Know More..

Category Astronomy

Which planet has more than 1,600 major volcanoes across its surface?

There are more volcanoes on Venus than on any other planet in the solar system. Astronomers know of more than 1,600 volcanoes on its surface, but there are likely many more too small for us to see. Scientists think most of these are dormant, though a handful may still be active.

Even though there are over 1,600 major volcanoes on Venus, none are known to be erupting at present and most are probably long extinct. However, radar sounding by the Magellan probe revealed evidence for comparatively recent volcanic activity at Venus’s highest volcano Maat Mons, in the form of ash flows near the summit and on the northern flank. Although many lines of evidence suggest that Venus is likely to be volcanically active, present-day eruptions at Maat Mons have not been confirmed. Nevertheless, other more recent studies, in January 2020, suggests Venus is currently volcanically active.

In 2020, a study by University of Maryland supported by Swiss National Science Foundation and NASA discovered that 37 of Venus coronae show signs of ongoing activity. Maryland professor Laurent Montesi said, “we are able to point to specific structures and say ‘Look, this is not an ancient volcano but one that is active today, dormant perhaps, but not dead…” The active coronae are clustered near each other, so positioning geologic survey instruments would now be easier.

 

Picture Credit : Google

Why three major telescopes hit the headlines in 2020?

China’s Five-hundred-metre Aperture Spherical Radio Telescope (FAST) passed national evaluation and officially began operation in January 2020. With a dish the size of 30 football fields, it is the world’s largest single-dish radio telescope and the most sensitive listening device. The single-dish radio telescope is made of 4,450 individual panels.

The facility will help scientists learn more about the Universe’s early days, detect low-frequency gravitational waves and hunt for signals that may have been produced by distant alien civilizations.

  • NASA’s Spitzer Space Telescope was retired in January 2020. Launched in 2003, Spitzer studied the universe in infrared light, revealing wonders of the Solar System, our galaxy, and beyond. Among its many scientific contributions, Spitzer studied comets and asteroids in the Solar System and found a previously unidentified ring around Saturn.
  • In April 2020, the Hubble Space Telescope completed 30 years of service. Perched on the low Earth orbit, the telescope’s modest 2.4-metre mirror continues to give us an unprecedented window on the Universe. Thanks to Hubble and the Gaia space observatory, we were able to calculate the age of our Universe, which is approximately 13.8 billion years old. From observations from Hubble, we also learnt that black holes are at the centre of almost every major galaxy.

Did you know?

  • NASA’s James Webb Space Telescope (JWST) is scheduled to be launched in October 2021. While it is touted as the successor of the Hubble Space Telescope, some scientists believe the two telescopes are actually complementary. Hubble has limited capabilities at near-infrared wavelengths, but it is best suited for observing in the ultraviolet and optical ranges of the light spectrum. Whereas James Webb is perfectly poised to study things in infrared range and these include formation of stars and planets, extremely distant galaxies, and even the atmospheres of exoplanets.
  • The Hubble’s mission ends in 2021, unless NASA decides to extend it.

 

Picture Credit : Google

What’s better than a powerful telescope?

Seeing for yourself in close-up – but it’s too dangerous and expensive to send astronomers deep into space. That’s why space probes are such important tools. Space probes are fitted with cameras. They beam back close-up photos of faraway planets and comets.

Amazing! Chandra is a billion times more powerful than the first X-ray telescope. If telescopes keep improving at this rate, we’ll be able to see the farthest edges of the Universe in 30 years’ time!

Is it true? A probe found a watery world.

Yes. The Voyager 2 probe photographed what might be water on Jupiter’s moon, Europa. If there is life out there, probes will probably find it first.

Could we build an observatory on the Moon?

The dark side of the Moon would be a perfect site. Always pointing away from the Earth, it is shielded from man-made X-rays. But building there would be very expensive.

Could we build Very Large Arrays in space?

Scientists are already testing a cluster of satellites that fly in perfect formation, using laser beams. The same technology will be used to create a string of small satellite telescopes, making one huge ‘eye’ in space.

Picture Credit : Google

Who made the first radio telescope?

Radio telescopes are like giant satellite dishes that pick up invisible radio waves and similar waves, instead of light rays. Unlike light, radio waves can travel through cloud, so radio telescopes can be built just about anywhere! An American called Grote Reber made the first one in the 1930s.

Amazing! A telescope can be 8,000 km long. The Very Long Baseline Array (VLBA) stretches across the USA. It has ten different dishes and produces the best-quality radio images of space from Earth yet!

Which are the most powerful radio telescopes?

The ones that are made up of several different radio dishes, such as the Very Large Array (VLA) in New Mexico, USA. The VLA has 27 dishes, each 25 metres across. Scientists compare the findings from all 27 dishes to get super-accurate results.

Where is the biggest radio telescope?

The world’s biggest single-dish radio telescope was built in Puerto Rico in the Caribbean about 40 years ago. It is 300 metres across – so it would take you more than ten minutes to walk around the edge of it.

Is it true? Only ten astronomers are allowed to use the VLA.

No. It is used by over 500 astronomers a year. Some study our near-neighbours in the Solar System, while others peer way beyond our galaxy to others in deepest space.

Picture Credit : Google

How deep is space?

Early astronomers thought that all the stars were the same distance from us, forming a simple shell around the Earth. Now we know that some stars are relatively close to us, and others are trillions of kilometres away.

Is it true? We measure how far the stars are in kilometres.

No. They’re so far away, that we use light years instead. A light year is how far light travels in one year – 9,461 billion km!

Are there candles in space?

Not really. But we can see how far away a galaxy is by the brightness of a special type of star, called a ‘standard candle’. The further away the galaxy, the dimmer the candle.

Amazing! Galaxies move so quickly they are different colours. The light waves from them change, just as a fire engine’s siren sounds lower after it zooms past. We use the colour to measure the galaxies’ speed.

How do you measure the distance to a star?

Watch the tip of your finger as you move it towards to your nose. The closer it gets, the more cross-eyed you become! Astronomers can tell the distance to a star by measuring how ‘cross-eyed’ a pair of telescopes has to be to see it.

Picture Credit : Google

Where do astronomers put their telescopes?

Observatories are buildings where astronomers go to look at the sky. They house the most powerful telescopes on Earth. The telescopes are usually kept in a room with a dome-shaped roof. Observatories have other instruments too, such as very precise clocks, to help keep accurate time and records.

Where’s the best place to build an observatory?

Where you’ll get the clearest view! Most are built away from city lights. Mountain-tops are best of all, because they poke above any clouds that might spoil the view.

How can a telescope see through the roof?

It doesn’t have to – an observatory’s domed roof is specially designed to slide open at night, so that the picture through the telescope isn’t distorted (blurred) by looking through a window. The telescope can be pointed at any place in the sky.

Amazing! The Ancient Babylonians used observatories. They did their star-gazing from stepped towers called ziggurats.

Is it true? The Greenwich Observatory houses the most telescopes.

No. The Kitt Peak National Observatory in Arizona, USA has the most optical telescopes. One of them, the Mayall Telescope, is 4 m across!

Picture Credit : Google

Who said that planets go round the Sun?

Nicolaus Copernicus explained this idea in a book in 1543. The problem was, the Church stated that God had put the Earth at the centre of the Universe. You could be put to death for saying that the Earth went round the Sun.

Who was put on trial for star-gazing?

Few scientists were brave enough to say that they agreed with Copernicus’s findings that the Earth went round the Sun. The Italian astronomer Galileo was – and was put on trial for his ideas in 1634.

Is it true? The Church accepted that Galileo was right in the end.

Yes. The Church eventually agreed that the Earth and other planets travelled round the Sun. But they didn’t do this until 1992 – 350 years after Galileo’s death!

Who first used a telescope for astronomy?

Galileo started making telescopes in 1609, not long after Lippershey made his. Galileo was the first person to realize how useful a telescope would be for looking at the night sky. Because he could see more clearly, he made lots of important new finds, such as discovering four of Jupiter’s moons.

Amazing! Copernicus explained the seasons. By showing that the Earth goes round the Sun and also spins at the same time, Copernicus explained why some times of the year are warmer than others.

Picture Credit : Google

Who made the first telescope?

Hans Lippershey, a Dutch man who made spectacles, probably made the first telescope in 1608. He noticed that if he put two lenses at different ends of a tube and looked through them, objects seemed to be nearer and clearer.

Is it true? Newton saw a rainbow in his telescope.

Yes. Isaac Newton noticed that the edges of objects seemed coloured when you looked through a telescope. That’s how he began to work out that clear white light is made up of many different colours.

How does a telescope work?

The lens (curved piece of glass) at the front end of a telescope gathers light to make an image of an object that is far away. The lens at the back magnifies the image so it can be seen more clearly.

Who put mirrors in a telescope?

Isaac Newton was the first person to make a mirror or reflecting telescope. He replaced the front lens with a dish-shaped mirror at the back. The mirror reflected the image on to a smaller mirror, and then into the eye.

Amazing! You can see Saturn’s rings through a telescope. Telescopes magnify images (make them bigger) so much that you can even make out Saturn’s faint rings – which are about 1.3 billion km away!

Picture Credit : Google

How did sailors know where they were going?

Out at sea, there are no landmarks. In the Middle Ages, sailors had special instruments that used the position of the Sun and stars to tell them where they were. These included compasses, astrolabes and cross-staffs.

Amazing! The first astrolabes were made 1,500 years ago! Indian and Arab astronomers used pocket-sized instruments called astrolabes in the AD 500s.

Is it true? Astrolabes only worked at night.

No. You could use the position of the Sun instead of the stars, when you were sailing during the day. You looked at its position compared to the horizon.

What is the pole star?

The only star which doesn’t appear to move is above the North Pole. Sailors could tell where they were by looking at the pole star – it’s lowest in the sky at the Equator.

How did an astrolabe work?

An astrolabe had two discs, one with a star map, and the other with measuring lines and a pointer. You compared them with the Sun or a star and the horizon to work out your position.

Picture Credit : Google

Who first wrote about the stars?

The Babylonians were the first to write down their findings from studying the stars – around 5,000 years ago! They noticed that stars seem to form patterns, which we call constellations. The Babylonian empire was roughly where Iraq is today.

Is it true? The Babylonians were maths wizards.

Yes. At first their findings about the night sky were based on looking and guessing. By around 500 BC, the Babylonians used sums to predict exactly when events such as eclipses would happen.

How do we know about the first astronomers?

The Babylonians didn’t write on paper like we do. They wrote on clay tablets, so fragments have survived. Scientists called archaeologists dig in the ground for clues about ancient peoples such as the Babylonians.

Amazing! The Babylonians didn’t see the same night sky as us. There were no twinkling satellites, and the stars were in different places because our Solar System has moved since then.

What was a Babylonian year like?

The Babylonians worked out a 12-month year. Each month began with the first sight of the crescent Moon. The months were called Nisannu, Ayaru, Simanu, Du’uzu, Abu, Ululu, Tashritu, Arahsamnu, Kislimu, Tebetu, Shabatu and Addaru.

Picture Credit : Google