Space News & Blog Articles

Nearly eight years after its historic Pluto flyby, NASA’s New Horizons probe is getting ready for another round of observations made from the icy edge of the solar system — and this time, its field of view will range from Uranus and Neptune to the cosmic background far beyond our galaxy.

Scientists on the New Horizons team shared their latest discoveries, and provided a preview of what’s ahead, during this week’s Lunar and Planetary Science Conference in The Woodlands, Texas.

It’s been 17 years since the piano-sized New Horizons spacecraft was launched toward Pluto and the Kuiper Belt, The primary mission hit its peak in 2015 when the probe zoomed past Pluto, but the adventure moved on to a second act that focused on a smaller, two-lobed object called Arrokoth — a name derived from the Powhatan/Algonquin word for “sky.”

Scientists are still sifting through the data from the Pluto flyby, and from the Arrokoth flyby on New Year’s Day of 2019, more than 4 billion miles from the sun.

Arrokoth’s Origins

Alan Stern, a planetary scientist at the Southwest Research Institute who serves as the mission’s principal investigator, said that close study of Arrokoth’s structure has yielded fresh insights about the early days of the solar system.

According to the most widely-accepted model of cosmology, the Universe began roughly 13.8 billion years ago with the Big Bang. As the Universe cooled, the fundamental laws of physics (the electroweak force, the strong nuclear force, and gravity) and the first hydrogen atoms formed. By 370,000 years after the Big Bang, the Universe was permeated by neutral hydrogen and very few photons (the Cosmic Dark Ages). During the “Epoch of Reionization” that followed, the first stars and galaxies formed, reoinizing the neutral hydrogen and causing the Universe to become transparent.

For astronomers, the Epoch of Reionization still holds many mysteries, like when certain heavy elements formed. This includes the element carbon, a key ingredient in the formation of planets, an important element in organic processes, and the basis for life as we know it. According to a new study by the ARC Center of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), it appears that triply-ionized carbon (C iv) existed far sooner than previously thought. Their findings could have drastic implications for our understanding of cosmic evolution.

ASTRO 3D is a collaborative effort led by Australia National University (ANU), comprising six Australian universities and many international partners. They were joined by researchers from the Astronomical Observatory of Trieste, the Institute for Fundamental Physics of the Universe (IFPU), the Max Planck Institute for Astronomy (MPIA), the MIT Kavli Institute for Astrophysics and Space Research, the Kavli Institute for Cosmology, the Leibniz Institute for Astrophysics Potsdam (AIP), the Gemini Observatory, and the Scuola Normale Superiore. The paper that described their research recently appeared in the Monthly Notices of the Royal Astronomical Society,

A 13.8-billion-year cosmic timeline showing the eras observed by the Planck satellite, HERA, and NASA’s James Webb Space Telescope. Credit: HERA

During the early Universe, young stars fused hydrogen and helium in their interiors to create heavier elements (like metals). As these stars collapsed and went supernova, these elements were dispersed throughout the cosmos and became part of the warm gas and dust clouds surrounding galaxies (aka. galactic halos). When observing the cosmos, astronomers use the C iv in these clouds (“warm carbon”) to trace the metal-rich content of these halos to better understand how galaxies evolved.

There’s something menacing about red dwarfs. Human eyes are accustomed to our benevolent yellow Sun and the warm light it shines on our glorious, life-covered planet. But red dwarfs can seem moody, ill-tempered, and even foreboding.

For long periods of time, they can be calm, but then they can flare violently, flashing a warning to any life that might be gaining a foothold on a nearby planet.

Red dwarfs (M dwarfs) are the most common type of star in the Milky Way. This means that most exoplanets orbit red dwarfs, not nice, well-behaved G-type stars like our Sun. As astronomers study red dwarfs in greater detail, they’ve found that red dwarfs might not be the best stellar hosts when it comes to exoplanet habitability. Multiple studies have shown that red dwarfs can flare violently, emitting enough powerful radiation to render nearby planets uninhabitable, even when they’re firmly in the potentially habitable zone.

But there’s still a lot astronomers don’t know about red dwarfs and their wild nature. A new study examined 177 M-dwarfs to better understand their long-term variability. The researchers found that red dwarf behaviour is more complex than thought, and even the calmest red dwarfs are wilder than the Sun.

The study is titled “Characterisation of stellar activity of M dwarfs. I. Long-timescale variability in a large sample and detection of new cycles.” The paper will be published in the journal Astronomy and Astrophysics. The lead author is Lucile Mignon, a post-doctoral researcher from the University Grenoble Alpes and the French National Centre for Scientific Research (CNRS.)