Astronomy Archives

August 12, 2022August 12, 2022 by Matt Williams

Why Betelgeuse Dimmed

Credit: NASA, ESA, and E. Wheatley (STScI)

Betelgeuse, the big reddish star that is the second brightest point in the constellation Orion (after Rigel), has been puzzling astronomers for years. Starting in October 2019, Belegeuse began to dim considerably, eventually reaching 1/3rd of its normal brightness a few months later. And then, just as mysteriously, it began to brighten again and (as of February 2022) has remained in a normal brightness range. The most likely reason appeared to be a circumstellar dust cloud rather than any changes in the star’s intrinsic brightness.

Using data from NASA’s Hubble Space Telescope (HST) and several other observatories, astronomers have concluded that a Surface Mass Ejection (SME) was the culprit. This event occurred in 2019 when Betelgeuse released a substantial mass of material that cooled to form a circumsolar dust ring, obscuring the star. In contrast to what regularly happens with our Sun during a Coronal Mass Ejections (CME), Betelgeuse ejected roughly 400 billion times as much mass as a typical CME. This is the first time something of this nature has been seen in a normal star’s behavior.

August 12, 2022August 12, 2022 by David Dickinson

Starlink Satellites Are Still Bright

The new generation of Starlink satellites remain above the accepted brightness threshold.

It’s one of the stranger sights of the modern Space Age. Recently, we found ourselves under the relatively dark skies of southern Spain. Sure enough, within a few minutes, we caught sight of a chain of flashing ‘stars’ winking in and out of view in quick succession.

August 11, 2022August 12, 2022 by Carolyn Collins Petersen

Here’s a Sneak Preview of What It’ll Look Like When the Milky Way and Andromeda Galaxies Collide

When big spiral galaxies collide, they don’t end up as one really big spiral. Instead, they create a humongous elliptical galaxy. That’s the fate awaiting the Andromeda Galaxy and our Milky Way. They’ll tangle in a galactic dance starting in a few billion years. Want to know what it’s going to look like when the action starts? The Gemini North telescope in Hawai’i just released a stunning image of two galaxies like ours tangling it up. These are NGC 4568 and NGC 4567 and their interaction provides a sneak peek at our galactic neighborhood in the distant future.

August 11, 2022August 11, 2022 by Matt Williams

The Youngest Exoplanet Ever Seen?

Credit: ALMA (ESO/NAOJ/NRAO), S. Dagnello (NRAO/AUI/NSF)

According to the most widely-accepted theory by astronomers, planetary systems begin as massive clouds of gas and dust (aka. a nebula) that experience gravitational collapse at the center to form new stars. The remaining matter in the system forms a “circumplanetary disk” around the star, which gradually accretes to form young planets. Studying disks in the earliest stages of planetary formation could help answer some hard questions about how the Solar System formed over 4.5 billion years ago.

Studying these disks requires observatories capable of capturing light in the far-infrared part of the spectrum – precisely what the Atacama Large Millimeter/submillimeter Array (ALMA) was built for. While studying a young star (AS 209) located about 395 light-years from Earth in the constellation Ophiuchus, a team of scientists observed a circumplanetary disk that appeared to have a Jupiter-mass planet embedded in it. This could constitute the youngest exoplanet ever detected, and its continued study could provide a treasure-trove of data for astronomers.

August 10, 2022August 10, 2022 by Matt Williams

SpaceX Super Heavy Fires Just one of its Engines. Imagine What it’ll be Like When it Fires all 33

Engineers and technicians at the SpaceX Starbase in Boca Chica, Texas, are working on getting the fully-stacked Starship and Super Heavy prototypes ready for their orbital launch test. The most recent step consisted of a static fire test with the BN7 Super Heavy prototype, where the booster was placed on the orbital launch pad and fired one of its thirty-three Raptor 2 engines. News of the test was shared via SpaceX’s official Twitter account and showed the BN7 blasting the launch pad, leading many to wonder what the orbital launch test will look like!

Team at Starbase completed a single Raptor engine static fire test of Super Heavy Booster 7 on the orbital launch pad pic.twitter.com/16R7eE985V
— SpaceX (@SpaceX) August 9, 2022

August 10, 2022August 13, 2022 by Paul M. Sutter

Astronomers Were Fortunate Enough to Catch a Neutron Star Merging With Another Star

A team of astronomers have followed the evolution of a short duration gamma ray burst, one of the most intense explosions in the entire universe. This discovery makes a breakthrough for further observations of these rare events.

August 9, 2022August 13, 2022 by Paul M. Sutter

Gravitational Waves Near a Neutron Star Could Generate Photons

Artist view of colliding neutron stars. Credit: ESO/L. Calçada/M. Kornmesser

In addition to their intense magnetic fields and copious output of x-ray radiation, neutron stars might have one more trick up their sleeves. They might be able to turn gravitational waves into an extra source of photons.

August 8, 2022August 8, 2022 by Carolyn Collins Petersen

Astronomers List 88 Distant Galaxies They Want to Look at With JWST. Some Are Less Than 200 Million Years Old.

SMACS cluster from JWST shows evidence of dark matter — The galaxy cluster SMACS 0723 as seen by NIRCam on JWST. It's gravitational lensing properties (from its mass and from the mass of dark matter) are helping astronomers identify 88 distant galaxies in this field of view for further study. Courtesy NASA, ESA, CSA, STScI

Way back in the earliest ages of the universe, the first galaxies were born. Astronomers want to know more about them. They’re especially interested to know exactly when these distant galaxies formed and what their stars were like. Now that JWST is a working observatory, astronomers are excited to use its data to explore those early epochs. They’re eager to see the most distant objects, and—as seems likely—do a rejiggering of the cosmic timeline after the Big Bang.

August 7, 2022August 7, 2022 by Carolyn Collins Petersen

Dwarf Galaxies Found Without Influence From Dark Matter

Dwarf galaxy in Fornax. — The dwarf galaxy NGC1427A flies through the Fornax galaxy cluster and undergoes disturbances which would not be possible if this galaxy were surrounded by a heavy and extended dark matter halo, as required by standard cosmology. Courtesy ESO.

Ask astronomers about dark matter and one of the things they talk about is that this invisible, mysterious “stuff” permeates the universe. In particular, it exists in halos surrounding most galaxies. The mass of the halo exerts a strong gravitational influence on the galaxy itself, as well as on others in the neighborhood. That’s pretty much the standard view of dark matter and its influence on galaxies. However, there are problems with the idea of those halos. Apparently, some oddly shaped dwarf galaxies exist that look like they have no halos. How could this be? Do they represent an observationally induced challenge to the prevailing ideas about dark matter halos?

August 5, 2022August 5, 2022 by Fraser Cain

I Asked an AI to Dream the Solar System as Food

Jupiter, as a Sandwich. Credit: Midjourney AI

As soon as I saw these new artificial intelligence image creation tools, like DALL-E, I wanted to see how well they’d work for generating space and astronomy images. I’m still on the waiting list for DALL-E 2, so I don’t have any feedback to give there, but I signed up for Midjourney AI, played around with the free account, and then signed up for a full paid account, so I could test out its capabilities.