Radio Astronomy Archives

November 15, 2024November 15, 2024 by Matt Williams

Scientists Develop Technique to Create 3D Models of Cosmic Structures

Milky Way centre by the MeerKAT array of 65 radio dishes in South Africa. Credit: SAROA

For decades, astronomers have used powerful instruments to capture images of the cosmos in various wavelengths. This includes optical images, where visible light is observed, and images that capture non-visible radiation, ranging from the radio and infrared to the X-ray and Gamma-ray wavelengths. However, these two-dimensional images do not allow scientists to infer what the objects look like in three dimensions. Transforming these images into a 3D space could lead to a better understanding of the physics that drives our Universe.

In a recent study, an international team of researchers led by the Minnesota Institute for Astrophysics (MIfA) at the University of Minnesota announced the development of a new technique for radio astronomy. This first-ever technique reconstructs radio images into three-dimensional “Pseudo3D cubes” that allow astronomers to get a better idea of what cosmic structures look like. This technique could lead to an improved understanding of how galaxies, massive black holes, jet structures, and the Universe work.

November 7, 2024November 7, 2024 by Brian Koberlein

You Can Build a Home Radio Telescope to Detect Clouds of Hydrogen in the Milky Way

The 1-meter dish of a home radio telescope. Credit: Jack Phelps

If I ask you to picture a radio telescope, you probably imagine a large dish pointing to the sky, or even an array of dish antennas such as the Very Large Array. What you likely don’t imagine is something that resembles a TV dish in your neighbor’s backyard. With modern electronics, it is relatively easy to build your own radio telescope. To understand out how it can be done, check out a recent paper by Jack Phelps.

September 18, 2024September 18, 2024 by Nancy Atkinson

NASA Watches a Peanut-Shaped Asteroid Drift Past Earth

Near-Earth asteroid 2024 ON. Credit: NASA/JPL.

Peanuts! Get your peanuts here! The Solar System has been passing out peanuts lately in the form of two different oddly shaped asteroids that recently passed by Earth, and both look like over-sized peanuts. The latest peanut-shaped asteroid pass was on September 16, 2024, when the near-Earth asteroid 2024 ON came within 1 million kilometers (62,000 miles) of Earth (2.6 times the Earth-Moon distance). Radar imaging revealed the asteroid was peanut-shaped because it is actually a contact binary – which means it is made of two smaller objects touching each other. NASA says the two rounded lobes are separated by a pronounced neck, and one lobe about 50% larger than the other.

In total, 2024 ON measures about 350 meters (382 yards) long. The radar could resolve features down to about 3.75 meters across on the surface, including brighter boulders. NASA says about 14% of asteroids in this size range (larger than about 200 meters (660 feet)) are contact binaries.

September 8, 2024September 8, 2024 by Matt Williams

ALMA Detects Hallmark “Wiggle” of Gravitational Instability in Planet-Forming Disk

ALMA images reveal vast spiral arms in the AB Aurigae circumstellar disk (three rightmost panels), and counterparts observed with VLT/SPHERE (leftmost panel). Credit: ALMA (ESO/NAOJ/NSF NRAO), VLT/SPHERE (ESO), Speedie et al.

According to Nebula Theory, stars and their systems of planets form when a massive cloud of gas and dust (a nebula) undergoes gravitational collapse at the center, forming a new star. The remaining material from the nebula then forms a disk around the star from which planets, moons, and other bodies will eventually accrete (a protoplanetary disk). This is how Earth and the many bodies that make up the Solar System came together roughly 4.5 billion years ago, eventually settling into their current orbits (after a few migrations and collisions).

However, there is still debate regarding certain details of the planet formation process. On the one hand, there are those who subscribe to the traditional “bottom-up” model, where dust grains gradually collect into larger and larger conglomerations over tens of millions of years. Conversely, you have the “top-down” model, where circumstellar disk material in spiral arms fragments due to gravitational instability. Using the Atacama Large Millimeter/submillimeter Array (ALMA), an international team of astronomers found evidence of the “top-down” model when observing a protoplanetary disk over 500 light-years away.

June 12, 2024June 12, 2024 by Evan Gough

Astronomers Find the Slowest-Spinning Neutron Star Ever

This artist's illustration shows CSIRO’s ASKAP radio telescope with two versions of the puzzling, newly-discovered celestial object: neutron star and white dwarf. Image Credit: Carl Knox, OzGrav

Most neutron stars spin rapidly, completing a rotation in seconds or even a fraction of a second. But astronomers have found one that takes its time, completing a rotation in 54 minutes. What compels this odd object to spin so slowly?

June 4, 2024June 4, 2024 by Nancy Atkinson

Astronomers Have a New Way to Bypass Earth's Atmosphere

Left shows an image of a piece of sky observed with the hitherto best calibration technique. Right shows the same piece of sky with the new technique. More detail is visible, and what were once large, blurry patches now appear as single points. (c) LOFAR/Groeneveld et al.

Radio telescopes have an advantage over optical telescopes, in that radio telescope can be used even in cloudy conditions here on Earth. That’s because the longer wavelengths of radio waves can pass through clouds unhindered. However, some wavelengths are still partially obscured by portions of Earth’s atmosphere, especially by the ionosphere which traps human-made Radio Frequency Interference (RFI).

Astronomers have developed a new calibration technique that allows them to take sharp images in low radio frequencies — between 16 and 30 MHz — for the first time, bypassing the influence of the ionosphere. The astronomers say this will allow them to study things like plasmas emanating from ancient black holes and perhaps even detect exoplanets that orbit small stars.

June 3, 2024June 12, 2024 by Nancy Atkinson

Part 2: The History and Future of Planetary Radar

The Green Bank Observatory in summer. Credit: NSF/GBO/Jill Malusky

To reach the U.S. National Science Foundation’s Green Bank Observatory, you take the road less traveled, winding through scenic and remote regions of the Allegheny Mountains and the Monongahela National Forest of West Virginia. About an hour away, you’ll start to lose cell phone service. The Green Bank Observatory – a collection of radio telescopes that search the heavens for faint radio signals from black holes, pulsars, neutron stars or gravitational waves — sits near the heart of the United States National Radio Quiet Zone, a unique area the encompasses an area of approximately 13,000 square miles, spanning the border between Virginia and West Virginia.

Here in the NRQZ, human-generated radio transmissions are limited to shield the radio telescopes from Earth-based radio signals called RFI (Radio Frequency Interference), which are high-frequency electromagnetic waves that emanate from electronic devices such as computers, cell phones, microwave ovens, and even digital cameras. Even the weakest RFI signals can drown out the faint radio waves coming from the cosmos.

May 30, 2024June 12, 2024 by Nancy Atkinson

Next-Generation Radar Will Map Threatening Asteroids

The Robert C. Byrd Green Bank Telescope. Credit: Jay Young.

When the Arecibo Observatory dish in Puerto Rico collapsed in 2020, astronomers lost a powerful radio telescope and a unique radar instrument to map the surfaces of asteroids and other planetary bodies. Fortunately, a new, next-generation radar system called ngRADAR is under development, to eventually be installed at the the U.S. National Science Foundation’s 100-meter (328 ft.) Green Bank Telescope (GBT) in West Virginia. It will be able to track and map asteroids, with the ability to observe 85% of the celestial sphere. It will also be able to study comets, moons and planets in our Solar System.

“Right now, there is only one facility that can conduct high-power planetary radar, the 70-meter (230-foot) Goldstone antenna that is part of NASA’s Deep Space network,” said Patrick Taylor, the project director for ngRADAR and the radar division head for the National Radio Astronomy Observatory. “We had begun this process of developing a next generation radar system several years ago, but with the loss of Arecibo, this becomes even more important.”

May 15, 2024May 15, 2024 by Evan Gough

A Star Became 1,000 Times Brighter, and Now Astronomers Know Why

Artist’s impression of one of the two stars in the FU Orionis binary system, surrounded by an accreting disk of material. What has caused this star — and others like it — to dramatically brighten? [NASA/JPL-Caltech] — Artist’s impression of one of the two stars in the FU Orionis binary system, surrounded by an accreting disk of material. Credit: NASA/JPL-Caltech

Astronomers were surprised in 1937 when a star in a binary pair suddenly brightened by 1,000 times. The pair is called FU Orionis (FU Ori), and it’s in the constellation Orion. The sudden and extreme variability of one of the stars has resisted a complete explanation, and since then, FU Orionis has become the name for other stars that exhibit similar powerful variability.

March 31, 2024March 31, 2024 by Laurence Tognetti

Radio Astronomy: Why study it? What can it teach us about finding life beyond Earth?

Image of radio telescopes at the Karl G. Jansky Very Large Array, located in Socorro, New Mexico. (Credit: National Radio Astronomy Observatory)

Universe Today has investigated the significance of studying impact craters, planetary surfaces, exoplanets, astrobiology, solar physics, comets, planetary atmospheres, planetary geophysics, cosmochemistry, and meteorites, and how these scientific fields contribute to researchers and the public gain greater insight into our place in the universe and finding life beyond Earth. Here, will discuss the field of radio astronomy with Dr. Wael Farah, who is a research scientist at the SETI Institute, about how radio astronomy teaches us about the myriad of celestial objects that populate our universe, along with the benefits and challenges, finding life beyond Earth, and how upcoming students can pursue studying radio astronomy. But what is radio astronomy and why is it so important to study?