Carolyn Collins Petersen, Author at Universe Today

October 2, 2022October 2, 2022 by Carolyn Collins Petersen

The Bright Core of This Spiral Galaxy Reveals an Actively Feeding Supermassive Black Hole

spiral galaxy with black hole — The stately sweeping spiral arms of the spiral galaxy NGC 5495 as seen by the NASA/ESA Hubble Space Telescope’s Wide Field Camera 3 in this image.

Hubble Space Telescope observes a lot of galaxies. Some of them are wild-looking while others seem fairly placid. Recently, it looked at NGC 5495, which lies about 300 million light-years away from Earth. You wouldn’t know just by looking at it, but this galaxy has some pretty hot action happening in its core.

September 30, 2022September 30, 2022 by Carolyn Collins Petersen

Two “Super Mercury” Exoplanets Found in a Single System

Mercury gives a clue to Super-Mercuries — Astronomers have found a star system with two planets like Mercury, but bigger. Our own Mercury could supply clues to their composition and formation. (Credit: NASA/Johns Hopkins University/Applied Physics Laboratory.Carnegie Institution of Washington).

There’s a star system out there with three super-Earth planets and two super-Mercuries. Super-Earths are fairly familiar types of exoplanets, but super-Mercuries are rare. Those are planets with the same composition as our own Mercury, but larger and denser. Yet, here’s HD 23472, showing off two of eight known super-Mercuries in the galaxy.

September 29, 2022September 29, 2022 by Carolyn Collins Petersen

The Moon was Pummeled by Asteroids at the Same Time the Dinosaurs Died. Coincidence?

Earth and possibly its Moon were hit by impactors that killed off the dinosaurs — Artistic rendition of the Chicxulub impactor striking ancient Earth, with Pterosaur observing. Could pieces of the same impact swarm have hit the Moon, too? Credit: NASA

It only takes a quick look at the Moon to see its impact-beaten surface. There are craters everywhere. Some of those impact sites apparently date back to the same time some very large asteroids were whacking Earth. One of them formed Chixculub Crater under the Yucatan Peninsula. That impact set in motion catastrophic events that wiped out much of life on Earth, including the dinosaurs.

September 29, 2022September 29, 2022 by Carolyn Collins Petersen

DART Impact Seen by Hubble and Webb

DART hits an asteroid. — For the first time, the NASA/ESA/CSA James Webb Space Telescope and the NASA/ESA Hubble Space Telescope took simultaneous observations of the same target. These images, Hubble on left and Webb on the right, show observations of Dimorphos several hours after NASA’s Double Asteroid Redirection Test (DART) intentionally impacted the moonlet asteroid. Courtesy NASA, ESA, CSA, and STScI

What happens when you whack a little asteroid with an even littler spacecraft? People around the world watched on the 26th of September when the DART mission smashed into the side of Dimorphos. This tiny worldlet is a companion asteroid to Didymos. It was the world’s first test of the kinetic impact technique, using a spacecraft to deflect an asteroid by modifying its orbit. Amateur observer networks and professional observatories tracked the meetup from the ground. In a first, both Hubble Space Telescope (HST) and the James Webb Space Telescope (JWST) took simultaneous images and data.

September 28, 2022September 28, 2022 by Carolyn Collins Petersen

Alaska Has New Lakes. Unfortunately, They’re Releasing a lot of Methane

methane in a thermokarst lake — Big Trail Lake is one of Alaska’s newest lakes and one of the largest methane emission hotspots in the Arctic. Credit: NASA / Katie Jepson

A NASA scientist is finding newly formed lakes in Alaska that are belching greenhouse gases at a high rate. The main one is methane, a gas many people use in their natural gas-fueled grills. She’s tracking these emissions in one of Earth’s most remote regions—the Arctic. It has millions of lakes, many of them hundreds or thousands of years old. But, only the youngest of them are releasing high amounts of methane. And that is due to the effects of climate change on these delicate environments.

September 27, 2022September 27, 2022 by Carolyn Collins Petersen

Another Ghostly Spiral Galaxy Revealed by JWST

JWST and IC 5332 — This image of the spiral galaxy IC 5332, taken by the NASA/ESA/CSA JWST observatory, with its MIRI instrument. Courtesy ESA/Webb, NASA & CSA, J. Lee and the PHANGS-JWST and PHANGS-HST Teams

The famous American baseball player once said, “You can observe a lot just by watching.” That’s certainly true of the JWST, which just released its latest “spider-web” image of a distant galaxy. It “watched” IC 5332 using the onboard Mid-InfraRed Instrument (MIRI). In the process it observed spectacular details not easily seen in visible light.

September 27, 2022September 27, 2022 by Carolyn Collins Petersen

Climate Change is Making the Skies Worse for Astronomy

climate change could affect observatories like these on Mauna Kea in Hawaii. — The top of Mauna Kea is a prime site for telescopes, as shown in this image. It boasts clear, dry atmospheric conditions. Global climate change could alter that. Image courtesy Mauna Kea Observatories

Light pollution. Satellite trains and radio frequency interference. Encroaching civilization. These all pose threats to ground-based astronomy. But, did anyone ever think that global climate change might wreak havoc on observatories? It turns out the answer is “yes.”

September 25, 2022September 25, 2022 by Carolyn Collins Petersen

Gravity Really Tangled up the Light From a Distant Quasar

quasar lensed — The SDSS J1004+4112 gravitational lens creates five images of a distant quasar. Credit: European Space Agency, NASA, Keren Sharon (Tel-Aviv University) and Eran Ofek (CalTech))

Way back in 1979, astronomers spotted two nearly identical quasars that seemed close to each other in the sky. These so-called “Twin Quasars” are actually separate images of the same object. Even more intriguing: the light paths that created each image traveled through different parts of the cluster. One path took a little longer than the other. That meant a flicker in one image of the quasar occurred 14 months later in the other. The reason? The cluster’s mass distribution formed a lens that distorted the light and drastically affected the two paths.

September 23, 2022September 23, 2022 by Carolyn Collins Petersen

There’s a Blob of Gas Orbiting Around the Milky Way’s Supermassive Black Hole

The Atacama Large Millimeter/submillimeter Array (ALMA) looked at Sagittarius A*, (image of Sag A* by the EHT Collaboration) to study something bright in the region around Sag A*. Credit: ESO/José Francisco Salgado.

Sagittarius A* (Sag A) is usually a pretty quiet object, as supermassive black holes go. It’s not wildly active, like the object at the heart of M87, for example. But, every once in a while, there’s a little action in its neighborhood. Right now, there appears to be a hot blob of gas running rapidly in circles around the black hole. Astronomers detected it using the Atacama Large Millimeter Array (ALMA) in Chile. The data from that radio astronomy facility tells them more about the environment around Sag A*.

September 21, 2022September 21, 2022 by Carolyn Collins Petersen

Habitable Planets Will Most Likely be Cold, Dry “Pale Yellow Dots”

An artist's concept of K2-18b, a super-Earth exoplanet that could support life. But, not all habitable planets are pale blue dots. Some are dry and yellow. Courtesy STScI

Remember all the habitable planets we’ve seen in science fiction movies? There’s wintry Hoth, for example, and overwhelmingly hot Dune. The folks in Interstellar visited an ocean world and a desolate rocky world. For all their differences, these places were still what they call on Star Trek M-class habitable worlds. Sure they weren’t all like Earth, but that made them excitingly alien for the lifeforms they did support. In the real universe, it seems that alien worlds not quite like ours could be the norm. Earth could be the real alien world.