Universe Today

November 18, 2023November 18, 2023 by Matt Williams

Under Some Conditions, Comets Could Deliver Organic Molecules to Planets

This artwork shows a rocky planet being bombarded by comets. Image credit: NASA/JPL-Caltech

Approximately 4.1 to 3.8 billion years ago, the planets of the inner Solar System experienced many impacts from comets and asteroids that originated in the outer Solar System. This is known as the Late Heavy Bombardment (LHB) period when (according to theory) the migration of the giant planets kicked asteroids and comets out of their regular orbits, sending them hurtling towards Mercury, Venus, Earth, and Mars. This bombardment is believed to have distributed water to the inner Solar System and maybe the building blocks of life itself.

According to new research from the University of Cambridge, comets must travel slowly – below 15 km/s (9.32 mi/s) – to deliver organic material onto other planets. Otherwise, the essential molecules would not survive the high speed and temperatures generated by atmospheric entry and impact. As the researchers found, such comets are only likely to occur in tightly bound systems where planets orbit closely to each other. Their results show that these systems would be a good place to look for evidence of life (biosignatures) beyond the Solar System.

November 18, 2023November 18, 2023 by Brian Koberlein

The Universe Can't Hide Behind the Zone of Avoidance Any Longer

The central region of the Milky Way, also known as the Zone of Avoidance. Credit: ESO/S. Brunier

Our view of the cosmos is always limited by the fact we are located within a galaxy filled with interstellar gas and dust. This is most dramatically seen in the central region of the Milky Way, which is filled with so much dust that it is sometimes referred to as the Zone of Avoidance. Within this zone, our observations of extragalactic objects are limited, but that is starting to change.

November 17, 2023November 17, 2023 by Evan Gough

ALMA Takes Next-Level Images of a Protoplanetary Disk

This ALMA image of the young star HL Tauri shows rings of dust surrounding the star. The line patterns show the orientation of polarized light. It's the deepest dust polarization image of any protoplanetary disk captured thus far, revealing details about the dust grains in the disk. Credit: NSF/AUI/NRAO/B. Saxton/Stephens et al.

The ESO’s Atacama Large Millimeter/submillimeter Array (ALMA) is perched high in the Chilean Andes. ALMA is made of 66 high-precision antennae that all work together to observe light just between radio and infrared. Its specialty is cold objects, and in recent years, it has taken some stunning and scientifically illuminating images of protoplanetary disks and the planets forming in them.

But its newest image supersedes them all.

November 17, 2023November 17, 2023 by Evan Gough

We’re Entering a New Age When Spacecraft Communicate With Lasers

This artist's illustration shows NASA's Psyche spacecraft approaching the asteroid of the same name. Image Credit: Maxar/ASU/P. Rubin/NASA/JPL-Caltech

In October 2023, NASA launched its long-awaited on-again, off-again Psyche mission. The spacecraft is on its way to study the metal-rich asteroid 16-Psyche, an M-type asteroid that could be the remnant core of a planetesimal that suffered a collision long ago. But understanding the giant, metal-rich asteroid isn’t the Psyche mission’s only goal.

It’s also testing a new laser communication technology.

November 17, 2023November 17, 2023 by Matt Williams

Martian Green Nightglow Seen for the First Time

Artist's impression of the ExoMars Trace Gas orbiter spotting daylight green oxygen at Mars. Credit: ESA

On Earth, there is a phenomenon known as nightglow, where the atmosphere experiences faint light emissions that prevent the night sky from becoming completely dark. This is caused by various processes in the upper atmosphere, like the recombination of atoms, cosmic rays striking the atmosphere, or oxygen and nitrogen interacting with hydroxyl a few hundred kilometers from the surface. Thanks to data obtained by the ESA’s ExoMars Trace Gas Orbiter (TGO), the same phenomenon has been observed in the Martian atmosphere for the first time.

While scientists have long suspected that Mars also experiences this atmospheric phenomenon, this is the first time that effectively proves it. The revelation was made by an international team of scientists based on their analysis of data from the TGO’s Nadir and Occultation for MArs Discovery (NOMAD) spectrometer. When astronauts and rovers explore Mars’ polar regions in the near future, they will see a green glow whenever they look up at the sky and could even use the glow to navigate and find their way in the dark of night.

November 17, 2023November 17, 2023 by Evan Gough

Can a Dead Star Keep Exploding?

This is an artist’s representation of AT2022tsd, an explosion in a distant galaxy. The image shows one possible explanation for the strange object. It could be a black hole accreting matter from a disk and powering a jet. Variation in the jet's direction could produce the observed rapid flashes. Image Credit: Robert L. Hurt/Caltech/IPAC

In September 2022, an automated sky survey detected what seemed to be a supernova explosion about one billion light-years away. The Zwicky Transient Facility (ZTF) spotted it and gave it the name AT2022tsd. But something was different about this supernova. Supernovae explode and shine brightly for months, while AT2022tsd exploded brightly and then faded within days.

November 16, 2023November 16, 2023 by Evan Gough

Hubble Succeeds Where TESS Couldn’t: It Measured the Nearest Transiting Earth-Sized Planet

This is an artist’s concept of the nearby exoplanet, LTT 1445Ac, which is a nearby Earth-size world. The planet orbits a red dwarf star. The star is in a triple system, with two closely orbiting red dwarfs seen at upper right. The black dot in front of the foreground star is planet LTT 1445Ab, transiting the face of the star. Image Credit: NASA, ESA, L. Hustak (STScI)

Twenty-two light-years away, a rocky world orbits a red dwarf. It’s called LTT 1445Ac, and NASA’s Transiting Exoplanet Survey Satellite (TESS) found it in 2022. However, TESS was unable to gauge the small planet’s size.

That’s okay. The venerable Hubble took care of it.

November 16, 2023November 16, 2023 by Mark Thompson

An Asteroid Will Occult Betelgeuse on December 12th

Image of Betelgeuse and graphic showing its location — Image of Betelgeuse (Credit NASA/ESA)

I cannot for the life of me remember when it was or what it was but a fair few years ago I remember positioning a telescope to observe an asteroid as it silently and perhaps slightly eerily drifted between us and the Moon. I say eerily as this asteroid had the ability to cause widespread damage had it hit but of course we knew it posed no threat. I remember at the time thinking it was mind blowing that even today, we still use mathematics with roots (pardon the pun) centuries old to calculate the position of objects in our Solar System. We get to see evidence of this again on 12th December when something rare happens!

November 16, 2023November 16, 2023 by Evan Gough

Take a Plunge Into the Ice Giants

The unique atmospheric compositions of ‘ice giant’ planets Uranus and Neptune were recreated to simulate a plunge deep within them. These simulations are part of preparation for eventual atmospheric probes the ESA intends to send. Image Credit: University of Stuttgart’s High Enthalpy Flow Diagnostics Group

Our Solar System’s ice giants, Uranus and Neptune, have been largely left out of the planetary probe game. While all of the other planets—including even the demoted Pluto—have been the subjects of dedicated missions, the ice giants have not. In fact, the only spacecraft to ever even fly by Uranus and Neptune was Voyager 2 in the late 1980s.

November 16, 2023November 16, 2023 by Evan Gough

JWST Follows Neon Signs Toward New Thinking on Planet Formation

This artist's illustration shows the young star SZ Chamaeleontis (SZ Cha). SZ Cha is surrounded by a protoplanetary disk of gas and dust. Planets may form in the disk, but they're running out of time. Image Credit: NASA, ESA, CSA, Ralf Crawford (STScI)

Everyone knows that the James Webb Space Telescope is a ground-breaking infrared space telescope that’s helping us better understand the cosmos. The JWST’s discerning infrared eyes are deepening our understanding of everything from exoplanets to primitive galaxies to the birth of stars.

But it’s not the first ground-breaking infrared space telescope we’ve launched. There was IRAS, then ISO, then the Spitzer Space Telescope. The Spitzer is the JWST’s most recent infrared predecessor, and the JWST is observing one of the same targets that the Spitzer did, taking note of some puzzling changes.