Universe Today

August 26, 2020August 26, 2020 by Nancy Atkinson

It Rained So Hard on Ancient Mars that Craters Filled Up and Overflowed

Arima twins topography. This colour-coded overhead view is based on an ESA Mars Express High-Resolution Stereo Camera digital terrain model of the Thaumasia Planum region on Mars at approximately 17°S / 296°E. The image was taken during orbit 11467 on 4 January 2013. The colour coding reveals the relative depth of the craters, in particular the depths of their central pits, with the left-hand crater penetrating deeper than the right (Arima crater). Copyright: ESA/DLR/FU-Berlin-G.Neukum

Figuring out the ancient climate on Mars has been tricky. While evidence gathered from orbit and on the surface seems to indicate there must have been a lot more water on Mars early in its history, questions remain on how much water and in what form.

A new study has now quantified the amount of precipitation needed to create many of the landforms visible today on Mars surface. The paper, published in the journal Geology says there was enough rainfall and snowmelt to fill lakebeds and river valleys 3.5 to 4 billion years ago on the Red Planet, and that precip must have occurred worldwide.

August 26, 2020August 26, 2020 by Matthew Cimone

There’s No Chemical Difference Between Stars With or Without Planets

Orion Nebula - Closest Star Forming Region to Earth c Cimone - Trottier Observatory

Strange New Worlds

Imagine if a star could tell you it had planets. That would be really helpful because finding planets orbiting distant stars – exoplanets – is hard. We found Neptune, the most distant planet in our own solar system, in 1846. But we didn’t have direct evidence of a planet around ANOTHER star until….1995.…149 years later. Think about that. Any science fiction you watched or read that was written before 1995 which depicted travel to exoplanets assumed that other planets even existed. Star Trek: The Next Generation aired its last season in 1994. We didn’t even know if Vulcan was out there. (Now we do!…sortof)

Jupiter (right bright point) and Saturn (left bright point) seen here against the Milky Way were the most distant planets we could see before inventing telescopes – C. Matthew Cimone

August 25, 2020August 26, 2020 by Matt Williams

We Have the Technology to Retrieve a Sample From an Interstellar Object Like Oumuamua

Artist’s impression of the interstellar object, `Oumuamua, experiencing outgassing as it leaves our Solar System. Credit: ESA/Hubble, NASA, ESO, M. Kornmesser

On October 19th, 2017, astronomers were astounded to learn that an interstellar object (named ‘Oumuamua) flew by Earth on its way out of the Solar System. Years later, astronomers are still debating what this object was – a comet fragment, a hydrogen iceberg, or an extraterrestrial solar sail? What’s more, the arrival of 2I/Borisov two years later showed how interstellar objects (ISOs) regularly enter our Solar System (some even stay!)

It’s little wonder then why proposals are in place to design missions that could rendezvous with an interstellar object the next time one passes by. One such mission is Project Lyra, a concept proposed by researchers from the Initiative for Interstellar Studies (i4is). Recently, an international team led from the I4IS drafted a White Paper that was submitted to the 2023-2032 Planetary Science and Astrobiology Decadal Survey.

August 25, 2020August 25, 2020 by Nancy Atkinson

Everyone Took Pictures of Comet NEOWISE, Including Hubble

This ground-based image of comet C/2020 F3 (NEOWISE) was taken from the Northern Hemisphere on July 16, 2020. The inset image, taken by the Hubble Space Telescope on Aug. 8, 2020, reveals a close-up of the comet after its pass by the Sun. Hubble’s image zeroes in on the comet’s nucleus, which is too small to be seen. It’s estimated to measure no more than 3 miles (4.8 kilometers) across. Instead, the image shows a portion of the comet’s coma, the fuzzy glow, which measures about 11,000 miles (18,000 kilometers) across in this image. Comet NEOWISE won’t pass through the inner solar system for another nearly 7,000 years. Credits: NASA, ESA, STScI, Q. Zhang (Caltech); ground-based image copyright © 2020 by Zoltan G. Levay, used with permission.

This summer we were (finally) treated to a spectacular, naked-eye comet, C/2020 F3 NEOWISE. And while seeing it with our own eyes was a joy, it was incredible to see the varied photos of NEOWISE taken by people around the world, showing the comet’s long gossamer tails, filled with detail and color. (See our gallery of images here.)

Now, the Hubble Space Telescope has released a high-resolution image of NEOWISE. However, it might not be the view you may have expected.

August 24, 2020August 24, 2020 by Brian Koberlein

Scientists Recreate the Density of a White Dwarf in the Lab

Illustration of the internal layers of a white dwarf star. Credit: University of Warwick/Mark Garlick

The density of a white dwarf star defies our imagination. A spoonful of white dwarf matter would weigh as much as a car on Earth. Atoms within the star are squeezed so tightly that they are on the edge of collapse. Squeeze a white dwarf just a bit more, and it will collapse into a neutron star. And now, we can recreate the density of a white dwarf within a lab.

August 24, 2020August 24, 2020 by Nancy Atkinson

Completely Harmless Asteroid Almost Certainly Won’t Hit Earth Just Before the US Election

A long-trailed, earthgrazing Eta Aquarid meteor I saw on May 6, 2013. Credit: Bob King

In a year of devastating wildfires, destructive derechos, early and active hurricanes, widespread social unrest, contentious politics and more — all amid an unprecedented global pandemic — it might seem fitting that ‘asteroid impact’ would be added to the 2020 bingo card.

August 23, 2020August 23, 2020 by Andy Tomaswick

Did Jupiter Push Venus Into a Runaway Greenhouse?

Venus has been garnering a lot of attention lately, though primarily in the scientific community as the last Hollywood movie about the planet was released in the 1960s. This is in part due to its dramatic difference from Earth, and what that difference might mean for the study of exoplanets. If we can better understand what happened during Venus’ formation to make it the hell scape it is today, we might be able to better understand what truly constitutes the habitable zone around other stars.

Numerous planetary scientists have focused on Venus’ formation and atmospheric development in the recent past. Now a new paper posits that Venus might have had liquid water on its surface as recently as one billion years ago. And a contributor to the disappearance of that water might be an unlikely culprit: Jupiter.

August 22, 2020February 7, 2022 by Matt Williams

Beyond “Fermi’s Paradox” VI: What is the Berserker Hypothesis?

Welcome back to our Fermi Paradox series, where we take a look at possible resolutions to Enrico Fermi’s famous question, “Where Is Everybody?” Today, we examine the possibility that the reason for the Great Silence is that all the aliens are dead!

In 1950, Italian-American physicist Enrico Fermi sat down to lunch with some of his colleagues at the Los Alamos National Laboratory, where he had worked five years prior as part of the Manhattan Project. According to various accounts, the conversation turned to aliens and the recent spate of UFOs. Into this, Fermi issued a statement that would go down in the annals of history: “Where is everybody?“

This became the basis of the Fermi Paradox, which refers to the disparity between high probability estimates for the existence of extraterrestrial intelligence (ETI) and the apparent lack of evidence. Since Fermi’s time, there have been several proposed resolutions to his question, which includes the Berserker Hypothesis. This theory suggests we haven’t heard from any alien civilizations because they’ve been wiped out by killer robots!

August 21, 2020August 21, 2020 by Matt Williams

Lunar Landings Will Make it Harder to Study the Moon’s Ice Deposits

Artist's impression of surface operations on the Moon. Credit: NASA

When astronauts return to the Moon in the next few years (as part of Project Artemis) they will be scouting locations and resources around the South Pole-Aitken Basin that will eventually help them to stay there. In this cratered, permanently-shadowed region, water ice has been found in abundance, which could one-day be harvested for drinking water, irrigation, and the creation of oxygen gas and rocket fuels.

A critical aspect to planning for all or this is to consider how future missions may affect the local environment. Based on new research from a team of planetary scientists and engineers, a major risk comes in the form of contamination by lunar landers. In short, exhaust from these vehicles could spread around the Moon and contaminate the very ices the astronauts hope to study.

August 21, 2020August 21, 2020 by Nancy Atkinson

Could There Be Life in the Cloudtops of Venus?

A composite image of the planet Venus as seen by the Japanese probe Akatsuki. The clouds of Venus could have environmental conditions conducive to microbial life. Credit: JAXA/Institute of Space and Astronautical Science

When it comes to places with the potential for habitability, Venus isn’t usually considered on that list. The hot, greenhouse-effect-gone-mad neighboring planet with a crushing surface pressure and sulfuric acid clouds certainly isn’t friendly to life as we know it, and the few spacecraft humanity has sent to Venus’ surface have only endured a few minutes.

But up about 40 to 60 km (25 to 37 miles) above the surface, the atmosphere of Venus is the most Earth-like of any other place in the Solar System. There, Venus has air pressure of approximately 1 bar and temperatures in the 0°C to 50°C range. It’s not quite a shirtsleeves environment, as humans would need air to breathe and protection from the sulfuric acid in the atmosphere. Plus, also consider that Venus is considered to be in the habitable zone of our star.