If Gravity Can Exist Without Mass, That Could Explain Dark Matter

Researchers are making progress mapping dark matter, but they don't know what it is. This is a 3D density map of dark matter in the local universe, with the Milky Way marked by an X. Dots are galaxies, and the arrows indicate the directions of motion derived from the reconstructed gravitational potential of dark matter. Image Credit: Hong et al., doi: 10.3847/1538-4357/abf040.

Dark Matter is Nature’s poltergeist. We can see its effects, but we can’t see it, and we don’t know what it is. It’s as if Nature is playing tricks on us, hiding most of its mass and confounding our efforts to determine what it is.

Continue reading “If Gravity Can Exist Without Mass, That Could Explain Dark Matter”

The Milky Way’s Last Merger Event Was More Recent Than Thought

Our home galaxy as seen by the European Space Agency’s Gaia satellite. Image Credit: ESA/Gaia/DPAC

The Milky Way is only as massive as it is because of collisions and mergers with other galaxies. This is a messy process, and we see the same thing happening with other galaxies throughout the Universe. Currently, we see the Milky Way nibbling at its two satellite galaxies, the Large and Small Magellanic Clouds. Their fate is likely sealed, and they’ll be absorbed into our galaxy.

Researchers thought the last major merger occurred in the Milky Way’s distant past, between 8 and 11 billion years ago. But new research amplifies the idea that it was much more recent: less than 3 billion years ago.

Continue reading “The Milky Way’s Last Merger Event Was More Recent Than Thought”

An Earth-sized Exoplanet Found Orbiting a Jupiter-Sized Star

This artist's illustration shows the exoplanet SPECULOOS-3 b orbiting its red dwarf star. The planet is as big around as Earth, while its star is slightly bigger than Jupiter – but much more massive. The planet is a prime candidate for follow-up studies with the JWST. Credit: NASA/JPL-Caltech

Red dwarf stars, also known as M-dwarfs, dominate the Milky Way’s stellar population. They can last for 100 billion years or longer. Since these long-lived stars make up the bulk of the stars in our galaxy, it stands to reason that they host the most planets.

Astronomers examined one red dwarf star named SPECULOOS-3, a Jupiter-sized star about 55 light-years away, and found an Earth-sized exoplanet orbiting it. It’s an excellent candidate for further study with the James Webb Space Telescope.

Continue reading “An Earth-sized Exoplanet Found Orbiting a Jupiter-Sized Star”

Primordial Black Holes Can Only Explain a Fraction of Dark Matter

This artist's illustration shows what primordial black holes might look like. In reality, the black holes would struggle to form accretion disks, as shown. Image Credit: NASA’s Goddard Space Flight Center

What is Dark Matter? That question is prominent in discussions about the nature of the Universe. There are many proposed explanations for dark matter, both within the Standard Model and outside of it.

One proposed component of dark matter is primordial black holes, created in the early Universe without a collapsing star as a progenitor.

Continue reading “Primordial Black Holes Can Only Explain a Fraction of Dark Matter”

The JWST is Re-Writing Astronomy Textbooks

The first JWST Deep Field Image, showing large distant galaxies. The telescope's observations are revealing the previously unseen and are forcing a re-write of astronomy textbooks. Image Credit: NASA, ESA, CSA, STScI

When the James Webb Space Telescope was launched at the end of 2021, we expected stunning images and illuminating scientific results. So far, the powerful space telescope has lived up to our expectations. The JWST has shown us things about the early Universe we never anticipated.

Some of those results are forcing a rewrite of astronomy textbooks.

Continue reading “The JWST is Re-Writing Astronomy Textbooks”

How Mars’ Moon Phobos Captures Our Imaginations

This is a colourized version of a black and white image captured by the ESA's Mars Express in 2010. Andrea Luck, a skilled image processor from Glasgow, improved the original image. Image Credit: ESA/DLR/FUBerlin/AndreaLuck CC BY. Original Image: https://www.planetary.org/space-images/20130714_phobosnd_img

For a small, lumpy chunk of rock that barely reflects any light, Mars’ Moon Phobos draws a lot of attention. Maybe because it’s one of only two moons to orbit the planet, and its origins are unclear. But some of the attention is probably because we have such great images of it.

Continue reading “How Mars’ Moon Phobos Captures Our Imaginations”

Evidence of Dark Matter Interacting With Itself in El Gordo Merger

Image from a computer simulation of the distribution of matter in the universe. Orange regions host galaxies; blue structures are gas and dark matter. Credit: TNG Collaboration

The Standard Model of particle physics does a good job of explaining the interactions between matter’s basic building blocks. But it’s not perfect. It struggles to explain dark matter. Dark matter makes up most of the matter in the Universe, yet we don’t know what it is.

The Standard Model says that whatever dark matter is, it can’t interact with itself. New research may have turned that on its head.

Continue reading “Evidence of Dark Matter Interacting With Itself in El Gordo Merger”

Life Probably Played No Role in Mars’ Organic Matter

Color mosaic image of Mars, taken by the HRSC instrument aboard the ESA's Mars Express orbiter. Credit: ESA/DLR/FU Berlin (G. Michael)

The Martian surface shows ample evidence of its warm, watery past. Deltas, ancient lakebeds, and dry river channels are plentiful. When the Curiosity rover found organic matter in ancient sediments in the Jezero Crater paleolake, it was tempting to conclude that life created the matter.

However, new research suggests that non-living processes are responsible.

Continue reading “Life Probably Played No Role in Mars’ Organic Matter”

What’s Under This Hole on the Surface of Mars?

The HiRISE camera on NASA's Mars Reconnaissance Orbiter captured this image to determine if any underlying voids or associated faults can be observed in this part of Arsia Mons. Pits like this can be caused by recent geologically-recent volcanic or tectonic activity. If there are caves under the pit, they could one day act as shelter for astronauts. The caves could also be targets for future robotic exploration. The pit is only a few meters across. Image Credit: NASA/JPL-Caltech/UArizona

Human visitors to Mars need somewhere to shelter from the radiation, temperature swings, and dust storms that plague the planet. If the planet is anything like Earth or the Moon, it may have large underground lava tubes that could house shelters. Collapsed sections of lava tubes, called skylights, could provide access to these subterranean refuges.

Does this hole on Mars lead to a larger underground cavern?

Continue reading “What’s Under This Hole on the Surface of Mars?”

Sorry Spock, But “Vulcan” Isn’t a Planet After All

This artist's illustration shows the exoplanet Eridani b, aka Vulcan, home of Star Trek's Commander Spock. Unfortunately, evidence is mounting that the planet isn't really there. Image Credit: JPL-Caltech

In 2018, astronomers detected an exoplanet around the star 40 Eridani. It’s about 16 light-years away in the constellation Eridanus. The discovery generated a wave of interest for a couple of reasons. Not only is it the closest Super-Earth around a star similar to our Sun, but the star system is the fictional home of Star Trek’s Vulcan science officer, Mr. Spock.

It’s always fun when a real science discovery lines up with science fiction.

Continue reading “Sorry Spock, But “Vulcan” Isn’t a Planet After All”