This Distant Galaxy Cluster is Totally Relaxed, Unharassed for a Billion Years

Astronomers have discovered a galaxy cluster with an important characteristic; it's “relaxed, meaning that it shows no signs of having been disrupted by violent collisions with other clusters of galaxies. This composite image contains X-rays from Chandra (blue), which helped identify SPT2215 along with other telescopes, and data from Hubble (cyan and orange). Image Credit: X-ray: NASA/CXC/MIT/M. Calzadilla; UV/Optical/Near-IR/IR: NASA/STScI/HST; Image processing: N. Wolk

In the span of a human lifetime, much of the Universe seems unchanging. But that’s an illusion; things are always changing, and that fact can make galaxies and the clusters they reside in very unruly places due to mergers and collisions.

However, some galaxy clusters seem much calmer than others.

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A New Simulation Reveals One Entire Stage of a Star's Life

The interior structure of our Sun. The dynamo generating a magnetic field could lie very close to the solar surface. Credit: Kelvin Ma, via Wikipedia
The interior structure of our Sun. The dynamo generating a magnetic field could lie very close to the solar surface. Credit: Kelvin Ma, via Wikipedia

Nuclear fusion is at the center of stellar evolution. Most of a star’s life is a battle between gravity and nuclear power. While we understand this process on a broad scale, many of the details still elude us. We can’t dive into a star to see its nuclear furnace, so we rely on complex computer simulations. A recent study has made a big step forward by modeling the entire fusion cycle of a single element.

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Comet P1 Nishimura Could Be Bright Over the Next Few Weeks

Comet P1 Nishimura
Comet P1 Nishimura from August 15th. Credit: Michael Jaeger.

New Comet P1 Nishimura graces the August dawn sky…but how bright will it get?

Hello. In a predictable clockwork Universe, a new comet is always the one wildcard that can over- or under-perform expectations. The most dramatic ones often crop up with scant warning: witness Comet IRAS-Araki-Alcock in 1983, and Comet B2 Hyakutake in 1996.

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The Largest Impact Crater on Earth, 520 km Across, Might Be Hiding Under Australia

Asteroid impacts have arguably killed off more species than almost any other type of disaster since life began on Earth. The most famous of these, the Chicxulub impactor, killed the dinosaurs about 65 million years ago, along with 76% of all species on the planet at the time. But that was by no means the worst disaster; as far as we can tell, it wasn’t even the biggest asteroid. That title currently goes to the Vredefort crater in South Africa. Coming in at over 300 kilometers wide, it was the largest asteroid crater so far found, at least when it was formed about 2 billion years ago. But that might be about to change if a theory from Andrew Glikson and Tony Yeates of New South Wales is correct. They have found what they believe to be the biggest impact crater on Earth since the Late Heavy Bombardment in their own Australian province of New South Wales, and they think it might have caused one of the other five mass extinction events.

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No Surprise, July 2023 Was the Hottest Month on Record Since 1880

This map shows global temperature anomalies for July 2023 according to the GISTEMP analysis by scientists at NASA’s Goddard Institute for Space Studies. Temperature anomalies reflect how July 2023 compared to the average July temperature from 1951-1980. Credit: NASA’s Goddard Institute for Space Studies
This map shows global temperature anomalies for July 2023 according to the GISTEMP analysis by scientists at NASA’s Goddard Institute for Space Studies. Temperature anomalies reflect how July 2023 compared to the average July temperature from 1951-1980. Credit: NASA’s Goddard Institute for Space Studies

In case you missed it, the weather’s been hot. From warmer-than-usual temperatures in northern climes to melting ice sheets in the polar regions, July 2023 was a record-breaking month. That’s not just some random perception. NASA has been keeping records and the agency confirms what most of us have observed for ourselves. It was a warm one.

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This Sure Looks Like the Movements of a Glacier Across Ancient Mars

HiRISE image showing rough terrain possibly shaped by ancient glaciers. Credit: NASA/JPL-Caltech/UArizona

It is a scientific certainty that Mars was once a much different place, with a denser atmosphere, warmer temperatures, and where water once flowed. Evidence of this past is preserved in countless surface features, ranging from river channels and alluvial deposits to lakebeds. However, roughly 4 billion years ago, the planet began to change into what we see today, an extremely cold and desiccated environment. Between all that, it is possible Mars experienced glacial and interglacial periods, which is evidenced by images like the one taken by the NASA Mars Reconnaissance Orbiter (MRO) shown above.

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We Might Be Able to Measure Dark Energy Through the Milky Way's Collision With Andromeda

How the sky might look when the Andromeda galaxy approaches the Milky Way. Credit: NASA; ESA; Z. Levay and R. van der Marel, STScI; T. Hallas; and A. Mellinger

The Universe is expanding, and it’s doing so at an ever-increasing pace. Whether due to a dark energy field throughout the cosmos or due to a fundamental of spacetime itself, the cosmos is stretching the space between distant galaxies. But nearby galaxies, those part of our local group, are moving closer together. And how they are falling toward each other could tell us about the nature of cosmic expansion.

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This Brown Dwarf is 2,000 Degrees Hotter Than the Sun

exoplanet hot jupiter transiting its star
This artist’s impression shows an ultra-hot exoplanet as it is about to transit in front of its host star. Credit: ESO

Astronomers have discovered an intense binary star system located about 1,400 light years away. It contains a brown dwarf with 80 times the mass of Jupiter which is bound closely with an incredibly hot white dwarf star. Observations have shown the brown dwarf is tidally locked to the white dwarf, allowing the daytime surface temperatures on the brown dwarf to reach 8,000 Kelvin (7,700 Celsius, 14,000 Fahrenheit) — which is much hotter than the surface of the Sun, which is about 5,700 K (5,427 C, 9,800 F). The brown dwarf’s nightside, on the other hand, is about 6,000 degrees K cooler.

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The Sun Gets Meteor Showers Too, But They’re Very Different

SolO view in the EUV on 30 March 2022 showing a partial section of the Sun with gas at 1 million degrees. Credit Patrick Antolin. Background image: ESA/Solar Orbiter EUI/HRI Licence type Attribution (CC BY 4.0)

The Sun dominates the Solar System in almost every way imaginable, yet much of its inner workings have been hidden from humanity. Over the centuries, and especially in the last few decades, technological advancements allowed us to ignore our mothers’ exhortations and stare at the Sun for as long as we want. We’ve learned a lot from all those observations.

A new study shows how the Sun experiences its own ‘meteor showers.’

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New Horizons is So Far Away, it Can Measure the True Darkness of the Universe

Artist view of the New Horizons spacecraft against a sea of stars. Credit: Serge Brunier/Marc Postman/Dan Durda
Artist view of the New Horizons spacecraft against a sea of stars. Credit: Serge Brunier/Marc Postman/Dan Durda

Just how dark is the night sky?

If you step outside during a moonless night and look up, it probably doesn’t look that dark at all. Streetlights or nearby porch lights fill the air with a background glow, particularly if they happen to be bluish-white LEDs. Light pollution in your neighborhood is likely so bad that you can only see a few bright stars. Even in somewhat rural areas, our skies are so bright that the Milky Way isn’t really visible. In North America and Europe, only about a quarter of children have seen the Milky Way.

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