Astronomers are Hoping the Event Horizon Telescope saw Pulsars Near the Milky Way's Supermassive Black Hole

By Brian Koberlein - September 02, 2023 09:55 AM UTC | Black Holes
The Event Horizon Telescope is a collection of radio telescopes across the globe that simultaneously gathered data about the Milky Way's supermassive black hole, acting as a single telescope the size of planet Earth. This revealed the galaxy's heart in unprecedented detail, helping to confirm the black hole's event horizon and prove some of Einstein's predictions about General Relativity. But if those observations happened to contain any signals from pulsars in the area, it would allow for even more precise measurements, as if there were atomic clocks orbiting Sgr A*.
Continue reading

If Earth Was an Exoplanet, JWST Would Know There's an Intelligent Civilization Here

By Brian Koberlein - September 01, 2023 11:51 AM UTC | Astrobiology
JWST is the most powerful instrument astronomers have to study the atmospheres of exoplanets, looking for trace gases that might indicate life on another world. What if Earth was an exoplanet orbiting a nearby star? What could JWST learn about our planet? In a new study, astronomers took observations of Earth from various spacecraft and then simulated what JWST would see if it got our home planet in the crosshairs. The telescope could detect various chemicals, from water vapor to methane, but it could also sense the presence of chlorofluorocarbons resulting from our industrial infrastructure.
Continue reading

Do Advanced Civilizations Know We're Here?

By Brian Koberlein - August 31, 2023 10:41 AM UTC | Astrobiology
Although humans have only sent a couple of tentative signals into space, many are concerned about the risks. Should we let alien civilizations know we're here? According to a new paper, humanity has already been broadcasting its existence for thousands of years, and civilizations with advanced enough technology should be able to observe us. It's science fiction to us, but megastructure space telescopes could have baselines of millions of kilometers, powerful enough to detect structures on the surface of Earth from thousands of light-years away.
Continue reading

It's Time for a Gravitational Wave Observatory in the Southern Hemisphere

By Brian Koberlein - August 30, 2023 10:48 AM UTC | Physics
All current and planned gravitational wave observatories are located in the northern hemisphere, in the US, India, Europe, and Japan. Even the next-generation observatories like Cosmic Explorer 40-km and the Einstein Telescope will be in the north. But a telescope in the southern hemisphere would provide a much larger baseline, allowing the detection of fainter gravitational waves. A new paper makes the case for building an observatory south of the equator.
Continue reading

Astronomers Precisely Measure a Black Hole's Accretion Disk

By Brian Koberlein - August 29, 2023 12:56 PM UTC | Black Holes
Actively feeding supermassive black holes are known as quasars, and they can outshine all the stars of their host galaxy. Part of their brightness comes from the accretion disk surrounding the black hole, but they're hard to image directly because quasars are so far away. New data from one of the world's largest telescopes has managed this feat, detecting near-infrared emission lines that mark significant regions in the accretion disk in a quasar.
Continue reading

The Early Universe Should Be Awash in Active Galaxies, but JWST Isn't Finding Them

By Brian Koberlein - August 27, 2023 12:47 PM UTC | Cosmology
Astronomers have found supermassive black holes in the centers of most galaxies. To get the black holes we see today, they must have been feeding in the past, packing on the mass to grow so big. But, a recent survey with JWST failed to turn up as many active galactic nuclei as astronomers expected. This just deepens the mystery. How did mature galaxies like the Milky Way get their black holes if they didn't go through this feeding period?
Continue reading

Pulsars Detected the Background Gravitational Hum of the Universe. Now Can They Detect Single Mergers?

By Brian Koberlein - August 26, 2023 11:35 AM UTC | Physics
After over a decade of observations of pulsars, astronomers could finally tease out the gravitational wave background of the Universe, the combined signal from merging supermassive black holes. But it was just the general presence of mergers, not specific events. A new paper proposes that the same pulsars could next be used to detect the gravitational waves from individual merging supermassive black holes. The more nearby pulsars astronomers can find, the more accurate their measurements will become.
Continue reading

A Giant Black Hole Destroyed a Star and Threw the Pieces Into Space

By Brian Koberlein - August 25, 2023 12:17 PM UTC | Black Holes
A pair of X-ray telescopes have observed the messy aftermath of a star that came too close to a supermassive black hole 290 million light-years away. It's believed that the star had three times the mass of the Sun, so this was one of the largest tidal disruption events ever seen. Although the black hole consumed some of the star, most of its guts were thrown into the surrounding space, polluting the region with the chemicals that allowed astronomers to estimate its stellar mass.
Continue reading

TESS Has Found Thousands of Possible Exoplanets. Which Ones Should JWST Study?

By Brian Koberlein - August 24, 2023 01:43 PM UTC | Exoplanets
JWST has demonstrated how well it can analyze the atmosphere of exoplanets, revealing carbon dioxide, water vapor, and sulfur compounds. The hope, of course, is that it might be able to find evidence of biosignatures. Astronomers have found over 5,000 confirmed exoplanets, and TESS has turned up 4,000 candidate exoplanets. With this enormous catalog of confirmed and potential planets, which are high priorities that JWST should be pointed at?
Continue reading

The Irony. ClearSpace-1 Couldn't Clean up Space Debris Because its Target Already Got hit by Space Debris, Creating Even More Space Debris.

By Brian Koberlein - August 23, 2023 09:49 AM UTC | Space Policy
The European Space Agency's ClearSpace-1 satellite was zeroing in on the spent payload adaptor from a 2013 rocket launch. Its task would be to extend arms, grab the chunk of debris, hug it tightly, and then pull it back into the Earth's atmosphere, de-orbiting and removing it from low-Earth orbit. On August 10th, mission controllers detected multiple pieces of space debris near its target - debris that was probably dislodged from it in the recent past. They're now scrutinizing the situation to plan their next step in the mission.
Continue reading

When the Sun Dies, it Could Produce a Fantastic Ring in Space, Like This New Image From JWST

By Brian Koberlein - August 22, 2023 02:55 PM UTC | Stars
We recently got a new image of the famous Ring Nebula from JWST using its NIRCam instrument. This week we got an update taken with MIRI. The Ring Nebula is a perfect example of a planetary nebula, where a dying star throws its outer layers off into space. The new images reveal 20,000 individual clumps of dense molecular gas, each as massive as Earth. There is a narrow band of hydrocarbons in the ring, which surprised astronomers with its presence. The Ring Nebula is only 2,200 light-years from Earth, which makes it the ideal object to study, giving us clues about the future of our own Sun.
Continue reading

A New Way to Measure the Expansion Rate of the Universe: Redshift Drift

By Brian Koberlein - August 19, 2023 01:37 PM UTC | Cosmology
Almost all the galaxies in the Universe are speeding away from us because of the Big Bang and the acceleration of dark energy. One technique to measure this expansion is redshift, seeing how light is reddened over time as its wavelength stretches out. But every observation astronomers can make is a snapshot, measuring the redshift now. But an intriguing idea is to measure how the redshift changes over time as a galaxy's movement accelerates. It's called "redshift drift" and requires an exact series of measurements over time.
Continue reading

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

By Brian Koberlein - August 18, 2023 02:39 PM UTC | Stars
Stars begin as giant clouds of gas and dust that pull together through mutual gravity into a dense protostar. At some point, the intense pressure and temperature cause fusion in the star's core, where lighter elements, like hydrogen, are fused into heavier elements, like helium. When the Sun runs out of one type of fuel, it shifts to the next type and begins the process again, with the heaviest stars reaching iron. A new simulation shows a portion of the interior of a star as it completes one of these stellar phases.
Continue reading