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The first palaeontologist on Mars

(Image: Artist’s impression of NASA’s Perseverance rover on Mars)

Today NASA’s Perseverance rover landed on Mars. I don’t usually talk astronomy on this blog, but this time it’s relevant because—as you might have read—Perseverance is more or less the first palaeontologist on Mars!

Let me explain.

(Image: Satellite topography map of Jezero Crater, the site where Perseverance landed)

The site where Perseverance is landing, Jezero Crater, is a meteor impact crater near Mars’s Equator (say that 10 times fast!). It has evidence of a delta—the geomorphic feature that occurs when running water enters a large body of water. Orbital analyses also suggest it’s filled with carbonate rock—the kind that tend to deposit at the bottom of bodies of water.

Jezero Crater is not filled with water today. But the evidence strongly suggests it once was. If we’re going to find evidence of life on Mars, this is a good place to start looking.

Microbial fossils

When you think of fossils, most people think of giant T. rex skeletons, or frozen woolly mammoths, or neanderthal skulls. Maybe you’ve been around the block a bit, and you think about corals, or plant fossils, or tiny fossil shells. But some of the most common and important fossils on Earth are even tinier. Microbial fossils are commonly made by bacteria, archaea, and the like.

(Image: A cross-section of a stromatolite fossil, showing the multiple layers)

Some of the earliest fossils on earth are called stromatolites. They occur when bacterial colonies grow together in a mat—then, over time, sediment deposits over the colony, and the bacteria form another layer on top of the previous layer. Over time, many layers can be formed.

(Image: Helium Ion Microscopy image of iron oxide filaments formed by bacteria)

Although we breathe in oxygen and breathe out carbon dioxide, many microbes are not quite so restricted, and can breathe anything from sulphur to iron to methane or ammonia. When they do this, they often leave behind solid waste products, such as the above iron oxide filaments, that give away their presence. We can tell these apart from normal minerals in a number of ways, including by the relative proportions of different isotopes in them.

(Image: Schematic digram showing how molecular fossils form and are studied)

However, some of the most important fossils are molecular fossils. Living organisms produce a variety of different organic molecules; even long after the bodies of these organisms decay, those molecules can stay behind in an altered form for millions or even billions of years. If we’re looking for evidence of life on Mars, this might be our best bet.

Enter Perseverance

(Image: Diagram of Perseverance rover showing different instruments)

The Perseverance rover is overall similar in design to the Curiosity rover that landed in 2012, but there are some key differences—and most relevant here is that it’s a geological powerhouse. It’s got a number of instruments designed to carry out detailed geologic investigations:

RIMFAX is a ground-penetrating Radar unit. Like normal Radar, it works by sending radio waves into the ground; different materials affect the radio waves differently, as do transitions between different materials. This will allow us to, for the first time, study the geology of Mars below the surface to get an idea of what has been going on down there.

(Image: This is the kind of result produced by ground-penetrating radar—a rough image of the stratigraphy below the surface.)

PIXL (Planetary Instrument for X-ray Lithochemistry) shoots x-rays at samples and examines how they fluoresce in reaction. This allows for the detection of the elemental composition of a sample—helping us better understand the geology of the area, and potentially detect signatures of life. 

SuperCam is a multi-function laser spectrometer that uses four different spectroscopy methods to examine the composition of samples. They all work in similar ways—essentially, different molecules react to laser stimulation differently, and different amounts of energy are required to make different molecules vibrate. The way that these molecules react can help us identify their composition, and the hope is that this may allow us to detect molecular fossils (these methods allow us to detect molecular fossils on Earth!)

SHERLOC (Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals) is another spectroscopic instrument—this one, however, is more precise, and optimised for detecting trace biosignatures in samples. It works similar to the above, using an ultraviolet laser to scan a 7 × 7 mm zone for evidence of organic compounds. 

In addition to studying samples in situ, Perseverance will package small samples and leave them behind on Mars. A planned future mission will collect these packaged samples and launch them into space, where an orbiter will collect them and—hopefully—return them to Earth. This would be the first time that samples have ever been recovered from Mars, and would go a long way in increasing our understanding of the Martian environment and geology.

There’s no way of knowing yet what Perseverance will find—but even the fact that a robot palaeontologist is on Mars is incredibly exciting. Here’s to many years of discovery!

Update your phones with our #CountdownToMars wallpapers, like this one, today: https://www.nasa.gov/feature/perseverance-mars-rover-wallpaper-images/

It's LANDING DAY for our Perseverance Mars Rover and her mission to search for ancient signs of life on the Red Planet!

Watch LIVE coverage today starting at 2:15pm ET (18:15 UTC):

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Jupiter Descending 

what is your favorite natural satellite?

Orion Capsule interior. 🚀

Amazing Space Shuttle Shot. 🚀

Discovery Shuttle docked to the ISS. 🌎🚀

Shuttle Atlantis crew shot. 👨🏻‍🚀👩🏻‍🚀🚀

Shuttle Endeavour’s flight deck. 🚀

Mercury capsule interior. 🚀

Grid fin hydraulic pump stalled, causing a soft water landing 🚀 POV shot.

Still most likely being reused in a CRS mission 🤘🏻

After completing its SSO-A mission of launching a record breaking 64 satellites at once, the B5 Falcon 9 booster landed for the third time breaking another record!

Space Shuttle launch. 🌎🚀

Shuttle Atlantis over the Bahamas. 🚀

Earth images photographed by satellites and the International Space Station

images

Should NASA Send New Horizons To A Nearby Star For Its Final Mission?

“Over the next million years, the Voyagers and Pioneers will approach numerous stars, but only at relatively large separations. The closest will be Pioneer 10, encountering HIP 1177795 in ~90,000 years from 0.75 light-years away. But New Horizons, unlike the others, still has significant fuel remaining. After encountering Pluto and Arrokoth, it may yet target another object in the outer Kuiper belt. Subsequently, it will eventually enter interstellar space, but can be boosted to approach future stellar targets.”

In the 1970s, four spacecraft were launched with speeds large enough that they would eventually escape the Solar System: Pioneer 10 and 11 and Voyager 1 and 2. In the 2000s, New Horizons became the fifth spacecraft that will leave the Solar System and enter interstellar space. But unlike the other four, it still has fuel remaining and could boost itself to alter its trajectory. In the aftermath of the ESA’s Gaia mission, we now can predict where more than a billion stars in the Milky Way will be located up to a million years in the future, raising the possibility that we could alter New Horizon’s trajectory to encounter another solar system in the distant future.

Should we do it? Of course we should! Come learn about this fascinating possibility today.

What Separates A Good Scientific Theory From A Bad One?

“It’s why an idea like dark matter is so powerful. By adding just a single new species of particle — something that’s cold, collisionless, and transparent to light and normal matter — you can explain everything from rotating galaxies to the cosmic web, the fluctuations in the microwave background, galaxy correlations, colliding galaxy clusters, and much, much more. It’s why ideas with a huge number of free parameters that must be tuned to get the right results are less satisfying and less predictively powerful. If we can model dark energy, for instance, with just one constant, why would we invent multi-field models with many parameters that are no more successful?”

You’ve often heard, when discussing competing scientific ideas, of appealing to Occam’s razor. Often paraphrased as “all things being equal, the simplest explanation is usually best,” it seems to open the door for people to argue over which explanation is simplest. This should not, however, be a point of contention: the explanation that’s simplest is the one that introduces the fewest number of new, additional free parameters. And when it comes to all things being equal, the things in question ought to be the number of new phenomena the novel idea can explain, along with the number of discernible predictions as compared with the old, prevailing idea. The best scientific ideas are the ones that explain the most by adding the least, while the worst ones unnecessarily add additional parameters on top of what we observe for no good reason other than personal bias. Ideas may be a dime-a-dozen, but a good idea is hard to find.

The next time you encounter an interesting, wild idea that someone throws out there, use this criteria to evaluate it. You just might be surprised at how quickly you can tell whether an idea is good or bad!

Pluto’s Surface Changes Faster Than Earth’s, And A Subsurface Ocean Is Driving It

“These mountains aren’t static and stable, but rather are temporary water-ice mountains atop a volatile, nitrogen sea. The evidence for this comes from multiple independent observations. The mountains only appear between the hilly highlands, after the edge of a basin rim, and young plains with flowing canals. These young plains occur in Pluto’s heart-shaped lobe, which itself was caused by an enormous impact crater. Only a subsurface, liquid water ocean beneath the crust could cause the uplift we then see, leaving the nitrogen to fill it in.”

In July of 2015, NASA’s New Horizons Mission arrived at Pluto, photographing the world at the highest resolution ever, with some places getting as up-close as just 80 meters (260 feet) per pixel. Not bad for a world more than 3 billion miles (5 billion kilometers) from home! What we’ve learned is breathtaking. Rather than a static, frozen world, we found one with tons of evidence for active, interior geology, as well as with a changing surface that renews itself and undergoes cycles, quite unexpectedly to many. There’s also not an enormous heart, but rather a massive, volatile-filled crater that caused Pluto to tip over at least once in its past, and may yet cause it to tip over again in the near future.

If you ever wanted to know how these distant, icy worlds come alive, there’s never been a better way to find out than in the aftermath of what New Horizons taught us!

Charon, moon of Pluto, observed by NASA’s New Horizons probe on this day in 2015.

Pluto as seen from NASA’s New Horizons spacecraft ; Its heart-shaped sea is filled with poisonous ice.

How the New Horizon’s flyby changed the way we see Pluto 💓 [NASA/JPL] 

Solar System 10 Things: Looking Back at Pluto

In July 2015, we saw Pluto up close for the first time and—after three years of intense study—the surprises keep coming. “It’s clear,” says Jeffery Moore, New Horizons’ geology team lead, “Pluto is one of the most amazing and complex objects in our solar system.”

1. An Improving View

These are combined observations of Pluto over the course of several decades. The first frame is a digital zoom-in on Pluto as it appeared upon its discovery by Clyde Tombaugh in 1930. More frames show of Pluto as seen by the Hubble Space Telescope. The final sequence zooms in to a close-up frame of Pluto taken by our New Horizons spacecraft on July 14, 2015.

2. The Heart

Pluto’s surface sports a remarkable range of subtle colors are enhanced in this view to a rainbow of pale blues, yellows, oranges, and deep reds. Many landforms have their own distinct colors, telling a complex geological and climatological story that scientists have only just begun to decode. The image resolves details and colors on scales as small as 0.8 miles (1.3 kilometers). Zoom in on the full resolution image on a larger screen to fully appreciate the complexity of Pluto’s surface features.

3. The Smiles

July 14, 2015: New Horizons team members Cristina Dalle Ore, Alissa Earle and Rick Binzel react to seeing the spacecraft’s last and sharpest image of Pluto before closest approach.

4. Majestic Mountains

Just 15 minutes after its closest approach to Pluto, the New Horizons spacecraft captured this near-sunset view of the rugged, icy mountains and flat ice plains extending to Pluto’s horizon. The backlighting highlights more than a dozen layers of haze in Pluto’s tenuous atmosphere. The image was taken from a distance of 11,000 miles (18,000 kilometers) to Pluto; the scene is 780 miles (1,250 kilometers) wide.

5. Icy Dunes

Found near the mountains that encircle Pluto’s Sputnik Planitia plain, newly discovered ridges appear to have formed out of particles of methane ice as small as grains of sand, arranged into dunes by wind from the nearby mountains.

6. Glacial Plains

The vast nitrogen ice plains of Pluto’s Sputnik Planitia – the western half of Pluto’s “heart”—continue to give up secrets. Scientists processed images of Sputnik Planitia to bring out intricate, never-before-seen patterns in the surface textures of these glacial plains.

7. Colorful and Violent Charon

High resolution images of Pluto’s largest moon, Charon, show a surprisingly complex and violent history. Scientists expected Charon to be a monotonous, crater-battered world; instead, they found a landscape covered with mountains, canyons, landslides, surface-color variations and more.

8. Ice Volcanoes

One of two potential cryovolcanoes spotted on the surface of Pluto by the New Horizons spacecraft. This feature, known as Wright Mons, was informally named by the New Horizons team in honor of the Wright brothers. At about 90 miles (150 kilometers) across and 2.5 miles (4 kilometers) high, this feature is enormous. If it is in fact an ice volcano, as suspected, it would be the largest such feature discovered in the outer solar system.

9. Blue Rays

Pluto’s receding crescent as seen by New Horizons at a distance of 120,000 miles (200,000 kilometers). Scientists believe the spectacular blue haze is a photochemical smog resulting from the action of sunlight on methane and other molecules in Pluto’s atmosphere. These hydrocarbons accumulate into small haze particles, which scatter blue sunlight—the same process that can make haze appear bluish on Earth.

10. Encore

On Jan. 1, 2019, New Horizons will fly past a small Kuiper Belt Object named MU69 (nicknamed Ultima Thule)—a billion miles (1.5 billion kilometers) beyond Pluto and more than four billion miles (6.5 billion kilometers) from Earth. It will be the most distant encounter of an object in history—so far—and the second time New Horizons has revealed never-before-seen landscapes.

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Io - The Volcanic Moon

Looking like a giant pizza covered with melted cheese and splotches of tomato and ripe olives, Io is the most volcanically active body in the solar system. Volcanic plumes rise 300 km (190 miles) above the surface, with material spewing out at nearly half the required escape velocity.

A bit larger than Earth’s Moon, Io is the third largest of Jupiter’s moons, and the fifth one in distance from the planet.

Although Io always points the same side toward Jupiter in its orbit around the giant planet, the large moons Europa and Ganymede perturb Io’s orbit into an irregularly elliptical one. Thus, in its widely varying distances from Jupiter, Io is subjected to tremendous tidal forces. These forces cause Io’s surface to bulge up and down (or in and out) by as much as 100 m (330 feet)! Compare these tides on Io’s solid surface to the tides on Earth’s oceans. On Earth, in the place where tides are highest, the difference between low and high tides is only 18 m (60 feet), and this is for water, not solid ground!

This tidal pumping generates a tremendous amount of heat within Io, keeping much of its subsurface crust in liquid form seeking any available escape route to the surface to relieve the pressure. Thus, the surface of Io is constantly renewing itself, filling in any impact craters with molten lava lakes and spreading smooth new floodplains of liquid rock. The composition of this material is not yet entirely clear, but theories suggest that it is largely molten sulfur and its compounds (which would account for the varigated coloring) or silicate rock (which would better account for the apparent temperatures, which may be too hot to be sulfur). Sulfur dioxide is the primary constituent of a thin atmosphere on Io. It has no water to speak of, unlike the other, colder Galilean moons. Data from the Galileo spacecraft indicates that an iron core may form Io’s center, thus giving Io its own magnetic field.

Io was discovered on 8 January 1610 by Galileo Galilei. The discovery, along with three other Jovian moons, was the first time a moon was discovered orbiting a planet other than Earth.

Eruption of the Tvashtar volcano on Jupiter’s moon Io, photographed by New Horizons.

Image credit: NASA/JPL/Galileo/New Horizons ( Stuart Rankin, Kevin Gill)

Source: NASA

Wow

by NASA’s Juno spacecraft.

jupiter

Jupiterʼs moons

Ganymede, Callisto, Io and Europa