And now we bring you the second part of our history of the 1900s.
Objects or expanding our knowledge of the Universe, who discovered them:
With all these new discoveries, theories, and fancy technologies we must have found more about the Universe, and we did. One object would be the pulsar, discovered by Jocelyn Bell Burnell and Anthony Hewish. Burnell wasn’t given direct credit until later despite being the actual discoverer. But either way, the discovery came around 1968. It was even thought to be some sort of alien, being called Little Green Men (LGM), but after looking at the radio data, they found what we now call a pulsar, appropriate since they spin so quickly that they appears to pulse in milliseconds. There is also the quasar, discovered by Allan Rex Sandage and Thomas Matthews. Technically it wasn’t discovered by one or two people, but only found after many people spent many years from the 1940’s to 1962 looking at many many spectral and radio sources. Both objects show how radio astronomy allowed us to gain a greater insight into the different objects of our universe.
One of the most famous objects to be detected is the black hole. Technically a black hole can’t be directly seen since it would theoretically appear black as surrounding space, but possible systems and waves of energy created by gravity should be able to detected. The first person to apply modern physics to one of these very dark objects was Karl Schwarzschild, who found that the mass of the progenitor star (the star that the black hole came from) is linked to the distance that a black hole’s gravity would have an effect. The black hole actually has some significant betting and arguing behind it. As stated, Chandrasekhar made a mass limit that was fairly controversial, but with work, people found that a neutron star would have a separate limit which would create a black hole if exceeded. Stephen Hawking bet that the first strong candidate for a black hole, the X-ray binary system Cygnus X-1 which was found by Thomas Bolton, Louise Webster, and Paul Murdin in 1972, would not be one. Hawking is known for making other bets and failing, like betting with John Preskill against Kip Thorne that radiation from a black hole would create an apparent loss of information (he eventually gave up on this), and also betting against the Higgs boson. But the man did discover Hawking radiation and did very important theoretical work despite suffering from an impairing motor neuron disease.
Another very famous discovery was that not only was the Universe expanding like Hubble thought, but it is accelerating as a result of dark energy, something that we don’t exactly understand. This discovery was made in 1998 by Saul Perlmutter, Brian Schmidt, and Adam Riess, using data on Type Ia supernovae collected by Schmidt and Nicholas Suntzeff. The name took a cue from dark matter, as both are placeholders to show their very interesting effects for which we can’t quite find something specific that would create the effect.
There is so much going on with the universe as a whole that we have yet to state the full structure of our very own Solar System. To start we have Planet X, or Pluto (now a dwarf planet). The man who discovered this officially is Percival Lowell, more of an 1800’s man, but he started the lookout for it in 1906, so we figure he belongs here. However, Clyde Tombaugh was the one who really found it, in 1930. Funny how with that we have effectively reached the edge of our Solar System. Well, not really, since Gerard Kuiper discovered the Kuiper belt, a ring of rocky objects around our solar system, and Jan Oort discovered the Oort Cloud, a giant cloud around the Kuiper belt that is almost a sphere of comet-like objects. Oort also created some of the earliest evidence of dark matter and improved radio astronomy. Now, does this mean that we have finally learned everything to know about the Solar System? No, that would be no fun.
Besides all this, two other interesting objects were discovered. One is the brown dwarf; discovered in 1988 by Eric Becklin and Ben Zuckerman. These are “stars”, put in quotes because they haven’t had the mass to start fusion. The other major objects we have discovered are exoplanets, officially discovered also in 1988 by Bruce Campell, G. A. H. Walker, and Stephenson Yang. The reason we mention these two at the same time is because they were thought to be the same thing. Research until 1990 was done to further prove the difference between brown dwarfs and exoplanets, but science always needs further confirmation, so it took until 2003 with some new fancy technology to make it pretty official. But now where does that lead us? You see, there is this situation with Pluto. Finding all these different lower mass objects outside our solar system, we found planets orbiting close to the Sun that are as massive as Jupiter, along with many others. That, it being different from other planets in size and orbit, and the discovery of another dwarf planet named Eris which is more massive and about the size of Pluto created the debate. Poor lonely Pluto, but it’s scientific progress.
There is also the idea of popular science. This was around for a long time, but with the advent of television, movies, and improved speed of print, science could be delivered to a far broader audience. With magazines there were Popular Science and New Scientist. With literature there were the big three, Isaac Asimov, Arthur Clarke, and Robert Heinlein. With television there were Carl Sagan and Bill Nye. All of this was readily available to people, both as inspiration and for learning. A last well-known scientist would be Neil deGrasse Tyson, for supporting NASA and taking after Carl Sagan’s Cosmos to teach many about the grand Universe we live in.
Organizations and general new technologies:
A variety of organizations were formed for space research and to teach the public about Astronomy. One was the American Association of Variable Star Observers (AAVSO) formed in 1911 for amateur and professionals alike to come together and search the skies. There was the International Astronomical Union (IAU) started in 1919. Yes, the people responsible for Pluto’s demotion, but a unified international organization to meet on issues like these is certainly important. Next there is the National Aeronautics and Space Administration (NASA), which was founded in 1958, after the US decided that a Space Race was on with the Soviets. This was some race, even getting men to the moon. But even with that, “NASA spin-off technologies”, such as kevlar, water purification, and LEDs, stemmed from the research. Another organization was Search for Extraterrestrial Intelligence (SETI), set up since 1984. This organization searches everywhere for signs of life, using the Drake Equation, developed by Frank Drake, to show what possibilities to look at when searching for life.
There were many technological advancements like the Mount Wilson Observatory. By the very same man who built the Yerkes Observatory, George Ellery Hale, this was built with the Hooker and Hale telescopes. The importance to this was that from 1917 to 1948 it was the largest reflecting telescope in the world. In addition to that, it was built in mountains near Pasadena, which had improved visibility because of smog trapped over Los Angeles. It was most famously used by Russell for star classification and by Hubble for his major calculations.
But after 1948? Telescopes could be built bigger, created for specific purposes, and the creation of satellites created a completely new view of space. To start, radio astronomy was mainly ground-based, because sending equipment to space is very difficult, costly, time-consuming, and dangerous if repairs are needed. So, if fine radio images can be taken here on Earth, they will be. An example of this is the Very Large Array or VLA, which has detected objects from galaxies to quasars to pulsars. There was also High precision parallax collecting satellite or Hipparcos. Launched from 1989 to 1993 by the European Space Agency, this has taken measurements for the parallax of just about 100,000 stars. The next space telescope launched in 1990 was the famous Hubble Space Telescope. It has shown parts of space unknown to us with the most detail ever seen. It actually had an imperfection with the mirror, which was eventually repaired, but that’s why we like our radio telescopes here on the ground. Speaking of that telescopes on the ground, there are still many that are made for use on Earth. An example would be the Very Large Telescope or VLT. It is indeed large, four reflecting telescopes each with a mirror 8.2 meters in diameter. It was set up in 1999 in the Atacama Desert of Chile since that would allow for far better observations than near a city with pollution (both light and air). To show how useful it was, it was the reason scientists can show stars around the supermassive black hole at the center of the Milky Way and revealing the first exoplanet to be discovered.
Another major space telescope was the Chandra X-ray Observatory, searching the skies as of 1999. This marvel launched by NASA has searched the skies in the X-ray range to show a variety of objects, such as a pulsar in the Crab Nebula. Yet another major space telescope was the Spitzer Space Telescope, launched by NASA in 2003. It has imaged a variety of objects in the infrared range. The next space observatory to be launched was Kepler. As we said, Kepler had a satellite named after him for being awesome, and his namesake has been searching the skies for exoplanets since 2009, finding over 2,000 candidates, with about 200 being similar to Earth. Another notable space telescope which hasn’t been launched yet is the James Webb Space Telescope, being launched by NASA in 2018 as Hubble’s successor. For comparison, Hubble had a 2.4 meter mirror and Spitzer an 85 cm mirror, while the James Webb will have an 8 mirror meter optimized for infrared observations, so it should be able to show a whole new perspective of space.
TL;DR — This was quite a bit of history to discuss. But it is Astronomy, so there is certainly more. This was to give an overview of the vocabulary, people, and Astronomy in general. Now we can explore even deeper into the Universe and how it works. But what is expected in Astronomy and what are the problems after looking at all these people? It is:
1. Astronomy is really awesome, it can relate to anyone’s imagination. It is so abstract and great to write, talk, or think about since it is discusses the skies and stars, we can’t reach it yet, but it shows how most subjects can be tied together. It can even be useful with a variety of satellite or material technologies developed.
2. Astronomers do the work, it’s not often that a eureka moment occurs as much as data, predictions, and models are created to show a probable event either before or after collecting data for it. It may not sound as exciting, but it actually is more amazing to be able to do that if you think about it.
3. Dark matter, dark energy, quasars, black holes, and many objects even within our own solar system still are not completely understood.
4. Lots Of Acronyms. Or LOA.
For more on this go to: http://heasarc.gsfc.nasa.gov/docs/heasarc/headates/1900.html