Space News & Blog Articles

On Feb. 18th, 2021, NASA’s Perseverance rover landed within the Jezero Crater on Mars. Like its predecessor, Curiosity, a fellow member of NASA’s Mars Exploration Program (MEP), the goal of Perseverance is to seek out evidence of possible life on Mars (past and present). A key part of this mission will be the first sample return ever performed on Mars, where samples obtained by Perseverance will be placed in a cache for later retrieval and return to Earth.

For the past five months, mission controllers at NASA have been driving the rover further from where it landed (Octavia E. Butler Landing Site) and conducting test flights with the Ingenuity helicopter. NASA is now in the midst of making final preparations for Perseverance to collect its first sample of Martian rock. This historic first is expected to begin by the end of the month or by early August and will culminate with the return of the samples to Earth by 2031.

This rock will come from an area known as the “Cratered Floor Fractured Rough,” a 4 km2 (1.5-square-mile) patch of crater floor that may contain Jezero’s deepest and most ancient layers of exposed bedrock. These rocks will also be the most significant sample return since the Apollo astronauts brought rocks back from the Moon. These samples are still teaching us things about the formation of the Earth-Moon System and the evolution of the Solar System.

Still from the interactive map showing the location of the Perseverance rover and Ingenuity helicopter. Credit: NASA/JPL-Caltech

Said Thomas Zurbuchen, associate administrator for science at NASA Headquarters, in a recent NASA press release:

“When Neil Armstrong took the first sample from the Sea of Tranquility 52 years ago, he began a process that would rewrite what humanity knew about the Moon. I have every expectation that Perseverance’s first sample from Jezero Crater, and those that come after, will do the same for Mars. We are on the threshold of a new era of planetary science and discovery.”

The Earth’s magnetic field is an underappreciated wonder of the natural world.  It protects our atmosphere, provides some of the most breathtaking scenery when it creates auroras, and allows people to navigate from one side of the world to the other.  Unfortunately, it won’t be able to save us from the death of the Sun though.  At least that’s the finding of some new research by Dr. Dimitri Veras of the University of Warwick and Dr. Aline Vidotto of Trinity College Dublin.

The Sun’s expected life cycle is pretty well mapped out by scientists. After it’s current main sequence phase is over, it will run out of the hydrogen fuel source that powers the nuclear fusion in its core.  Without the pushing force of the fusion, the Sun itself will contract and then heat up.  That additional heat will push its outer atmosphere to many multiples of its size today, potentially even swallowing up Earth, but definitely consuming Venus and Mercury.  

UT video discussing the end state of the sun.

During its red giant phase, the sun will also create a powerful, fluctuating solar wind.  Usually our magnetic field is able to stop the particles of the solar wind from stripping away Earth’s atmosphere.  However, with the increased amount of particles caused by the red giant constantly bombarding it, the magnetic field has little chance of protecting its atmosphere.  As it is stripped away, the probability of life surviving on the planet slowly diminishes, despite the fact that the Earth will likely be pulling farther away from the Sun due to the decrease in gravity associated with the star’s lower mass.

The habitable zone around red giants is much farther out than main sequence yellow stars – putting it out past the orbit of Neptune.  The slow orbital path Earth will be taking won’t get us there in time before all life on the planet’s surface is cooked.  So we can be sure that a dying sun would likely be able to kill us in more than one way.

UT video on how to stave off the destructive red giant phase of the Sun’s lifecycle.

After its red giant phase, though, a white dwarf emerges, which is much more stable and doesn’t emit any solar wind at all.  But in order for life to survive to this point, its planet’s magnetic sphere has to be approximately 100 times the strength of Jupiter’s, and it has to be able to move quickly between the habitable zones of three different star types.

As of July 23, 2021, China’s Mars rover Zhurong has traveled 585 meters across the surface of Mars. And along the way, it’s taking pictures of interesting sights.

Some of the most intriguing recent images from the rover show debris from the rover’s landing. During its drives, the rover came upon the parachute and backshell. The China National Space Administration says as the rover drove south of its landing site, it first “saw” the debris on the horizon with its front obstacle avoidance camera, and then took a closer image (lead image) with its navigation terrain camera.

CNSA said the rover was about 30 meters away from the parachute and backshell assembly in this image, and about 350 meters away from the landing site.

Zhruong’s front obstacle avoidance camera took this image of the backshell in the distance. Credit: CNSA.

July 23 marked the first anniversary of the launch of the Tianwen-1 and Zhurong rover mission. The lander carrying the rover touched down on Mars on May 15 of this year, landing in the southern part of Utopia Planitia, a vast plain in the northern hemisphere of Mars.

Here are more images from Zhurong:

Gravitational-wave astronomy is set to revolutionize our understanding of the cosmos. In only a few years it has significantly enhanced our understanding of black holes, but it is still a scientific field in its youth. That means there are still serious limitations to what can be observed.

Currently, all gravitational observatories are based on Earth. This makes the detectors easier to build and maintain, but it also means the observatories are plagued by background noise. Observatories such as LIGO and Virgo work by measuring the distance shift between mirrors as a gravitational wave passes through the observatory. This shift is extremely small. For mirrors placed 4 kilometers apart, the shift is a mere fraction of the width of a proton. The vibrations of a truck driving down a nearby road will shift the mirrors much more than that. So LIGO and Virgo use statistics and models of black hole mergers to distinguish a true signal from a false one.

Theoretical observation range for GLOC. Credit: Jani, et al

Because of terrestrial background noise, current observatories focus on the high-frequency gravitational waves (10 – 1000 Hz) generated by black hole mergers. There has been discussion of building a space-based gravitational-wave observatory, such as LISA, which would observe low-frequency gravitational waves, such as those generated by early cosmic inflation. But many gravitational waves are in the intermediate range. To detect these, a recent study proposes building a gravitational-wave observatory on the Moon.

The Moon has long been a coveted location for astronomers. Optical telescopes on the Moon wouldn’t suffer from atmospheric blurring, and unlike space-based telescopes such as Hubble and Webb, they wouldn’t be limited by the size of your launch rocket. Most of the ideas proposed have been very hypothetical, but as we look towards a human return to the Moon in the next decade they are becoming less so. Already NASA is studying the construction of a radio telescope on the far lunar surface. Building a lunar gravitational-wave observatory would be significantly more challenging, but not impossible.

This recent study proposes a Gravitational-wave Lunar Observatory for Cosmology (GLOC). Rather than worrying about how such an observatory would be constructed, the study instead focuses on the sensitivity and observational limits of such an observatory. As you might expect, a lunar observatory wouldn’t suffer from the background vibrations that trouble Earth observatories. As a result, it could have a baseline four times longer than LIGO. This would give it a range on gravitational wave frequencies as low as a tenth of a Hertz. This would allow it to observe everything from stellar-mass binary mergers to those of intermediate-mass black holes.

Planetary formation is a complicated, multilayered process.  Even with the influx of data on exoplanets, there are still only two known planets that are not yet fully formed.  Known as PDS 70b and PDS 70c, the two planets, which were originally found by the Very Large Telescope, are some of the best objects we have to flesh out our planetary formation models. And now, one of them has been confirmed to have a moon-forming disk around it.

That additional insight came from observations conducted by ALMA.  Astronomers had long predicted that planet PDS 70c was surrounded by such a disk, but with the images they had captured previously they were unable to confirm its existence.  Now, it has been physically confirmed beyond the shadow of a doubt.

UT video discussing the formation of our own moon.

Moon formation is even less well understood than planetary formation at this point.  Even the origins of our own Moon are still up for debate.  But the PDS 70c discovery has the potential to illuminate the creation of at least one as we are watching.  In fact, there is enough material in the disk to create three moons the size of our own around the Jupiter-like planet.  

The moon formation process also plays a key part in planetary formation, with circumplanetary disks that can form moons also influencing the creation of the planet itself.  Watching that disk evolve will help scientists with their models of both moon and planetary formation.  

UT video discussing exomoons with Dr. David Kipping

That evolution is sure to take millions of years, but so far PDS 70c is the only known planet with any type of circumplanetary disk.  The same data set confirming its existence showed that it’s Saturn-like twin, PDS 70b, does not have a disk that some scientists had previously suggested.  Others might be found with more powerful telescopes, but until then this system is the best we have.

Observing the dark side of planets is hard. In the visible spectrum, they are almost unobservable, while in the infrared some heat signatures may come through, but not enough to help see what is going on in a planet’s atmosphere.  Now a team from the University of Tokyo think they’ve developed a way to monitor weather patterns on the night side of one of the most difficult planets of all – Venus.

Venus is well known for its turbulent atmosphere and hellish temperatures.  But on the night side of the planet it is not clear what effect the cooling associated with being out of the sun has on the “weather” of the planet.  Venus’ weather itself can be thought of as the continual movement of clouds in the dense planetary atmosphere.  But on the night side, the resolution of infrared images that might be able to provide insight into that weather hasn’t been high enough to be useful.

UT discussion of the formation of Venus.

So Professor Takeshi Imamura from the University of Tokyo turned to Venus Climate Orbiter Akatsuki.  It is the first ever Japanese probe to orbit another planet, and has been providing images of Venus’ atmosphere since shortly after its launch in 2010.  In that time, it has managed to collect some data on the night side of the planet, but trying to resolve small cloud patterns against the overall background of noise in the nighttime Venusian atmosphere proved difficult.  

Adding to that difficulty were fierce winds that whip the atmosphere around at speeds exceeding hurricane-force winds on Earth.  Known as a “super-rotation”, this phenomenon is specific to the atmosphere of Venus.  Forcing weather patterns rapidly from east to west, it makes tracking those weather patterns particularly difficult.  But not too difficult for graduate student Kiichi Fukuya.  He developed a methodology that allows researchers to account for the super-rotation in their data, and isolate small scale cloud movements that lie therein.

Directional lines of wind action on the different sides of Venus.
Credit – JAXA / Imamura et al.

One dramatic outcome from the newfound ability to correct for the super-rotation is finding that the north-south winds that drive some of the atmosphere’s circulation switch direction on the night side of the planet.  The full consequences of such an abrupt change are sure to be huge, but Dr. Imamura and his team have not yet parsed them out.