OrbitalHub

A piece of rock on the inner rim of Jezero Crater was soaked at least three times by very different waters over the course of Martian history, and NASA's Perseverance rover has now read each of those chemical signatures off the same outcrop. The work, led by Candice Bedford at Purdue University, appears in the journal Communications Earth & Environment and was published online on September 21, 2026 (NASA Mars news, Sep 21 2026; Sci.News coverage). It turns a single strip of terrain along the crater's former shoreline into one of the more interesting astrobiology sites on the planet, and it quietly resets a long-running debate about how the rocks there formed in the first place.

The location in question is called the Margin Unit, a band of rock that hugs the inner edge of Jezero's rim where the ancient lake that once filled the crater met dry land. Mission scientists had been puzzling over it since before Perseverance even landed. Orbital instruments had shown strong carbonate signals along that shoreline, and carbonates are the sort of mineral that on Earth usually forms in shallow, life-friendly water, so the natural expectation was that the Margin Unit would turn out to be sedimentary rock, the layered, sandy stuff that is great at trapping microbial remains. Instead, Perseverance's instruments showed that the band is mostly olivine-rich igneous rock, a coarse-grained material that on Earth typically crystallizes slowly underground from cooling magma. The carbonates are there, but they are not the original rock. They are an overprint, and the new paper unpacks how three separate waters, each with a different temperature and chemistry, left their own overprint on the same parent material over time (Universe Today, Sep 24 2026). That detail matters because the Margin Unit sits inside one of the largest carbonate exposures on Mars, and Jezero itself has been the centerpiece of NASA's most ambitious astrobiology campaign in decades. If the orbital carbonate signal really does trace a single ancient lake, then the carbonates are essentially a fossil of that lake, and they should record the chemistry of habitable water. If the carbonates instead reflect a much messier history of groundwater, hydrothermal fluids, and lake water acting on the same rock at different times, the carbonates are not a snapshot of habitability, they are a stack of snapshots. Bedford's team argues it is the latter, and they have the chemistry to show it.

The paper is built on more than 185 rock targets, all measured by SuperCam, the laser-and-spectrometer instrument perched on Perseverance's mast. SuperCam fires a laser up to 6.5 meters away at a target rock and reads the spectrum of the resulting plasma to determine the rock's chemistry. Across roughly 265 meters of vertical relief in the Margin Unit, the team at high elevations saw what they expected from a deep, slow-cooled igneous body: coarse olivine crystals with essentially no sign that water had ever reached them. About 265 meters lower, at the elevation where the ancient lake would have lapped against the crater wall, the same parent rock looks transformed. The olivine grains are fractured, and silica has filled the spaces between them. Some of those silica-bearing samples also contain the calcium-sulfate and fluorite veins that mark a third, much hotter stage of alteration (Space.com coverage). The sequence the team proposes runs as follows. Long before any lake existed in Jezero, carbon-dioxide-rich groundwater percolated through cracks in the olivine-rich bedrock. Where that groundwater met the right minerals, it produced carbonate. As the softer host rock around those carbonate-filled fractures eroded away over billions of years, the carbonates were left standing as ridges, which is the texture that first drew orbital attention to the Margin Unit in the first place. Then, in a window that the team cannot date precisely, water that may have been the Jezero paleolake, or a shift in the chemistry of groundwater connected to the lake, washed through the rock again. This second event partly remobilized the early carbonates and dropped silica into the pore spaces, with more silica appearing in rocks that sit below what would have been the old waterline. Finally, a third water event, this one clearly hotter, drove fluids through younger fractures in the eastern Margin Unit and deposited 25-centimeter-thick veins of calcium sulfate and fluorite. Fluorite, in particular, is a fingerprint of hydrothermal activity on Earth, and finding it on Mars is a strong hint that hot water was circulating through volcanic terrain long after the lake was gone.

Bedford has been working with Mars rovers for a decade, and her framing of the result is worth the gravity. "It is very rare that things are as we expect them to be from orbital data," she said in a NASA press release accompanying the paper, adding that she hopes the work helps reshape how scientists view the history of water in Jezero and across Mars, and ultimately helps reconstruct the changing climate and habitability of early Mars (NASA Mars news). Her co-author Eleni Ravanis, who works on the SuperCam team at the University of Hawaii at Manoa, made a more specific point about what the silica signal is actually telling us: turning olivine into carbonate leaves silica behind, so the more silica you see, the closer the rock sat to the waterline, which makes silica a kind of paleoshoreline marker for a lake that no longer exists. The implication is that the Margin Unit is not just a place where water once flowed, it is a place where water acted multiple times, with each event leaving its own chemical signature stacked on top of the last.

Astrobiologically, that stacking is the most interesting part. On Earth, the reaction between water and olivine can release hydrogen, and there are microbes that can live off that hydrogen. The reaction also leaves behind carbonate and silica, both of which are good at preserving traces of those microbes. So a rock that has been soaked, reheated, and re-soaked in different fluids is not a worse biosignature target than a rock that has only been touched once. It is a record of a longer, more complicated habitability window, and the chemistry preserved inside it is denser. Perseverance has already drilled and cached samples from the Margin Unit, including cores named Pelican Point and Lefroy Bay, and those samples are expected to be among the most prized tubes in the future Mars Sample Return campaign. If any of those cached samples turn out to carry organic material, this paper will be the document that explains why those particular rocks were the right ones to pick up. The image below is a 360-degree Mastcam-Z panorama of Turquoise Bay, a region inside the Margin Unit, captured between October 5 and October 16, 2023, sols 933 through 944 of the mission, and it shows the kind of rolling, weathered terrain that SuperCam has been analyzing ever since (NASA Photojournal PIA26815).

Abstract

The blogpost explores relativistic effects on proof-of-work based cryptocurrency protocols. Cryptocurrencies are here to stay and it is quite plausible that future human colonists spread across the solar system and beyond will use a decentralized cryptocurrency as opposed to a fiat currency issued by a central authority. The low transaction fees, the ubiquitous access, not being bound by exchange rates or interest rates, not being controlled by financial institutions who are serving foreign interests -- these are some of the advantages cryptocurrencies will enjoy in the thriving exo-economy.

Motivation

At present, on a cryptocurrency network, the information exchanged by the nodes in the network reaches each node almost instantaneously. The speed at which the TCP/IP packets travel on the network and the fact that the Internet spans only the Earth and the LEO makes this possible. However, once the region the network is spread across will reach certain boundaries, the network size would have negative impact on the network: increasing communication failures due to network delays, more frequent and longer blockchain forks as part of the proof-of-work protocol, network segregation into local sub-networks (let us call them topological forks), just to name a few.

Nullius in verba... as they say. Let's go deeper into details and figure out a feasible solution for a truly interplanetary cryptocurrency.

Cryptocurrency 101

You can think of a cryptocurrency as a digital money ecosystem. Plain and simple. A collection of technologies are part of this ecosystem, all of them the result of years of research in the cryptography and distributed systems fields: a decentralized network of computers, a public transaction ledger -- also known as a blockchain, a protocol that consists of a set of rules for transaction validation, a decentralized consensus mechanism. [ANTO]

A decentralized network of computers ensures the resilience of the network. We can think of both computing power and data storage capabilities. As the computing power is distributed across the network, any disruption can be successfully handled by the network. Transaction data resides on all nodes of the network. This implies that even physical damage done to network nodes will not take out the network.

The blockchain is a public distributed ledger which stores all transactions handled by the network. As the name suggests, the blockchain is a list of data blocks. Each of these blocks contains a set of transactions, as many as can fit in the block, given the maximum size of the block (a characteristic of the network). Transactions contain sender and receiver info, and the amount/asset that is changing ownership, and they are broadcasted and added to blocks by network nodes. Blocks are linked to the previous block in the chain by a cryptographic hash (the hash of the previous block becomes part of the current block). This backward link leads all the way to the first block in the chain, the Genesis block. Each cryptocurrency blockchain has one. The cryptographic hashes have an important role in protecting the blockchain from tampering attempts.

The transaction validation rules enforced by the nodes in the network ensure that the content of each block in the blockchain is valid. By far, the most frequent form of fraud is double spending. The validation process makes sure that the inputs on the transactions exist and that they have not been already spent. The transactions marked as invalid are rejected by the network and do not make it on the blockchain.

The consensus mechanism is designed so that all the nodes in the network can agree on the set of transactions to be included in the current block. It shifts the authority and the credibility required by a central clearing house to a network of nodes. Important to mention here that, inherently, the nodes do not trust each other, and they do not have to because the trust is enforced by the consensus mechanism itself.

The Proof-of-Work

We mentioned above that one of the key innovations that make cryptocurrencies possible is the decentralized consensus mechanism. Currently, the de facto consensus mechanism is the proof-of-work.

The proof-of-work consensus mechanism was proposed by Satoshi Nakamoto in 2008 [NAKA]. In general, a proof-of-work is a piece of data that requires costly and time consuming computational effort, but it is very easy to verify. A very good analogy is one of your semester projects in college... it takes you a whole semester to finalize it, but it takes very little time and effort for your supervisor to evaluate and grade it. Similarly, proof-of-work is used by cryptocurrencies for block generation. For the network to accept the block, nodes must complete a proof-of-work which also guarantees the integrity of the transactions included in the block. The difficulty of the proof-of-work is adjusted by the network so that a new block can be generated every fixed time interval. This fixed time interval is characteristic to every cryptocurrency. Most notably, for Bitcoin this time interval is set to 10 minutes.

Satoshi Nakamoto's solution, emobodied by the proof-of-work algorithm above, achieves consensus on the network without a central trusted authority (hence the name decentralized consensus mechanism).

Enter the Ansible

For the astute reader, it is quite obvious at this point that communication delays between the network nodes have a direct effect on the protocol described above. An important assumption made when the protocol was designed is that these delays are small, and this is why they can be handled by the network when the nodes choose to follow and validate the blocks on the longest blockchain fork. Also, this is the reason why all the nodes in the network can have a say in the network consensus. They all can find a solution for the current block, and they all can be rewarded when they find the solution. The communication delays witnessed by the peripheral nodes will cripple their ability to find solutions and these nodes will not be incentivized to remain in the network. Hence, the segregation of the network effect mentioned earlier.

Unfortunately, given the current technological level of our civilization, we do not have at our disposal a technology that allows us to communicate fast and reliable over the large expanse of space. It would take a hell of a wait time to proces a payment made by a mining corporation in the TRAPPIST-1 system, 12 parsecs within the constellation of Aquarius, to a planetary engineering corporation located in the Sol system... twice 39 years plus the block confirmation time.

Fortunately, the Sci-Fi literature already offers a solution for our problem. For those of you, Sci-Fi nerds like myself, that have already read Rocannon's World [LEGU] and Ender's Game [CARD], the Ansible device must sound very familiar. The ansible is a fictional device capable of faster-than-light communication. To word this differently, an operator of such device can send and receive messages to and from another device over any distance with no delay.

Hence, even if only in the realm of science fiction, we will be able to devise a solution for the problem that the future cryptocurrency enthusiasts, living in the outer space colonies, will eventually face.

The Special Relativity Theorem

Before elaborating more on a required upgrade of the network protocol, we have to discuss the special relativity theorem and its implications on how time and distance are perceived in reference systems.

Albert Einstein was awarded the Nobel Prize in Physics in 1921. He received it for his contributions to the understanding of the photoelectric effect, after publishing a paper on it in 1905. At that point his contributions to the understanding of gravity through his theory of relativity were well known, but the new perspective on gravity offered by Einstein's theory was so controversial that the Nobel Prize Committee members chose to protect their reputation. They decided that it was appropriate to award Einstein the Nobel Prize for "his services to theoretical Physics, and especially for his discovery of the law of the photoelectric effect."

During his research Einstein attempted to reconcile the principle of relativity with the principle of the constancy of the velocity of light. This attempt led Einstein to the discovery of the special relativity theorem. Einstein's Gedankenexperiment (thought experiment) with a test subject travelling by train is very well known in the scientific community. If our human subject is walking towards the front of the train with velocity w with respect to the train, and the train is moving with velocity v with respect to the embankment, then an observer on the embankment will measure as W = v + w the velocity of our subject on the train. If instead of our traveller, we consider a beam of light propagating with velocity c, the velocity measured by the observer on the embarkment would be v + c. However, this violates the principle that the velocity of light is constant in any inertial reference system and equal with c. Einstein found a solution for this problem and thus resolved the incompatibility.

One direct consequence of the special relativity theorem is the Lorentz transformation.

Before the relativity theorem, time in physics had an absolute significance, independent of the state of motion of the reference system. However, every inertial reference system has its own particular time. We always have to be told which inertial reference system the statement of time refers to. If you look at your watch, the time you read is the time as measured in the Earth inertial reference system. By the way, the Earth circles the Sun on an almost circular orbit, which means that any body maintaining a constant position in the Earth reference system should experience some centripetal force. However, this centripetal component is negligible compared to the gravitational pull of the Earth. Hence, engineers use this aproximation when calculating satellite orbits.

Back to our original trail of thoughts... the axiom that lays the foundation for the Lorentz transformation states that every ray of light possesses the velocity of transmission c relative to any inertial reference system. That is the velocity of transmission in vacuo (in a vacuum).

If following Einstein's thought experiments [EINS], the above-mentioned axiom leads to a set of four equations that explain the relation between dimensional and temporal coordinates in two inertial reference systems:

  x' = (x - vt)/sqr(1 - v²/c²)
  y' = y
  z' = z
  t' = (t - x*v/c²)/sqr(1 - v²/c²)

where:

 x, y, z, t coordinates in inertial reference system K,
 x', y', z' , t' coordinates in inertial reference system K',
 v the relative velocity between inertial reference systems;

also, the expression 1//sqr(1 - v²/c²) is known as the Lorentz factor.

The Lorentz transformation equations are a more general case of the Galilean transformation:

  x' = x - vt
  y' = y
  z' = z
  t' = t

which is the basis of the assumptions of the classical mechanics as to the absolute character of both dimensional and temporal coordinates. The above are the result of replacing velocity c with ∞ in the Lorentz transformation equations.

The Lorentz transformation has a few corollaries which have an impact on time dilation, length contraction, relativistic mass, relativistic momentum, and relativistic kinetic energy. The one that concerns us is the time dilation corollary:

 Δt = γΔt'
 
where γ is defined by

 α = 1/γ = sqr(1 - v²/c²)

Assuming a clock at rest in inertial reference system K, and moving with the velocity v in the inertial reference system K', the time Δt' between two ticks as measured in the frame K' is longer than the time Δt between the same ticks as measured in the rest frame of the clock, K.

Relativistic Effects on Proof-of-Work

To better understand the relativistic effects on how relative time is perceived in two inertial reference systems (or Galilean reference systems [EINS]) we have to mention the twin paradox. The twin paradox is a thought experiment that involves two identical twins. One of the twins makes a journey into space onboard a relativistic spaceship, and upon his return to Earth discovers that his twin has aged much more than he did. Depending on how fast the spaceship moves through space and/or how long the journey was, our traveller could return to Earth and realize that several generations have passed meanwhile.

As a direct application of the twin paradox, we have Mazer Rackham, International Fleet Admiral and Ender Wiggin's mentor, as portrayed by Orson Scott Card [CARD]. The fighter pilot who destroyed the Formic Fleet Flagship, killed the Hive Queen, and ended the Second Formic Invasion, Mazer Rackham is sent on a journey on a relativistic spaceship and returns to Earth 100 years later in order to assist the International Fleet. Upon his return he has barely aged a few years.

Similarly, if a subnetwork is moving relative to the rest of the network, the nodes in the subnetwork would experience time dilation as predicted by the special relativity theorem. Hence, they are at a disadvantage compared to the rest of the nodes because they have less time available to find a solution for the proof-of-work problem. In order to make thing square for all the nodes in the network, the difficulty of the problem should be adjusted in each subnetwork using the Lorentz factor: in order to compensate for time dilation, the relativistic nodes should have to solve a simpler problem. Also, their block confirmation time should decrease as well.

One element is missing still... how do ansibles synchronize? What value has the Lorentz factor for each one of them? One simple solution for this problem is having one of the ansibles (let us say the Earth-bound one) broadcasting a beacon every fixed number of seconds. The ansibles interfacing to subnetworks would pick up the broadcast, and by measuring the time interval between the beacons, infer the Lorentz factor. Once the Lorentz factor is determined, the nodes mining on the subnetworks will have their proof-of-work difficulty and the block confirmation time adjusted accordingly.

A more Down-to-Earth Solution for the Problem

We will fork the storyline (pun intended) at Enter the Ansible paragraph, and suggest a more down-to-earth solution for the problem. The peripheral nodes are not to participate in the consensus. Their function would be just to relay messages (a.k.a. payment information) across the network. In our multi-planetary scenario, the nodes working on the proof-of-work would reside on/around the Earth, and the network nodes on Mars or any other region in the Sol system would have to wait 2x (network packets travel time) + (block confirmation time) in order to confirm a payment. However, such a solution would have an Achilles heel very hard to defend... if starting its mining engine, any peripheral node could take over the local network and force a topological fork of the network. For a node, the incentive of staying honest on the current network must be stronger than any reward obtained by cheating.

Concluding remarks

While the blogpost contains some elements of fiction, it accurately describes the cryptocurrency ecosystem, the special relativity theorem, the Lorentz transformation and its corollaries. We would like to thank the readers that went through this exercise with us. Undeniably, cryptocurrencies are disrupting the global economy and they are here to stay. Undeniably, we -- as a species -- will explore and migrate farther than the LEO. History has taught us that decentralization is the key to survival and prosperity. Let us together make the future happen.

References

[ANTO] Antonopoulos, Andreas M., Mastering Bitcoin, Second Edition, O'Reilly Media, Inc., June 2017;
[CARD] Card, Orson Scott, Ender's Game, A Tor Teen Book, 2014;
[EINS] Einstein, Albert, Relativity, The Special and the General Theory, Princeton University Press, 2015;
[LEGU] Le Guin, Ursula K., Rocannon's World, Harper & Row, 1977;
[NAKA] Nakamoto, Satoshi, Bitcoin - A Peer-to-Peer Electronic Cash System, www.bitcoin.org, 2008;