas named?

Seas in Latin are “Mare” (pronounced “Mahri”) and its plural is Maria (pronounced “Mah-ri-ah”). Lunar seas are denoted by the word Mare followed by the Latin name for each sea.

Is there any significant difference between the near side of the Moon and the far side?

Yes. The far side of the Moon does not have any “Seas” like in the near side.

 

 

 

 

 

 

Why is the last quarter of the Moon less brilliant than the first quarter?

In the last quarter the eastern portion of the Moon is shining. Since no bright seas cover most of this portion, the last quarter is less bright than the first quarter.

 

What is the lunar limb?

The lunar limb is the Moon’s apparent edge as seen from the Earth.

Does the limb remain in the same position on the Moon’s disc?

Yes. The limb remains in more or less the same position on the Moon’s disc except for very minor shifts due to perturbations.

What is the terminator?

The terminator is the boundary between the day and night sides of the Moon.

Does the terminator remain stationary?

No. The terminator sweeps right across the Moon’s disc, once when the Moon is waxing (called morning terminator) and again when the Moon is waning (called evening terminator).

Why is the terminator important for studying features on the Moon’s surface?

The terminator does not appear as a smooth line, due to the unevenness of the Moon’s surface. At the morning terminator line when the Sun has just started rising, the peaks of the mountains which catch the first rays of the sun are brightly lit while the valleys are still in shadow. A study of the lights and shadows at the terminator therefore can provide a valuable insight into the topography of the lunar terrain.

What are the main parts of a lunar map?

Basically two maps of the Moon are used, one representing the near side and another representing the far side of the Moon.

How many features on the surface on the Moon have been recorded?

Over 100,000 features on the surface of the Moon have been recorded but many are not of importance and only the large ones are visible to the naked eye.

 

 

 

 

 

 

 

What are the different types of features visible on the Moon’s surface?

Some of the important features on the Moon’s surface are seas, mountains, valleys, peaks, domes, faults, ridges, craters, walled plains, small craters, ruined craters, twin craters, crater lets, plateaus, clefts, crater chains, rays, etc.

 

What is a solar-sail spacecraft?

A solar-sail spacecraft employs a large sail just like a sailing ship. However, the wind that strikes the sail and provides thrust to the spacecraft is not the normal wind but the solar wind. Hence, the spacecraft exploits the tiny force generated by the solar radiation, when it is reflected off a surface.

That solar radiation reflected by a surface exerts pressure is well known, but the pressure is too weak to be of any practical use on Earth. In space, where Earth’s gravity is negligible, solar sails can be used to propel a spacecraft.

A spacecraft designed by a group of universities and companies in Europe has a solar sail 100 meters long 100 meters wide made of aluminum coated mylar as thick as a human hair.

When solar radiation is reflected from the sail, it will generate a thrust of 0.08 Newton (one Newton is the force that will accelerate one kg of mass by one metre).

Computer simulation studies have shown that this craft would complete the lunar fly-by mission in about 700 days by always keeping the reflecting surface of the sail pointed towards the Sun.

This European spacecraft will also have a payload of 80-kg of scientific instrumentation.

 

Arthur C. Clarke, who predicted the use of synchronous satellites, also predicted the use of solar-sail spacecraft. Name his science fiction story.

“The Wind from the Sun”.

 

What is the ESA space sail contest?

The European Space Agency (ESA) has announced the first race in spaced open only to solar- sail spacecraft.

The winner of the “Space Sail Cup” will be the first craft that makes a loop around the Moon, flies into deep space and gets as close as 10,000 km to the planet Mars.

Launching of the spacecraft will be done free of cost by Ariane rocket. After reaching the high Earth orbit, the spacecraft must exclusively exploit the weak thrust of the solar radiation to escape the Earth’s gravity and, after a lunar fly-by, reach an interplanetary orbit around the Sun heading towards Mars.

The solar-sail spacecraft is nominally expected to make the lunar fly-by in two years and arrive near Mars in less than three and half years.

How many persons have walked on the Moon as part of the Apollo missions?

Twelve persons (all American astronauts) have walked on the Moon as part of the Apollo missions. They are:

 

Apollo 11 – Neil Armstrong, Edwin Aldrin.

 

Apollo 12 – Charles Conrad, Alan Bean.

 

Apollo 14 – Alan Shepard, Thomas Mitchell.

 

Apollo 15 – David Scott, James Irwin.

 

Apollo 16 – Charles Duke, John Young.

 

Apollo 17 – Eugene Cernan, Harrison Schmitt.

 

Continue reading "ARTIFICIAL SATELLITES AND SPACE TRAVEL"

 

 

 

When did man first land on the Moon?

On 20 July 1969, the lunar module “Eagle” (launched from the spacecraft Apollo 11) landed on the Moon, carrying two astronauts.

 

 

 

 

 

 

 

 

 

 

What was the first message from the Moon?

Immediately after Eagle landed, the astronauts sent the message “The Eagle has landed”.