Universe Today

February 21, 2023February 21, 2023 by Nancy Atkinson

A 500-Meter-Long Asteroid Flew Past Earth, and Astronomers Were Watching

This collage shows six planetary radar observations of 2011 AG5 a day after the asteroid made its close approach to Earth on Feb. 3. With dimensions comparable to the Empire State Building, 2011 AG5 is one of the most elongated asteroids to be observed by planetary radar to date. Credit: NASA/JPL-Caltech

An asteroid the size of the Empire State Building flew past Earth in early February, coming within 1.8 million km (1.1 million miles) of our planet. Not only is it approximately the same size as the building, but astronomers found the asteroid – named 2011 AG5 — has an unusual shape, with about the same dimensions as the famous landmark in New York City.

“Of the 1,040 near-Earth objects observed by planetary radar to date, this is one of the most elongated we’ve seen,” said Lance Benner, principal scientist at JPL who helped lead the observations, in a JPL press release.

This extremely elongated asteroid has a length-to-width ratio of 10:3.

February 20, 2023February 20, 2023 by Matt Williams

All of Jupiter's Large Moons Have Auroras

Artist's concept of aurorae on Ganymede - auroral belt shifting may indicate a subsurface saline ocean. Credit: NASA/ESA

Jupiter is well known for its spectacular aurorae, thanks in no small part to the Juno orbiter and recent images taken by the James Webb Space Telescope (JWST). Like Earth, these dazzling displays result from charged solar particles interacting with Jupiter’s magnetic field and atmosphere. Over the years, astronomers have also detected faint aurorae in the atmospheres of Jupiter’s largest moons (aka. the “Galilean Moons“). These are also the result of interaction, in this case, between Jupiter’s magnetic field and particles emanating from the moons’ atmospheres.

Detecting these faint aurorae has always been a challenge because of sunlight reflected from the moons’ surfaces completely washes out their light signatures. In a series of recent papers, a team led by the University of Boston and Caltech (with support from NASA) observed the Galilean Moons as they passed into Jupiter’s shadow. These observations revealed that Io, Europa, Ganymede, and Callisto all experience oxygen-aurorae in their atmospheres. Moreover, these aurorae are deep red and almost 15 times brighter than the familiar green patterns we see on Earth.

February 20, 2023February 20, 2023 by Carolyn Collins Petersen

Some Elements Arrived on Earth by Surfing Supernova Shock Waves

Neutron-neutron star mergers are one way that heavy radioactive isotopes of elements found on Earth could be created. Courtesy ESO.

When stars die, they spread the elements they’ve created in their cores out to space. But, other objects and processes in space also create elements. Eventually, that “star stuff” scatters across the galaxy in giant debris clouds. Later on—sometimes millions of years later—it settles onto planets. What’s the missing link between element creation and deposition on some distant world?

February 20, 2023February 20, 2023 by Nancy Atkinson

Follow Perseverance on Its Mars Journey With This Two-Year Timelapse

Looking Back at Perseverance's Second Science Campaign: This image of the floor of Jezero Crater was taken by one of the Navcam imagers aboard NASA’s Perseverance Mars rover on Feb. 5, 2023, the 698th Martian day, or sol, of the mission. Credits: NASA/JPL-Caltech.

Hard to believe, but the Perseverance Rover has begun its third year exploring Mars. On Feb. 18, 2021, Perseverance rover survived the harrowing landing at Jezero Crater, and almost immediately, began an expedition to collect a geologically diverse set of rock samples, ones that could help answer the question if Mars once had ancient microbial life.

JPL and NASA put together a wonderful two-year animation of images from the rover’s Front Left Hazard Avoidance Camera to celebrate Percy’s landing anniversary.

February 20, 2023February 20, 2023 by Nancy Atkinson

If Planet 9 has Moons, Would That Help Us Find It?

Artist's concept of the hypothetical "Planet Nine." Could it have moons? Credit: NASA/JPL-Caltech/Robert Hurt

Planet 9 continues to remain elusive. This potential super-Earth-sized object in the outer Solar System is only hypothetical, as something out there appears to be gravitationally influencing several Kuiper Belt Objects into unusual orbits. Whatever or wherever it may be, Planet 9 has yet to be found, despite several different hypotheses and numerous observational searches.

But what if Planet 9 has moons? Could they help us find it? A new paper speculates that any moons orbiting the theoretical planet could provide indirect clues to the location of Planet 9, while revealing some basic properties of this mysterious object.

February 20, 2023February 19, 2023 by Alan Boyle

Happy Presidents Day: George Washington’s Hair Set to Go to Deep Space

Illustration: Vulcan Centaur rocket launch — An artist's conception shows a Vulcan Centaur rocket lifting off. (United Launch Alliance Illustration)

If it turns out that a future extraterrestrial invasion force is headed by a clone of George Washington, we’ll have only ourselves to blame.

Admittedly, that would be the unlikeliest outcome of a space shot that aims to send hair samples from America’s first president — and from Presidents Dwight Eisenhower, John F. Kennedy and Ronald Reagan — into deep space.

The samples, which include bits of DNA, are to be included on Houston-based Celestis’ “Enterprise Flight,” a memorial space mission that will also carry DNA and cremated remains from the late astronaut Philip Chapman, Star Trek celebrities and scores of Celestis clients. The time capsule will be sent into space later this year as a secondary payload aboard United Launch Alliance’s Vulcan Centaur rocket, and eventually settle into stable orbit around the sun.

February 19, 2023February 19, 2023 by Anton Pozdnyakov

Meteor Explodes Over English Channel, Moon Breakthrough, Dark Matter Galaxy

Blue Origin wants to build solar panels on the Moon, out of the Moon, SpaceX sold its floating landing pads, and another asteroid hits Earth exactly where and when astronomers predicted.

February 18, 2023February 18, 2023 by Nancy Atkinson

ESA is Building an Early Warning System for Dangerous Asteroids

A graphic showing the concept for the NEOMIR orbiting observatory will act as an early warning system to detect and monitor any asteroid coming towards Earth from the Sun’s direction. Credit: ESA.

The European Space Agency is working on a new mission that would act as an early warning system for dangerous, hard-to-see asteroids. Called NEOMIR (Near-Earth Object Mission in the InfraRed), the spacecraft would orbit between the Earth and the Sun at the L1 Lagrange Point, finding space rocks that otherwise get lost in the glare of the Sun.

February 17, 2023February 17, 2023 by Matt Williams

Are Black Holes the Source of Dark Energy?

An illustration of cosmic expansion. Credit: NASA's Goddard Space Flight Center Conceptual Image Lab

By the 1920s, astronomers learned that the Universe was expanding as Einstein’s Theory of General Relativity predicted. This led to a debate among astrophysicists between those who believed the Universe began with a Big Bang and those who believed the Universe existed in a Steady State. By the 1960s, the first measurements of the Cosmic Microwave Background (CMB) indicated that the former was the most likely scenario. And by the 1990s, the Hubble Deep Fields provided the deepest images of the Universe ever taken, revealing galaxies as they appeared just a few hundred million years after the Big Bang.

Over time, these discoveries led to an astounding realization: the rate at which the Universe is expanding (aka. the Hubble Constant) has not been constant over time! This led to the theory of Dark Energy, an invisible force that counteracts gravity and causes this expansion to accelerate. In a series of papers, an international team of researchers led by the University of Hawaii reported that black holes in ancient and dormant galaxies were growing more than expected. This constitutes (they claim) the first evidence that black holes could be the source of Dark Energy.

February 17, 2023February 17, 2023 by Evan Gough

Galaxies Aren’t Just Stars. They’re Intricate Networks of Gas and Dust

This image taken by the NASA/ESA/CSA James Webb Space Telescope shows the spiral galaxy NGC 1433. Image Credit: NASA, ESA, CSA, and J. Lee (NOIRLab), A. Pagan (STScI)

Astronomers have studied the star formation process for decades. As we get more and more capable telescopes, the intricate details of one of nature’s most fascinating processes become clearer. The earliest stages of star formation happen inside a dense veil of gas and dust that stymies our observations.

But the James Webb Space Telescope sees right through the veil in its images of nearby galaxies.