interstellar medium Archives

April 2, 2024April 2, 2024 by Evan Gough

Want to Leave the Solar System? Here’s a Route to Take

A future interstellar probe mission aims to travel beyond the heliosphere to the local interstellar medium to understand where our home came from and where it is going. Credit: John Hopkins Applied Physics Laboratory.

The edge of the Solar System is defined by the heliosphere and its heliopause. The heliopause marks the region where the interstellar medium stops the outgoing solar wind. But only two spacecraft, Voyager 1 and Voyager 2, have ever travelled to the heliopause. As a result, scientists are uncertain about the heliopause’s extent and its other properties.

Some scientists are keen to learn more about this region and are developing a mission concept to explore it.

February 29, 2024February 29, 2024 by Mark Thompson

Astronomers Build a 3D Map of Dust Within Thousands of Light-Years

If you explore the night sky it won’t be long before you realise there is a lot of dust and gas up there. The interstellar dust between the stars accounts for 1% of the mass of the interstellar medium but reflects 30% of the starlight in infrared wavelengths. The dust plays a key role in the formation of stars and the evolution of the Galaxy. A team of astronomers have attempted to map the dust out to a distance of 3000 light years and have just released the first 3D map of the dust in our Galaxy.

April 14, 2023April 14, 2023 by Matt Williams

Twinkling Stars Supply the Dust That Leads to Life

Artist’s impression of the star in its multi-million year long and previously unobservable phase as a large, red supergiant. Credit: CAASTRO / Mats Björklund (Magipics)

When low to medium-mass stars exhaust their supply of hydrogen, they exit their main sequence phase and expand to become red giants – what is known as the Asymptotic Giant Branch (AGB) phase. Stars in this phase of their evolution become variable (experiences changes in brightness) to shed their outer lays, spreading dust throughout the interstellar medium (ISM) that is crucial to the development of planetary nebulas and protoplanetary systems. For decades, astronomers have sought to better understand the role Red Giant stars play.

Studying interstellar and protoplanetary dust is difficult because it is so faint in visible light. Luckily, this dust absorbs light and radiates brightly in the infrared (IR), making it visible to IR telescopes. Using archival data from now-retired Akari and Wide-field Infrared Survey Explorer (WISE) missions, a team of Japanese astronomers conducted the first long-period survey of dusty AGBs and observed that the variable intensity of these stars coincides with the amount of dust they produce. Since this dust plays an important role in the formation of planets, this study could shed light on the origins of life.

January 12, 2023January 12, 2023 by Matt Williams

Astronomers use the World's Biggest Radio Telescope to map new Features of the Milky Way

Artist impression of a fast radio burst. Credit: Danielle Futselaar

Despite everything astronomers have learned about the nature and structure of galaxies, there are still mysteries about the Milky Way. The reason for this is simple: since we are embedded in the Milky Way’s disk, we have difficulty mapping it and observing it as a whole. It’s also very challenging to observe the center of the galaxy, what lies beyond it, and features in the disk itself because of all the gas and dust between stars- the Interstellar Medium (ISM). However, by observing the Milky Way in the non-visible spectrum (radio, x-ray, gamma-ray, etc.), astronomers can see more of what’s out there.

There’s also the spectral line that corresponds to the emission frequency (1420 MHz) of cold neutral hydrogen gas (HI), which makes up the majority of the ISM. Using the Five-hundred-meter Aperture Spherical Telescope (FAST) – the most powerful radio telescope in the world near Guizhou, China – a team of scientists located more than 500 new faint pulsars. During the survey, the team simultaneously recorded the spectral line data with high spectral and spatial resolution, making it an extremely valuable resource for studying the structure of the Milky Way Galaxy and the life cycle of its stars.

February 16, 2022February 16, 2022 by Evan Gough

One of Life’s Building Blocks can Form in Space

A new kind of chemical reaction can explain how peptides can form on the icy layers of cosmic dust grains. Those peptides could have been transported to the early Earth by meteorites, asteroids or comets. Image Credit: © S. Krasnokutski / MPIA Graphics Department

Peptides are one of the smallest biomolecules and are one of life’s critical building blocks. New research shows that they could form on the surfaces of icy grains in space. This discovery lends credence to the idea that meteoroids, asteroids, or comets could have given life on Earth a kick start by crashing into the planet and delivering biological building blocks.

January 14, 2022January 14, 2022 by Evan Gough

Nearby Supernovae Exploded Just a few Million Years Ago, Leading to a Wave of Star Formation Around the Sun

Artist's illustration of the Local Bubble with star formation occurring on the bubble's surface. Scientists have now shown how a chain of events beginning 14 million years ago with a set of powerful supernovae led to the creation of the vast bubble, responsible for the formation of all young stars within 500 light years of the Sun and Earth. Credit: Leah Hustak (STScI)

The Sun isn’t the only star in this galactic neighbourhood. Other stars also call this neighbourhood home. But what’s the neighbourhood’s history? What triggered the birth of all those stars?

A team of astronomers say they’ve pieced the history together and identified the trigger: a series of supernovae explosions that began about 14 million years ago.

April 28, 2021April 28, 2021 by Andy Tomaswick

NASA is now Planning a Mission to go 1,000 AU From the Sun, Deep Into Interstellar Space

A different perspective can do wonders. Perceiving things from a different angle can both metaphorically and literally allow people to see things differently. And in space, there are an almost infinite number of angles that objects can be observed from. Like all perspectives, some are more informative than others. Sometimes those informative perspectives are also the hardest to reach.

Voyager’s two probes did an excellent job in allowing humanity to access some difficult new perspectives simply given their distance from the Earth. But now a team of over 500 scientists and volunteers is urging NASA to go even further to find a better perspective by sending a satellite to a distance 1000 times the distance from the Sun to the Earth – almost 10 times how far the Voyagers have traveled in over 35 years.

January 19, 2021January 19, 2021 by Evan Gough

This is a Simulation of the Interstellar Medium Flowing Like Smoke Throughout the Milky Way

The figure shows a section through the cube of the turbulence simulation. The colors show the density contrast relative to the mean density of the gas. Its turbulent structure is clearly recognizable. Image Credit: Federrath et al, 2021.

How do stars form?

We know they form from massive structures called molecular clouds, which themselves form from the Interstellar Medium (ISM). But how and why do certain types of stars form? Why, in some situations, does a star like our Sun form, versus a red dwarf or a blue giant?

That’s one of the central questions in astronomy. It’s also a very complex one.

June 4, 2020June 4, 2020 by Evan Gough

Astronomers Find the Source of the Huge Bubbles of Gas Flowing Out of the Milky Way, Still No Idea What Caused Them

Astronomers used the WHAM telescope to measure huge outflows of gas extending from the Milky Way’s center known as the Fermi Bubbles. They were able to measure the velocity, density and pressure of the gas for the first time, confirming and extending previous measurements made by using a distant quasar as a light source to look through and measure the gas. IMAGE BY DHANESH KRISHNARAO AND NASA

There’s an unusual paradox hampering research into parts of the Milky Way. Dense gas blocks observations of the galactic core, and it can be difficult to observe in visible light from our vantage point. But distant galaxies don’t always present the same obstacles. So in some ways, we can observe distant galaxies better than we can observe our own.

In order to gain a better understanding of the Galactic Center (GC) and the Interstellar Medium (ISM), a team of astronomers used a telescope called the Wisconsin H-Alpha Mapper (WHAM) to look into the core of the Milky Way in part of the optical light spectrum.

November 6, 2019February 12, 2020 by Evan Gough

What Voyager 2 Learned After Spending a Year in Interstellar Space

An artist concept depicting one of NASA's twin Voyager spacecraft, humanity's farthest and longest-lived spacecraft. Voyager 2 just lost contact with Earth while Voyager 1 is still reporting back. Credit: NASA/JPL-Caltech

Only two of humanity’s spacecraft have left the Solar System: NASA’s Voyager 1 and Voyager 2. Voyager 1 left the heliosphere behind in 2012, while Voyager 2 did the same on Nov. 5th, 2018. Now Voyager 2 has been in interstellar space for one year, and five new papers are presenting the scientific results from that one year.