A Giant Stream of Stars is Flowing in Deep Space

The space between galaxies has long been considered a dead area. Single rogue stars may pop stars may pop up here or there, but the majority of this cosmic backward was considered empty by astronomers. But now, a paper from astronomers at various European and California institutions has found a trail of stars flowing between galaxies in a cluster.

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If Our Part of the Universe is Less Dense, Would That Explain the Hubble Tension?

Ten areas in the sky were selected as “deep fields” that the Dark Energy Camera imaged several times during the survey, providing a glimpse of distant galaxies and helping determine their 3D distribution in the cosmos. Credit: NSF/DES/NOIRLab/DOE/FNAL/AURA/University of Alaska Anchorage/
Ten areas in the sky were selected as “deep fields” that the Dark Energy Camera imaged several times during the survey, providing a glimpse of distant galaxies and helping determine their 3D distribution in the cosmos. Credit: NSF/DES/NOIRLab/DOE/FNAL/AURA/University of Alaska Anchorage/

In the 1920s, Edwin Hubble and Georges Lemaitre made a startling discovery that forever changed our perception of the Universe. Upon observing galaxies beyond the Milky Way and measuring their spectra, they determined that the Universe was expanding. By the 1990s, with the help of the Hubble Space Telescope, scientists took the deepest images of the Universe to date and made another startling discovery: the rate of expansion is speeding up! This parameter, denoted by Lambda, is integral to the accepted model of cosmology, known as the Lambda Cold Dark Matter (LCDM) model.

Since then, attempts to measure distances have produced a discrepancy known as the “Hubble Tension.” While it was hoped that the James Webb Space Telescope (JWST) would resolve this “crisis in cosmology,” its observations have only deepened the mystery. This has led to several proposed resolutions, including the idea that there was an “Early Dark Energy” shortly after the Big Bang. In a recent paper, an international team of astrophysicists proposed a new solution based on an alternate theory of gravity that states that our galaxy is in the center of an “under-density.”

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OSIRIS-REx Failed to Deploy its Drogue Chute Properly. Now NASA has Figured out Why

A training model of the OSIRIS-REx sample return capsule, August 30, 2023. Credit: NASA/Keegan Barber.
A training model of the OSIRIS-REx sample return capsule, August 30, 2023. Credit: NASA/Keegan Barber.

On September 24, 2023, NASA’s OSIRIS-REx mission returned a precious sample of rocky material from asteroid Bennu to Earth. The capsule landed safely under its main parachute, but it arrived more than a minute early. The cause: a small drogue parachute, designed to slow the spacecraft down prior to the main chute’s deployment, failed to open. After an investigation into the mishap, NASA believes they have determined the cause of the (happily non-catastrophic) failure.

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Astronomers Calculate Which Exoplanets Are Most Likely to Have Water

This illustration shows what the hot rocky exoplanet TRAPPIST-1 b could look like. A new method can help determine what rocky exoplanets might have large reservoirs of subsurface water. Credits: NASA, ESA, CSA, J. Olmsted (STScI)

Astronomers know of about 60 rocky exoplanets orbiting in the habitable zones of their stars. When they try to determine how habitable these planets might be, detecting water in their atmospheres plays a huge role. But what if there was another way of measuring the water content in these worlds?

Researchers are developing a way of modelling these worlds to determine how much water they have.

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Famed Halley’s Comet Passes Aphelion This Weekend

Halley's Comet
Halley's Comet in 1986.

Famous Halley’s Comet reaches a distant milestone this coming weekend.

It’s lonely out there in the frozen outer solar system. On Saturday, December 9th, that most famous of all comets 1P/Halley reaches a hallmark point on its 75-year journey through the solar system, reaching aphelion or its most distant point from the Sun.

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Another Fast Radio Burst is Coming from a Hypernebula. Also, Hypernebulae are a Thing

Radio image of the potential hypernebula powered by the repeating FRB 20190520B. The nebula is billions of lightyears from Earth, but a global network of radio telescopes has placed strong constraints on its size.
Image of Fast Radio Burst 20190520B

If nothing else catches your attention in the title then surely ‘hypernebula’ does! There are some amazing processes scattered around the cosmos, of particular interest are the fast radio bursts (FRB). These brief flashes of radiation happen without warning…until now. A team in the Netherlands have identified a second FRB as coming from within a hyper nebula – a dense and highly magnetised cloud of plasma that is illuminated by a powerful but unknown source!

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Eris Could be Slushier Than Pluto

Artist’s impression shows the distant dwarf planet Eris. Credit: ESO

In 2005, astronomer Mike Brown and his colleagues Chad Trujillo and David Rabinowitz announced the discovery of a previously unknown planetoid in the Kuiper Belt beyond Neptune’s orbit. The team named this object Eris after the Greek personification of strife and discord, which was assigned by the IAU a year later. Along with Haumea and Makemake, which they similarly observed in 2004 and 2005 (respectively), this object led to the “Great Planet Debate,” which continues to this day. Meanwhile, astronomers have continued to study the Trans-Neptunian region to learn more about these objects.

While subsequent observations have allowed astronomers to get a better idea of Eris’ size and mass, there are many unresolved questions about the structure of this “dwarf planet” and how it compares to Pluto. In a recent study, Mike Brown and University of California Santa Cruz professor Francis Nimmo presented a series of models based on new mass estimates for Eris’ moon Dysnomia. According to their results, Eris is likely differentiated into a convecting icy shell and rocky core, which sets it apart from Pluto’s conductive shell.

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Fermi has Found More than 300 Gamma-Ray Pulsars

Visualization of a fast-rotating pulsar. Credit: NASA's Goddard Space Flight Center Conceptual Image Lab

In June 2008, the Gamma-ray Large Area Space Telescope began surveying the cosmos to study some of the most energetic phenomena in the Universe. Shortly after that, NASA renamed the observatory in the Fermi Gamma-ray Space Telescope in honor of Professor Enrico Fermi (1901-1954), a pioneer in high-energy physics. During its mission, Fermi has addressed questions regarding some of the most mysterious and energetic phenomena in the Universe – like gamma-ray bursts (GRBs), cosmic rays, and extremely dense stellar remnants like pulsars.

Since it began operations, Fermi has discovered more than 300 gamma-ray pulsars, which have provided new insights into the life cycle of stars, our galaxy, and the nature of the Universe. This week, a new catalog compiled by an international team contains the more than 300 pulsars discovered by the Fermi mission – which includes 294 confirmed gamma-ray-emitting pulsars and another 34 candidates awaiting confirmation. This is 27 times the number of pulsars known to astronomers before the Fermi mission launched in 2008.

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We Should Hit Peak Solar Activity Next Year

SDO Sol
NASA SDO's view, of our tempestuous host star. NASA/SDO

You may be familiar with the solar cycle that follows a 22 year process shifting from solar minimum to maximum and back again.  It’s a cycle that has been observed for centuries yet predicting its peak has been somewhat challenging.  The Sun’s current cycle is approaching maximum activity which brings with it higher numbers of sunspots on its surface, more flares and more coronal mass ejections. A team from India now believe they have discovered a new element of the Sun’s magnetic field allowing them to predict the peak will occur early in 2024.

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