Astronomy Archives

January 12, 2025January 12, 2025 by Matt Williams

Planets Can Form in Even the Harshest Conditions

Artist concept of planet formation occuring in harsh stellar environments. Credit: NSF/AUI/NSF NRAO/S.Dagnello.

According to the most widely held astronomical model (the Nebular Hypothesis), new stars are born from massive clouds of dust and gas (aka. a nebula) that experience gravitational collapse. The remaining dust and gas form a protoplanetary disk that encircles the new star, which slowly accretes to form systems of planets. For the past decade, astronomers have relied on the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile to study young stars and their disks and learn more about how this process occurs.

In a recent study, an international team of astronomers used ALMA to capture high-resolution images of eight protoplanetary disks in the Sigma Orionis cluster, a group of stars located in the constellation Orion. During their observations, the team found evidence of gaps and rings in most of the disks, which are potential indications that giant planets are forming. This was surprising, seeing as how these disks are irradiated by intense ultraviolet (UV) radiation from a massive star in the cluster. Their findings suggest that planet formation can occur in conditions that were previously thought to be inhospitable.

January 11, 2025January 11, 2025 by Paul M. Sutter

Is There a Fifth Force of Nature?

During particle collisions, hadrons split into quarks and bosons (University of Oregon)

Could a new, fifth force of nature provide some answers to our biggest questions about dark matter and dark energy? We’re working on it.

January 9, 2025January 9, 2025 by David Dickinson

The Moon Occults Mars for North America Monday Night, Just Before Opposition 2025

Now is the best time to observe Mars in 2025.

January has an amazing parade of evening planets, well worth braving the cold for. We have brilliant Venus, high to the west after sunset, reaching greatest elongation on January 10^th. Fainter Saturn sits just above Venus as the two meet on January 19^th. Meanwhile, Jupiter dominates the eastern sky, fresh off of opposition in December. But stay awake just a bit longer after dusk, and you can see Mars rising in the east.

As a special treat, observers in most of North America will also see the nearly Full Moon pass in front of Mars Monday night.

January 8, 2025January 8, 2025 by Brian Koberlein

Astronomers are Losing the Night Sky (and Radio Sky) to Satellite Megaconstellations

How constellation satellites can create light pollution for radio telescopes. Credit: IAU CPS/NOIRLab/SKAO

When was the last time you looked up into the night sky and saw the Milky Way? If you happen to live in one of the truly remote areas of the world, your answer might be “last night.” If you live in one of the generally “rural” areas of your country, you might remember how you used to see the Milky Way regularly, but the rise of LEDs, particularly the blue/white ones, has gradually erased the Milky Way from your nights. For the large majority of humans on our small world, the answer is “never.”

January 7, 2025January 7, 2025 by Carolyn Collins Petersen

The Lunar Surface Remelted, Obscuring an Easy Answer to its True Age

A few hundred million years after its formation, the Moon was subject to intense volcanic activity. The distance between the Earth and the Moon was much smaller back then than it is today. Lunar surface rocks reflect a younger age due to a "melting" event at the time. MPS / Alexey Chizhik, CC BY-NC-ND

How old is the Moon? Astronaut-gathered samples from the lunar surface put its age at about 4.35 billion years. However, other evidence suggests it’s much older, around 4.53 billion years old. A team of scientists published a recent paper that suggests the Moon’s surface age was “reset” in a melting event.

January 6, 2025January 6, 2025 by Evan Gough

An Early Supermassive Black Hole Took a Little Break Between Feasts

This artist’s impression shows a black hole about 800 million years after the Big Bang, during one of its short periods of rapid growth. Image Credit: Jiarong Gu

In the last couple of decades, it’s become increasingly clear that massive galaxies like our own Milky Way host supermassive black holes (SMBHs) in their centres. How they became so massive and how they affect their surroundings are active questions in astronomy. Astronomers working with the James Webb Space Telescope have discovered an SMBH in the early Universe that is accreting mass at a very low rate, even though the black hole is extremely massive compared to its host galaxy.

What’s going on with this SMBH, and what does it tell astronomers about the growth of these gargantuan black holes?

January 6, 2025January 6, 2025 by David Dickinson

Will Comet G3 ATLAS Perform at Perihelion?

Comet C/2024 G3 ATLAS may put on a quick show this month.

What ‘may’ be the best anticipated comet of 2025 is coming right up. Right now, there’s only one comet with real potential to reach naked eye visibility in 2025: Comet C/2024 G3 ATLAS. This comet reaches perihelion at 0.094 Astronomical Units (AU, 8.7 million miles or 14 million kilometers, interior to the orbit of Mercury) from the Sun on January 13^th, and ‘may’ top -1^st magnitude or brighter. At magnitude +4 in late December, Comet G3 ATLAS could become a fine object low in the dawn sky for southern hemisphere observers… if (a big ‘if) it holds together and performs as expected.

January 2, 2025January 2, 2025 by Matt Williams

NASA Scientists Discover “Dark Comets” Come in Two Populations.

An artist's concept of a dark comet floating in space. Courtesy Nicole Smith.

On October 19th, 2017, the Panoramic Survey Telescope and Rapid Response System-1 (Pan-STARRS-1) in Hawaii announced the first-ever detection of an interstellar object, named 1I/2017 U1 ‘Oumuamua (the Hawaiin word for “scout”). This object created no shortage of confusion since it appeared as an asteroid but behaved like a comet (based on the way it accelerated out of the Solar System). Since then, scientists have noticed a lot of other objects that behave the same way, known as “dark comets.”

These objects are defined as “small bodies with no detected coma that have significant nongravitational accelerations explainable by outgassing of volatiles,” much like ‘Oumuamua. In a recent NASA-supported study, a team of researchers identified seven more of these objects in the Solar System, doubling the number of known dark comets. Even more important, the researchers were able to discern two distinct populations. They consist of larger objects that reside in the outer Solar System and smaller ones in the inner Solar System.

January 1, 2025January 1, 2025 by Scott Alan Johnston

New Glenn Completes a Hotfire Test. Next… Flight?

New Glenn during successful integrated vehicle hotfire on December 27. (Credit: Blue Origin)

Blue Origin has achieved an important milestone with its New Glenn NG-1 rocket, successfully completing a 24-second hotfire of the rocket’s BE-4 engines in preparation for an expected test flight in the coming days.

December 31, 2024December 31, 2024 by Matt Williams

A Young Exoplanet's Atmosphere Doesn't Match its Birthplace

The natal disk of PDS 70 with new planet PDS 70b (bright spot on the right). Credit: ESO/A. Müller et al.

If the modern age of astronomy could be summarized in a few words, it would probably be “the age of shifting paradigms.” Thanks to next-generation telescopes, instruments, and machine learning, astronomers are conducting deeper investigations into cosmological mysteries, making discoveries, and shattering preconceived notions. This includes how systems of planets form around new stars, which scientists have traditionally explained using the Nebular Hypothesis. This theory states that star systems form from clouds of gas and dust (nebulae) that experience gravitational collapse, creating a new star.

The remaining gas and dust then settle into a protoplanetary disk around the new star, which gradually coalesces to create planets. Naturally, astronomers theorize that the composition of the planets would match that of the disk itself. However, when examining a still-developing exoplanet in a distant star system, a team of astronomers uncovered a mismatch between the gases in the planet’s atmosphere and those within the disk. These findings indicate that the relationship between a protoplanetary disk and the planets they form might be more complicated.