Explore the Radio Universe from Home

Artist's conception of dwarf star TVLM-513-46546 and its newly-discovered planetary companion.

Explore the fascinating world of radio astronomy with us! Discover the tools scientists use to observe radio waves with a series of apps and features on our website.

Astronomy is one of the oldest sciences in the world, but radio astronomy is the comparatively new kid on the block. The accidental discovery of astronomical radio waves in the 1930s by Karl Jansky, from the center of the Milky Way Galaxy, was overshadowed by the events of World War II, leaving a relative vacuum on radio research. It wasn’t until the 1960s that the field of radio astronomy started to take off, and the technology needed to develop more complicated instrumentation materialized. The burgeoning availability of super-computing power was essential in laying the foundation for discovering some of the extragalactic radio sources today.

Almost everything that is known about the Universe has come to astronomers by way of the electromagnetic spectrum. 

Light in the form of X-rays, infrared and radio behave in different ways. Light has very specific properties — for example, its speed — that do not change no matter its placement on the spectrum of electromagnetic radiation.


Radio waves contain photons with the lowest energies, and come from strange spots in space – the coldest and oldest places, from stars that are made up of the densest material, writes Sarah Scoles in What Radio Waves Tell us of the Universe (a really great introduction to how radio astronomy works). So, at the far end the electromagnetic spectrum, where colder and denser cosmic processes play out, radio wavelengths give us clues about celestial objects that cannot be understood in any other way.

So, take a virtual tour of our radio telescopes and imagine what it would be like to see the Sun, planets, and many other celestial objects in our Solar System in radio light! Create your own multi-wavelength composite image. Build your own telescope array, and observe how the placement of the antennas can affect the way a radio image turns out. Enjoy the amazing world of radio astronomy!

Take a Virtual Telescope Tour with ALMA Observatory and the Very Large Array

ALMA Observatory‘s 66 radio antennas sit high atop the Chajnantor Plateau at 16,500 feet in the Atacama desert in northwestern Chile. It is the driest, non-polar desert on Earth making it an ideal place to do radio astronomy (water vapor in Earth’s atmosphere can distort the reception of radio waves). The Explorer contains over 40 short videos with views ranging from Chilean sights to behind-the-scenes peeks into ALMA construction and operations. Watch the videos in order, or skip around to glimpse the highlights from ALMA’s facility nearly two miles above sea level.


The Very Large Array consists of 27 antennas in a Y-shaped configuration on the Plains of San Agustin fifty miles west of Socorro, New Mexico. Each antenna is 25 meters (82 feet) in diameter and weighs 230 tons. The antennas are moved approximately every four months to one of four different configurations with the help of a specially designed transporter. It is one of the most productive radio telescopes ever

The Very Large Array turns 40 on October 10, 2020, and its scientific contributions are immense. More than 4,500 researchers from around the world have used the VLA for more than 18,000 different observing projects. This iconic telescope was the first to discover ice on Mercury and the first gravitational lens or ‘Einstein Ring.’ Wow!


How to Take the Best Radio Image

How do radio astronomers produce amazing astronomical images from a collection of radio antennas? They use a technique called interferometry. Interferometry works by connecting two or more radio antennas electronically and pointing each antenna toward the same direction in the sky. The number of antennas involved in the observation, and the placement of each, is a factor in determining the quality of the radio image. To get an idea of how this technique works, try out our interactive app.

Follow the Directions on our Interferometry App. to Design the Best Radio Image


Design your own multi-wavelength image for your mobile phone or desktop background with the our Colorful Cosmic Compositor.

Astronomers have produced spectacular, multi-wavelength images such as the Crab Nebula – the remains of a supernova explosion – by combining data from telescopes spanning nearly the entire range of the electromagnetic spectrum, from the long radio waves seen by Very Large Array (VLA) to the shorter x-rays, on the opposite end of the spectrum, observed by NASA’s Chandra X-Ray Observatory. Discover many amazing details of the invisible universe by changing the wavelengths of radio, infrared, ultraviolet, and X-ray to colors your eyes can recognize!


Check out our collection of amazing astronomy posters in a printable 16 X 20 format.

Why Astronomers Want to Use ALMA Observatory’s Radio Telescope

This series of six videos, created by astronomers and workers at ALMA Observatory, focuses on the technology and science behind this powerful radio telescope. Produced for kiddos, adults and non-science majors.