Updated: Jun 7
This article was written by site member Jason Cook. This is the first Galactic Hunter post written by an outside contributor.
A radio telescope is completely different from an optical telescope that we are more familiar with. The difference between the two is that an optical telescope basically reflects or mirrors an image, while a radio telescope is reliant on radio wavelengths to produce a not so exact image of what is observed.
If you take a look at what both telescopes can see, optical telescopes basically zoom towards a faraway object. A radio telescope image looks pretty similar to the images produced by a thermal camera. You can always check out telescope reviews for you to have a better idea of what really separates the two.
It’s very easy to distinguish the two since radio telescopes are really big and noticeable because of the dish and antenna that it has. The largest radio telescope in the world for the longest time was the one found in Arecibo, Puerto Rico. It covers a 20-acre field. Imagine that!
What might surprise you is that there’s a new radio telescope in China that has already beaten Arecibo’s radio telescope. In 2016, China has already finished building the Five-hundred-meter Aperture Spherical Telescope (FAST). The one in Arecibo is only about 1000 feet across, but FAST covers 1,600 feet.
Now, radio telescopes actually play a big role when it comes to learning more about what’s outside our planet. In fact, since it was invented, there were significant discoveries that helped astronomers understand celestial bodies better.
Here are five interesting discoveries with the use of a radio telescope.
1. The discovery of Ubiquitous Radiation Throughout the Universe that Supports the Big Bang Theory
While ubiquitous sounds like a tough word, it simply means that the radiation that was detected by a radio telescope is present or found everywhere throughout the universe. This was discovered in 1941 by a Canadian astronomer named Andrew Mckellar.
The Big Bang is one of the most interesting theories when it comes to how the universe came about. A common misconception about this theory is that there was an explosion that’s why the universe we are in came into form.
Apparently, experts say that there was no explosion that happened. What really happened was an expansion that is still said to be continuing up to now.
The radiation detected by McKellar was initially not interpreted until two decades later when two astronomers were surprised with how intense the noise this radiation produced. Later on, with a few more astronomers, they concluded that this radiation is the signature of the Big Bang.
2. The 21cm Hydrogen Line
It was in the year 1951 when this line was first observed by astronomers from Harvard using radio telescopes. This helped shape the first maps of hydrogen in the galaxy and spiral structures like the Milky Way.
This 21cm hydrogen line is what was also used for the rotation curve of the galaxy. It also helps the astronomers study the dynamics of different galaxies. Interestingly, in 1951, there were physicists involved with SETI that proposed the significance of this hydrogen line with their search for non-human intelligent life.
Discovered in the 1960s, Quasars are considered as one of the brightest and energized objects in the universe. A quasar is found in the center of a galaxy. This is where black holes are said to be in place. Given that it’s pretty much the brightest object in different galaxies, a quasar’s temperature is estimated to be 18 trillion degrees Fahrenheit.
Quasars are said to be stationary for our technology as of now because they’re too far away.
Currently, astronomers use a quasar as a reference point for creating measurement grids on the sky. Aside from that, a quasar also helps astronomers understand different galaxies. What remains interesting about this is the source of its energy since this is still something that’s hard to discover.
In 1967, the first pulsar was observed. The name is a combination of two words – pulsing and quasar, but it really means pulsating star. Pulsars are actually neutron stars that give radio emissions. They are close to being a black hole but they only emit narrow beams similar to a lighthouse.
Astronomers said that pulsar signals are similar to the ticking of clocks but some astronomers and physicist would say that creating a pulsar-based time standard would be something hard to achieve. As of now, this is still a work in progress.
One great use of studying pulsars is the discovery of exoplanets. Aside from that, in the 1980s, pulsar radiation was used to prove the movement of continents. The precise observation that proved this with the use of pulsars would be how the continents of North America and Europe are drifting away from each other.
5. Star Formation
Radio telescopes helped astronomers figure out how stars are formed and even break or die. Whenever stars are formed, radio waves easily pass through the Earth’s atmosphere because of their intensity. This is when astronomers get really invested when it comes to how stars are born.
Now when stars die, supernova explosions happen. This also results in images that can be seen by an optical telescope, but a supernova explosion can be wide and even invisible at some part. That’s when radio telescopes are needed to see the extent of such explosions.
As mentioned earlier, China already has the largest radio telescope in the world. One of its purposes is to discover interstellar communication. This means that it is possible that this telescope can detect communication from non-humans.
Aside from that bold purpose, radio telescope also aims to discover more than what it already has discovered.
Now that the evolution of our technology is considered non-stop, you should only hope that newer versions of radio telescopes improve how we know not only the galaxy we are in but also others that are yet undiscovered.
Thank you to Jason Cook for this really interesting post! You can visit his website here.