Space News & Blog Articles

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.

The research team included astronomers from the Center for Space Physics (CSP) at Boston University, the Division of Geological and Planetary Sciences (GPS) at Caltech, the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado, Earth and Planetary Science at the UC Berkeley, Large Binocular Telescope Observatory (LBT), the Southwest Research Institute (SwRI), the Planetary Science Institute (PSI), the Leibniz-Institute for Astrophysics Potsdam (AIP), and NASA’s Goddard Space Flight Center. The two studies, titled “The Optical Aurorae of Europa, Ganymede, and Callisto” and “Io’s Optical Aurorae in Jupiter’s Shadow,” appeared on February 16th in the Planetary Science Journal.

Galilean Family Portrait. Credit: NASA/JPL

The team’s observations combined data from the Keck Observatory’s High-Resolution Echelle Spectrometer (HIRES) with high-resolution spectra from the Large Binocular Telescope (LBT) and the Apache Point Observatory (APO). These observations were timed to see Io, Europa, Ganymede, and Callisto when they entered Jupiter’s shadow to avoid interference from sunlight reflected off their surfaces. This data revealed valuable information concerning the composition of the moons’ atmospheres, which included oxygen gas (as expected).

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?

That’s the question researchers asked themselves for years as they tried to figure out how heavy elements like manganese, iron, and plutonium showed up on Earth. It turns out they’re made in different processes, often in different parts of the Milky Way. Yet, they’ve been found layered together on Earth’s seabed. That implies they arrived about the same time, despite their different origins.

Scientists from the University of Hertfordshire in the UK and the Konkoly Observatory, Research Centre for Astronomy and Earth Sciences in Hungary put together some theories and computer models to simulate how elements travel through space. The answer they came up with: the elements from faraway events are carried by supernova shock fronts just like surfers catching a wave.

Heavy Elements: From Nucleosynthesis to Deep-sea Mining

To understand how stuff from distant conflagrations ended up on Earth, it’s worth taking a quick look at those events. First, there are the Type II supernovae. They occur when a supermassive star dies. That’s one at least eight times the mass of the Sun. These stars fuse heavier and heavier elements (such as carbon) in their cores. When they get to creating iron, they don’t have enough energy to keep up the production line. The cores collapse and then everything expands outward very rapidly in a supernova explosion. That’s enough to send its heavy elements racing through space.

SN 1987A, an example of a Type II-P supernova. This likely created heavier elements such as iron and others. Credit: NASA

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.

During the timelapse, you can see various rocks that Perseverance stopped to study with its robotic arm and sensors. The rover has now traveled almost 15 km (9 miles). In addition to studying numerous rocks, it has also collected and stowed away 18 sample containers of rocks, regolith, and even the Martian atmosphere, to be gathered later and brought to Earth in a future Mars Sample Return mission.

“Anniversaries are a time of reflection and celebration, and the Perseverance team is doing a lot of both,” said Perseverance project scientist Ken Farley of Caltech in Pasadena, in a press release. “Perseverance has inspected and performed data collection on hundreds of intriguing geologic features, collected 15 rock cores, and created the first sample depot on another world. With the start of the next science campaign, known as ‘Upper Fan,’ on Feb. 15, we expect to be adding to that tally very soon.”

NASA put together a huge list of rover highlights from the first two years.

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.

“In this article, we show that the probability of capturing large trans-Neptunian objects (TNOs) by Planet Nine to form a satellite system in the scattered disk region (between the inner Oort Cloud and Kuiper Belt) is large,” wrote astronomer Man Ho Chan of The Education University of Hong Kong, in his paper, published as a preprint on arXiv. “By adopting a benchmark model of Planet Nine, we show that the tidal effect can heat up the satellites significantly, which can give sufficient thermal radio flux for observations.”

Out beyond the orbit of Neptune, a cluster of Kuiper Belt Objects (KBOs) exhibit strange inclinations in their orbits, as they all line up in a single direction and tilt nearly identically away from the plane of the Solar System. Additionally, the orbit of 90377 Sedna can’t be explained by the presence of Neptune alone. That’s the where the hypothesis of Planet Nine comes in, where a potential super-Earth, about 5-10 times the mass of Earth could be lurking in the outer solar system, as yet undetected.

Since the theoretical 9th planet has yet to be found, other researchers have put forth other explanations besides a large planet, such as a disc of icy material, or another study suggested the collective mass of the KBOs themselves was responsible.

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.

Here’s a video about the Enterprise Flight, created before the mission was rescheduled from 2022 to 2023:

“Our Enterprise Flight is an historic mission by any standard,” Celestis co-founder and CEO Charles M. Chafer said today in a news release. “The overarching goal of Celestis is to assist human expansion throughout the solar system. By adding the DNA of these American icons to Enterprise, we establish a precursor for future human missions, and add to the historical record of human exploration of deep space.”