Universe Today

May 15, 2024May 15, 2024 by Mark Thompson

Three of the Oldest Stars in the Universe Found Circling the Milky Way

MIT astronomers discovered three of the oldest stars in the universe, and they live in our own galactic neighborhood. The stars are in the Milky Way’s “halo” — the cloud of stars that envelopes the main galactic disk — and they appear to have formed between 12 and 13 billion years ago, when the very first galaxies were taking shape. Credits:Image: Serge Brunier; NASA

Mention the Milky Way and most people will visualise a great big spiral galaxy billions of years old. It’s thought to be a galaxy that took shape billions of years after the Big Bang. Studies by astronomers have revealed that there are the echo’s of an earlier time around us. A team of astronomers from MIT have found three ancient stars orbiting the Milky Way’s halo. The team think these stars formed when the Universe was around a billion years old and that they were once part of a smaller galaxy that was consumed by the Milky Way.

May 15, 2024May 15, 2024 by Mark Thompson

A Rotating Spacecraft Would Solve So Many Problems in Spaceflight

DALL-E image of a rotating space station

If you watch astronauts in space then you will know how they seem to float around their spaceship. Spaceships in orbit around the Earth are in free-fall, constantly falling toward surface fo the Earth with the surface constantly falling away from it. Any occupant is also in free-fall but living like this causes muscle tone to degrade slowly. One solution is to generate artificial gravity through acceleration in particular a rotating motion. A new paper makes the case for a rotating space station and goes so far that it is achievable now.

May 14, 2024May 14, 2024 by Matt Williams

White Dwarfs are Often Polluted With Heavier Elements. Now We Know Why

In this artist's illustration, lumps of debris from a disrupted planetesimal are irregularly spaced on a long and eccentric orbit around a white dwarf. Credit: Dr Mark Garlick/The University of Warwick

When stars exhaust their hydrogen fuel at the end of their main sequence phase, they undergo core collapse and shed their outer layers in a supernova. Whereas particularly massive stars will collapse and become black holes, stars comparable to our Sun become stellar remnants known as “white dwarfs.” These “dead stars” are extremely compact and dense, having mass comparable to a star but concentrated in a volume about the size of a planet. Despite being prevalent in our galaxy, the chemical makeup of these stellar remnants has puzzled astronomers for years.

For instance, white dwarfs consume nearby objects like comets and planetesimals, causing them to become “polluted” by trace metals and other elements. While this process is not yet well understood, it could be the key to unraveling the metal content and composition (aka. metallicity) of white dwarf stars, potentially leading to discoveries about their dynamics. In a recent paper, a team from the University of Colorado Boulder theorized that the reason white dwarf stars consume neighboring planetesimals could have to do with their formation.

May 14, 2024May 14, 2024 by Mark Thompson

Saturn-Sized Exoplanet Isn’t Losing Mass Quickly Enough

Pablo Carlos Budassi - Own work. Simulated view of a mini-Neptune or "gas dwarf"

We have discovered over 5,000 planets around other star systems. Amongst the veritable cosmic menagerie of exoplanets, it seems there is a real shortage of Neptune-sized planets close to their star. A new paper just published discusses a Saturn-sized planet close to its host star which should be experiencing mass loss, but isn’t. Studying this world offers a new insight into exoplanet formation across the Universe.

May 14, 2024May 14, 2024 by Andy Tomaswick

Gravitational Lenses Could Pin Down Black Hole Mergers with Unprecedented Accuracy

Gravitational wave astronomy has been one of the hottest new types of astronomy ever since the LIGO consortium officially detected the first gravitational wave (GW) back in 2016. Astronomers were excited about the number of new questions that could be answered using this sensing technique that had never been considered before. But a lot of the nuance of the GWs that LIGO and other detectors have found in the 90 gravitational wave candidates they have found since 2016 is lost.

Researchers have a hard time determining which galaxy a gravitational wave comes from. But now, a new paper from researchers in the Netherlands has a strategy and developed some simulations that could help narrow down the search for the birthplace of GWs. To do so, they use another darling of astronomers everywhere—gravitational lensing.

May 14, 2024May 14, 2024 by Evan Gough

TRAPPIST-1 Outer Planets Likely Have Water

Three of the TRAPPIST-1 planets – TRAPPIST-1e, f and g – dwell in their star’s so-called “habitable zone. CreditL NASA/JPL

The TRAPPIST-1 solar system generated a swell of interest when it was observed several years ago. In 2016, astronomers using the Transiting Planets and Planetesimals Small Telescope (TRAPPIST) at La Silla Observatory in Chile detected two rocky planets orbiting the red dwarf star, which took the name TRAPPIST-1. Then, in 2017, a deeper analysis found another five rocky planets.

It was a remarkable discovery, especially because up to four of them could be the right distance from the star to have liquid water.

May 13, 2024May 13, 2024 by Mark Thompson

Perseverance Wraps Up Over 1,000 Days on Mars. Still Going Strong

Perseverance rover on Mars. Image credit: NASA

I can remember when Perseverance was launched, travelled out into the Solar System and landed on Mars in February 2021. In all the time since it arrived, having clocked up 1000 days of exploration, it has collected 23 samples from different geological areas within the Jezero Crater. The area was once home to an ancient lake and if there is anywhere on Mars to find evidence of ancient (fossilised) life, it is here.

May 13, 2024May 13, 2024 by Mark Thompson

Astronomers Try to Directly Observe Epsilon Eridani b. No Luck. Maybe Webb Can Find it?

Back in the year 2000, Epsilon Eridani b was discovered. It is a Jupiter-like exoplanet 10.5 light years away but it has taken decades of observations to learn more about the planet. One thing that remains a mystery is it’s orbit which, until recently has been unknown. There has never been a direct image of the planet either, so now, it’s the turn of JWST to see what it can do.

May 13, 2024May 13, 2024 by Andy Tomaswick

Some Clever Ways to Search for Primordial Black Holes

Primordial Black Holes (PBHs) have recently received much attention in the physics community. One of the primary reasons is the potential link to dark matter. In effect, if PBHs can be proven to exist, there’s a very good chance that they are what dark matter, the invisible thing that makes up 85% of the universe’s mass, is made of. If proven, that would surely be a Nobel-level discovery in astrophysics.

May 13, 2024May 14, 2024 by Mark Thompson

These Rocks Formed in an Ancient Lake on Mars

NASA’s Curiosity rover continues to search for signs that Mars’ Gale Crater conditions could support microbial life. Photo credit: NASA/JPL-Caltech/MSSS.

We already know that water has existed on the surface of Mars but for how long? Curiosity has been searching for evidence for the long term presence of water on Mars and now, a team of researchers think they have found it. The rover has been exploring the Gale Crater and found it contains high concentrations of Manganese. The mineral doesn’t form easily on Mars so the team think it may have formed as deposits in an ancient lake. It is interesting too that life on Earth helps the formation of Manganese so its presence on Mars is a mystery.