5 Radio Telescope Discoveries That Are Significant In AstronomySince radio telescopes were developed, significant discoveries have been made. Here we list 5 amazing radio telescope discoveries.
Radio telescopes, like their optical counterparts, are instruments that allow astronomers to observe the universe. However, instead of collecting and reflecting visible light, radio telescopes focus on radio waves and microwaves, which have longer wavelengths than visible light.
What is Radio Astronomy?
The longer wavelengths gathered by radio telescopes provide unique information about the frequency, power, and timing of radio emissions from celestial objects. By collecting and analyzing these radio emissions, astronomers can infer details about space that are not accessible with traditional telescopes, thus expanding our understanding of the universe.
The Arecibo telescope, the largest radio telescope on Earth, has played a pivotal role in numerous astronomical breakthroughs since its establishment in 1960. Developed and operated by Cornell University, radio telescopes have become indispensable tools for observing celestial objects beyond the reach of optical telescopes.
Since their inception, radio telescopes have been instrumental in making numerous groundbreaking discoveries. Here, we present five transformative radio telescope discoveries that have fundamentally reshaped our understanding of the universe.
Asteroid Imaging with Radio Telescopes
In 1989, the Arecibo telescope picked up an asteroid called 4769 Castalia. Asteroids were discovered long before radio telescopes; however, this was the first time scientists had used technology to create a picture of what the asteroid looked like. Using radar imaging, Scott Hudson and Steven Ostro developed a 3-dimensional model of the peanut-shaped Castalia.
Modern telescopes can achieve a much higher resolution, producing more detailed images. Two or more telescopes can also be paired for even greater resolution. Using one telescope to transmit and another to receive can yield significantly more detail than one telescope, and it is a useful method to obtain radar pictures of closely approaching, slowly rotating asteroids.
Binary Pulsar and Millisecond Pulsar Discovery
In 1993, Russell Hulse and Joseph Taylor won the Nobel Prize in Physics for their discovery of pulsars using radio telescopes in 1974. A binary pulsar is a pulsar that has a white dwarf, or neutron star close by that orbits the pulsar to balance the mass and gravitational direction of the pulsar. Millisecond pulsars are neutron stars with an excessively fast rotational duration.
Astronomers are using pulsars all through the Milky Way Galaxy as an enormous scientific instrument to directly discover gravitational waves, which is predicted by Einstein's general theory of relativity.
Exoplanets Discovered with Radio Telescopes
On January 9, 1992, astronomers Alex Wolszczan and Dale Frail came upon exoplanets which are orbiting a pulsar named PSR 1257+12. Like many of the discoveries on this list, it took place at the Arecibo Observatory in Puerto Rico.
Exoplanets are planets that exist outside our Sun's solar system. The discovered exoplanets are about four times as large as our planet, and their proportions closely resemble the spacing between Mercury, Venus, and Earth.
These planets are believed to be orbiting the abovementioned pulsar positioned about 2,300 light-years away within Virgo's constellation. The innermost one circles it every 67 days, while the outer one circles every 98 days. There's also a conceivable third planet, which is further from the pulsar and orbits it about every 360 days.
Mercury's Orbit Discovered with Radio Telescope Observations
In 1964, using the Arecibo telescope, Gordon Pettengill made a significant discovery about the rotation of Mercury. Prior to this, it had been thought that Mercury's orbit takes 88 Earth days. However, Pettengill's observations using the radio telescope led him to theorize that the real rotation of the planet was 59 days. This discovery, which revealed that Mercury rotates three times for every two revolutions around the Sun, significantly altered our understanding of the planet's dynamics and opened new avenues for research.
21 CM Hydrogen Line
The 21 CM Hydrogen Line, discovered and observed by Edward Purcell & Harold Ewen in 1951, is a crucial tool in radio astronomy. This spectral line, emitted by neutral hydrogen, is used to map the distribution of hydrogen within the galaxy. By observing this line, astronomers can determine the relative velocity of each arm of our galaxy, calculate the rotation curve of our galaxy, and even estimate the distance to a certain point inside the galaxy. This discovery has been instrumental in our understanding of the structure and dynamics of the Milky Way.
Assuming that the hydrogen atoms are uniformly distributed all over the galaxy, each line of sight through a galaxy will reveal a hydrogen line. The only distinction between each of these lines is the Doppler shift that each of these lines has. Hence, one can calculate the relative velocity of each arm of our galaxy. The rotation curve of our galaxy has been calculated using the 21 cm hydrogen line. It is then possible to use the plot of the rotation curve and the velocity to determine the distance to a certain point inside the galaxy.
