What moons did Galileo discover in 1610?

Many years ago, in 1610, Italian astronomer Galileo Galilei discovered the first moons beyond Earth. Those were the moons of the planet Jupiter, the largest planet in the solar system.

Planet Jupiter has 80 moons. There are many interesting moons orbiting the planet, but the ones of great interest to us on a scientific level are the first four moons discovered called the Galilean satellites. They are lo, Europa, Ganymede, and Callisto. Here we look at the four largest moons of Jupiter.

What is a Moon?

Moons are those celestial bodies that orbit planets and asteroids in the solar system. They are also called natural satellites. The Earth has one moon, whilst the solar system has more than 200 moons. Most of the major planets except Mercury and Venus have moons.

Jupiter and Saturn have the most moons. Four of Jupiter's moons are named after Galileo Galilei who first discovered them.

And how were the Galilean moons formed? According to scientists, the moons were formed out of the dusty disc left after Jupiter was formed.

lo

The most volcanically active body in the solar system, lo has its surface enveloped by sulfur. Jupiter's gravity causes "tides" that rise some 100 metres high on lo and lead to the generation of heat for volcanic activity.

Europa

Europa's surface is covered mostly by water ice. This moon is considered to have twice as much water as Earth.

Ganymede

The largest moon in the solar system, Ganymede is the only moon that has its own internally generated magnetic field. Did you know that this moon is even larger than the planet Mercury?

Callisto

The second largest moon of Jupiter, Callisto's surface is highly cratered and ancient. This moon is about half rock and half ice.

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What was invented in 1888 by George Eastman?

On September 4, 1888, American inventor George Eastman received a patent for "new and useful improvements" in cameras. On that same day, Eastman also registered the trademark for the name Kodak, a word now synonymous with photography.

What do you, or anyone for that matter, do when you need to capture a moment? You pick up a smartphone, open the camera app, try to best fit the moment you are capturing inside the frame, and tap on the button on the screen to click a photograph. It is as simple as that. With more and more people carrying smartphones these days and with even the basic models boasting a decent camera, amateur photography has been revolutionised like never before.

The first such massive change that promoted amateur photography on a large scale came about in 1888 with the advent of the first Kodak camera. A simple box camera pre-loaded with a 100-exposure roll of film, it made photography less cumbersome than ever before. The man who made it possible was American inventor George Eastman.

Born in 1854 in upstate New York, Eastman had humble beginnings. His father's death meant that he had to drop out of high school while still a teenager in order to support his family. Starting out as a messenger boy earning $3 a week, he went on to be hired as a junior clerk earning $15 a week at the Rochester Savings Bank in 1874.

The trip that didn't happen

It was in that same year that he was drawn towards photography. When he made travel plans, a colleague suggested that Eastman record his trip using a "photographic  outfit”. Even though he eventually didn't make the trip, Eastman had purchased the "outfit and described it as "a pack-horse load”.

Apart from the fact that the camera was heavy and needed a tripod, Eastman would have also had to carry a tent and loads of equipment to develop the photographs if he had gone on the trip. Soon, Eastman was obsessed with the idea of making photography easier.

A company is born

Still holding on to his job at the bank, Eastman spent countless evenings and nights toiling away towards a solution. Realising that wet plates definitely weren't the way forward, Eastman invented and patented a dry plate formula. He went into the photographic business on a full-time basis, and the Eastman Dry Plate and Film Company was born.

More innovations followed as he began to look for new exposure methods. In order to replace the glass plates, he first came up with a light-sensitive, gelatin-coated paper that could be rolled onto a holder.

In 1888, Eastman introduced the first Kodak camera, which proved to be the first successful roll-film hand camera that came in a compact box with 100 exposures' worth of film. As the paper proved problematic, Eastman, along with young research chemist Henry  Reichenbach, experimented further until they hit upon the possibility of flexible rolls of sensitised celluloid. At around the same time, another American Hannibal Goodwin independently arrived at celluloid-based camera films, resulting in lengthy patent wars between the parties that was belatedly settled in Goodwin's favour.

On September 4, 1888, just months after the public release of the camera, Eastman received a patent for "new and useful improvements" in cameras. That very day. Eastman also registered the trademark for the Kodak name.

"We do the rest"

Bolstered by the introduction of the film rolls, the Kodak cameras became a runaway success. An advertising campaign was introduced with the slogan "You press the button, we do the rest." This was exactly how things panned out as users sent the entire camera back to the manufacturer for developing, printing, and reloading once the film was entirely used up.

Quick to spot an opportunity, Eastman changed the name of his company from Eastman Dry Plate and Film Company to Eastman Kodak Company in 1892. By the time he died aged Eastman Kodak dominated the industry in the U.S. and across the world. It still remains one of the best recognised names in the field, with the word Kodak becoming synonymous to photography.

Apart from being an inventor and innovator, Eastman was also far ahead of his time in various other ways. As a philanthropist, Eastman gave away much of the fortune that he created while still alive to many beneficiaries, including universities. As a businessman, he was among the first to introduce profit sharing as an incentive to employees. But then, he will forever be remembered as the one who placed the power of photography within the grasp of anyone who could just press a button. That button is now more accessible than ever before.

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What did Wilhelm Roentgen discover that helped with surgery?

Discovered in 1895 by German physicist Wilhelm Roentgen, X-ray revolutionised the fields of physics and medicine.

An X-ray is a kind of electromagnetic radiation that can travel at the speed of light (299.792 km per second) and pass through most substances including wood, tin foil, books and even concrete blocks that ordinary light cannot penetrate. It was discovered in 1895 by German physicist Wilhelm Roentgen.

Roentgen was experimenting with cathode rays, when he noticed that the fluorescent screen had begun to glow although no light was falling on it. He realised that it was due to an invisible ray. He called it X-ray because he did not really know what it was. Later, his colleague named it Roentgen ray.

The discovery of X-rays revolutionised the fields of physics and medicine.

As it can make internal structures of the body visible, X-rays are used to detect bone fractures, dental cavities, tumours, etc.

The flip side of the X-ray is that it can cause biological, chemical and physical changes in substances. It can damage the living tissues of plants and animals if it is absorbed by them. In human beings, an X-ray overdose may produce cancer, skin burns, a reduction of blood supply and other serious conditions.

Today we have a wide range of medical imaging techniques to create visual representations of the internal body. These include CT (computed tomography) scans, MRI (magnetic resonance imaging) and ultrasound.

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How did Wilson Greatbatch invented the pacemaker?

Quite by accident, American engineer Wilson Greatbatch invented the implantable cardiac pacemaker in the year 1958. Read on to know how....

An artificial pacemaker is a small battery-operated electronic device that’s placed under the skin in the chest to help control the heartbeat. The first successful implantable pacemaker was invented in 1958 by an American electrical engineer, Wilson Greatbatch. He was making a heart rhythm recorder when, by mistake, he added a wrong electronic component. He was shocked when the device, instead of simply recording the sound of the heartbeat, produced electronic pulses quite similar to the sounds made by a healthy heart.

It struck him then that the device could make an unhealthy heart beat in rhythm by delivering electrical pulses to make the heart muscles contract and pump blood. For two years he worked on modifying the device. He miniaturised it, coated it with a kind of resin to prevent it from getting damaged by body fluids, and powered it with a mercury-zinc battery.

Greatbatch discussed his invention with surgeon William Chardack, whom he met in a chance encounter. In 1960, the Chardack-Greatbatch pacemaker was implanted in an elderly man with an irregular heartbeat. The patient's life was extended by 18 months.

Pacemakers today are about the size of a bullet. They are encased in titanium and keep the heart ticking with regular beats through computer-guided electrical pulses. They are inserted through the leg up into the right ventricle. Their batteries can last from 5 to 15 years.

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