“My parents gave me a small telescope, then I built my own, and one thing led to another. So that’s how I ended up going from being a hobby astronomer to a professional astronomer.” – Dimitar Sasselov, Bulgarian astronomer based in the United States. He is a Professor of Astronomy at Harvard University and director of the Harvard Origins of Life Initiative.
In the beginning, people’s knowledge about the stars was limited by the power of their own eyes. The inventions of lenses, mirrors, and eventually the telescope made it possible to see more things clearly. The history of astronomy is tied to the development of the telescope, since we need to observe things in order to understand them.
In 1608 Hans Lippershey (or Lipperhey), a Dutch eyeglass maker, was the first man to apply for a patent for the telescope. Others also claimed to be the inventor, but the Dutch government accepted his patent as the first.
While the earliest telescopes only magnified things a few times, Galileo Galilei worked hard and was able to eventually make his telescope magnify things till they were 10 times larger. By 1610, Galileo had a telescope that magnified 30 times. He was able to see craters on the moon and even the moons orbiting the planet Jupiter.
A 1754 painting by H.J. Detouche shows Galileo Galilei displaying his telescope to Leonardo Donato and the Venetian Senate.
Johannes Kepler also improved upon the early refracting telescopes. Instead of a concave and a convex lens, he tried two convex lenses. (Concave lenses curve inward, like a bowl, while convex lenses curve out.) The largest refracting telescope ever built had a lens 40 inches wide. It opened in 1897 at Yerkes Observatory in Williams Bay, Wisconsin.
Sir Isaac Newton studied Kepler’s work and decided it might be a better idea to build a telescope using mirrors instead of lenses. Mirrors reflect light, while lenses allow light to pass through them and bend (refract) the light. In 1668 he built the first practical reflecting telescope. For many years scientists used both refracting and reflecting telescopes, but the reflector became the favorite of astronomers.
Diagram of Isaac Newton’s reflecting telescope, 1672. Image courtesy of the Royal Society of London.
In the 1920’s most STEMists believed the universe was static (unchanging) in size. But then came along astronomer Edwin Hubble in 1929 who published his findings that the universe is expanding! He did not directly see the universe expand like a balloon but calculated the velocity of light spectra from far away galaxies. (Light from a galaxy has specific characteristics, spectrum, based on the make-up or composition of the galaxy.) From these calculations, Edwin Hubble determined that nearly all galaxies are moving away from us, and the farther the galaxies are from us, the faster they are moving … the universe is expanding!
Karl Guthe Jansky detected radio waves in outer space in 1931. This discovery inspired engineers to develop radio telescopes and other types of telescopes for measuring and mapping microwaves, gamma rays, and other electromagnetic radiation. These telescopes helped scientists “see” invisible radiation and use it to detect objects such as pulsars.
Hubble Space Telescope Is The GROOVIEST!
The Hubble Space Telescope was launched on April 24, 1990 with the Space Shuttle Discovery. Since then, it has been in a low orbit around the earth. The Hubble Space Telescope is a reflecting telescope that also has digital cameras and satellite communications so it can send us groovy images. These images are clearer than earthbound astronomers can see because the Hubble is outside earth’s atmosphere and gets a clearer view of distant objects. The Hubble is the only telescope designed to be adjusted and repaired in space by astronauts.
Hubble Space Telescope in a low orbit around the earth.
Groovy Images From The Hubble Space Telescope!
A replacement for the Hubble Space Telescope, the James Webb Space Telescope, is planned for launch in 2018. There are always ways to improve the telescope, so we never stop adding to our knowledge of the stars.
If your STEMist loves telescopes and star stuff, be sure to check out our “Moon Dance” groovy box – explore Earth’s moon, gravity, mass vs. weight, moon phases, tides, light, telescopes and much, much, more. Join Now! and challenge your STEMists to a monthly Groovy Lab in a Box, full of everything a child needs to learn about and do hands-on science, technology, engineering, and mathematics (STEM) investigations and engineering design challenges. Our monthly box activates thinking, questioning, inquiring and original creation as we guide children through scientific inquiry and the engineering design process.
A groovy thank you to Oh, Star Stuff for providing some of the groovy Hubble Space Telescope images above.
Young STEMists can learn much from the life of Galileo. Like all good STEMists, he studied the work of those who had gone before him. As he studied, he asked questions to test those ideas. Sometimes he found new, better explanations for the way things work. Every good STEMist learns from the past and tries to go further and do better.
Galileo Galilei was born in 1564 in Pisa, Italy. His father was a musician. Though the family was noble, they were not wealthy. In 1581, Galileo was sent to the University of Pisa to study medicine. While there, he was especially fascinated by the fields of mathematics and physics.
Galileo became a professor at the University of Pisa, where he taught from 1589 through 1592. He did research on the motion of falling objects. At that time, STEMists still believed the world operated the way Aristotle, a famous Greek philosopher, had described. They believed, for example, that the earth was the center of the universe and that heavier objects fell faster than lightweight objects. Galileo’s research, which he published in a book, On Motion, showed that all objects fall at the same rate in a vacuum. This was not what Aristotle had predicted.
After his time at the University of Pisa, Galileo taught geometry, mechanics, and astronomy at the University of Padua for eighteen years. During this time he began to support the theory of Nicolaus Copernicus, a Polish astronomer who said the planets revolved around the sun.
We call this the heliocentric (sun-centered) view as opposed to Aristotle’s geocentric (earth-centered) view. Galileo made improvements to a Dutch telescope and was the first to use the telescope to make observations in astronomy. He saw that the moon, which people had thought was smooth, was actually covered in craters. He also observed that Jupiter had moons of its own–and those moons did not revolve around the earth.
He studied the motion of pendulums and came up with the idea of a pendulum clock. He also invented a water pump and made improvements to the refracting telescope, though he did not invent the telescope itself. Like many learned men of his day, Galileo was interested in many things and let his curiosity spur him to study problems until he came up with solutions.
Unfortunately, Galileo’s solutions were not popular with some powerful people in Italy. Pope Urban VIII did not approve of his Copernican ideas. The Catholic Church at that time had decided Aristotle’s ideas were correct. The Pope had Galileo found guilty of heresy (going against church teachings) and the STEMist spent the rest of his life under house arrest. In 1758 the Catholic Church at last lifted the ban on Copernicus’ heliocentric theory. The evidence by that time was clear–Galileo had been right all along to reject Aristotle’s view. In 1992 Pope John Paul II expressed regret at the way Galileo had been treated by the church.
Galileo’s life shows how ideas in STEM can change. Long ago, people came up with ideas (theories) that seemed to explain the motion of objects. Later, when people had equipment to take better measurements or to see more clearly, they found problems with the old theories and devised new ones that better explained what they observed. Remember we have never reached a point where we have learned everything for sure!
Maybe you will take the next big STEM leap!