Space News & Blog Articles

A team of astronomers have used a model of earthquakes to understand glitches in the timing of pulsars. Their results suggest that pulsars may have interiors that are far stranger than can be imagined.

Pulsars are perhaps the most accurate timekeepers in the entire universe. The pulsars themselves are really rapidly spinning neutron stars. Neutron stars are ultra-dense balls of atomic matter, usually no bigger than a few miles across with a mass a few times that of the Sun. 

When these neutron stars spin they blast out beams of radiation that draw circles around the sky. If the Earth happens to lie on one of those circles then we see a periodic flashing from those beams of radiation, creating a pulsar.

Pulsars will keep accurate rhythm for incredibly long periods of time. But occasionally they are known to glitch, when they suddenly shift from one rotation rate to another.

Astronomers do not fully understand what causes the glitches, but recently a team of researchers put together a model of how glitches operate. The model is based on earthquakes. Earthquakes have many causes, but one of them is when too much tension and pressure builds up between tectonic plates and the crust of the Earth buckles under the pressure. That results in an earthquake and a resettling of the material in the Earth.

Astronomers continue to hunt for the elusive kind of star known as Population III stars, the first stars to appear in the young universe. New research has revealed that the James Webb Space Telescope may be on the cusp of discovering them.

The stars that exist in the universe today are nothing like the first generation of stars to appear in the cosmos. With every generation of stars that lives and dies, more metals, which in astronomy are any element heavier than hydrogen and helium, add to the mix. The presence of these metals fundamentally changes the characteristics of the next generation of stars.

In contrast, the first generation of stars formed from an almost pristine mixture of pure hydrogen and helium using mechanisms that we do not yet fully understand. Members of the first generation of stars to appear in that primordial soup are known as Population III (or Pop III) stars, while intermediate stars are called Pop II stars, and then the latest generation of stars are called Pop I. Astronomers have searched for decades for any remnant populations of Pop III stars in the modern-day universe to no avail.

That means that they have to go back to earlier times to catch a glimpse of a Pop III star. But observations of the early epochs of the history of the universe are extremely difficult, and it’s unclear if our searches will be successful. Recently a team of astrophysicists conducted computer simulations of the formation of the first stars in the universe. They specifically looked to see if how long Pop III stars could continue forming in the young universe. 

They found that Pop III stars could still appear in relatively mature galaxies. The galaxies had to have reservoirs of pure hydrogen and helium still remaining. If the conditions were just right, Pop III stars could still form in those pockets. Even though those stars wouldn’t technically be amongst the first generation of stars to appear in the universe, they would still have many of the same properties.

MSL Curiosity is going about its business exploring Mars. The high-tech rover is currently exploring the sulphate-bearing unit on Mt. Sharp, the central peak in Mars’ Gale Crater. Serendipity placed a metal meteorite in its path.

The meteorite is made mostly of nickel and iron, and it has a name: Cacao. (Chocolate comes from cacao.) Cacao isn’t very large; it’s only about 30 cm (1 ft.) across. Curiosity has come across several meteorites since landing in Gale Crater in August 2012.

Cacao stands out visually from its surroundings. While the Martian surface is red from oxides, the meteorite is dark grey and metallic-looking. It’s also smooth and rounded, obvious signs that it passed through an atmosphere.

The image is a composite of six individual images taken with the rover’s Mastcam. Curiosity captured the images on Jan 27, 2023, the 3,724th Martian day, or sol, of the mission. The colours in the image have been corrected to match the lighting conditions as seen with human eyes on Earth.

The grooves and pits are called regmaglypts. They’re particularly interesting on iron meteorites. They formed when Cacao was travelling through the atmosphere. Even though Mars’ atmosphere is much thinner than Earth’s, it still creates enough friction to heat the meteorite’s surface. The regmaglypts are likely created by vortices of hot gas that melted the rock as it travelled through the atmosphere.

Black holes swallow everything—including light—which explains why we can’t see them. But we can observe their immediate surroundings and learn about them. And when they’re on a feeding binge, their surroundings become even more luminous and observable.

This increased luminosity allowed astronomers to find a black hole that was feasting on material only 800 million years after the Universe began.

Even with everything astrophysicists have learned, black holes are still mysterious. We know that the largest ones—supermassive black holes (SMBH)—reside in the centers of galaxies like the Milky Way. But the history of their formation, growth, and evolution is still shrouded in cosmic mystery.

Astrophysicists can infer the presence of these monsters in the heart of galaxies by the effect their massive gravitational pull has on nearby stars. But a better opportunity to study them is when they’re actively feeding. An actively feeding black hole is called an active galactic nucleus (AGN,) and when an AGN is extremely luminous, it’s called a quasar. As material swirls around their accretion disks, it heats up and emits x-rays.

Scientists have struggled to locate quasars in the early Universe, but it’s an important goal in black hole research. They need to find them in order to trace their development over time. One stumbling block in their efforts is the time period correlating with redshifts greater than z=6, about 12.716 billion years ago, or about one billion years after the Big Bang.