Tag: exploration

Mars Dust Storm

For nearly a month, a series of severe Martian summer dust storms has affected the rover Opportunity and, to a lesser extent, its twin, Spirit. The dust in the Martian atmosphere over Opportunity has blocked 99% of direct sunlight to the rover, leaving only the limited diffuse sky light to power it. Scientists fear the storms might continue for several days, if not weeks.

i was just wondering how long those rover tracks would last.

Interstellar

Multi-Generation Space Ships

the motivations, technology, and prospects for interstellar flight, while the balance deals with anthropological, genetic, and linguistic issues in crew composition for a notional mission with a crew of 200 with a flight time of 2 centuries.

2007-06-15: On the infeasibility of interstellar travel

We require the equivalent energy output to 400 megatons of nuclear armageddon in order to move a capsule of the gross weight of a fully loaded Volvo V70 automobile to Proxima Centauri in less than a human lifetime. That’s the same as the yield of the entire US Minuteman III ICBM force. Our entire planetary economy runs on 4TW. So it would take our total planetary electricity production for a period of 5 days to supply the necessary va-va-voom.

2009-02-01: Tau Zero Foundation

The Tau Zero Foundation is a volunteer group of scientists, engineers, entrepreneurs, and writers who have agreed to work together toward practical interstellar flight and to use this quest to teach you about science, technology, and our place in the universe.

2010-05-07: Project Icarus

To design a credible interstellar probe that is a concept design for a potential mission in the coming centuries.

2011-01-06: No Interstellar Travel Before 2200. About 10^18 Joules required, more than a Kardashev type I civilization.
2011-05-20: Star Children. It might make sense to start a religion to ensure long term space travelers retain their goals.

We are seeking ideas for an organization, business model and approach appropriate for a self-sustaining investment vehicle. The respondent must focus on flexible yet robust mechanisms by which an endowment can be created and sustained, wholly devoid of government subsidy or control, and by which worthwhile undertakings—in the sciences, engineering, humanities, or the arts—may be awarded in pursuit of the vision of interstellar flight

2013-04-25: Starship Century

Is this the century we begin to build starships?

yes

2014-03-12: Starship Century

Starship Century is a symposium coordinated by the new Arthur C. Clarke Center for Human Imagination in collaboration with Gregory and James Benford, presenting ideas from their anthology of science and science fiction. First 8 minutes most of them agree the era of interstellar starships will be 100-300 years away after there is lot of solar system development.

2015-10-21: Black hole drive

The petawatt Hawking radiation of γ-ray laser-created subatomic black holes (Schwarzschild Kugelblitzes or SKs) has been proposed as a propulsive and power source for interstellar starships. Production of a black hole requires concentration of mass or energy within the corresponding Schwarzschild radius. In familiar 3D gravity, the minimum such energy is 10^19 GeV, which would have to be condensed into a region of approximate size 10^-33 cm. This is far beyond the limits of any current technology; the Large hadron collider (LHC) has a design energy of 14 TeV. This is also beyond the range of known collisions of cosmic rays with Earth’s atmosphere, which reach center of mass energies in the range of 100s of TeV. It is estimated that to collide 2 particles to within a distance of a Planck length with currently achievable magnetic field strengths would require a ring accelerator ~1k light years in diameter to keep the particles on track.

2016-02-20: Interstellar Propulsion. A 100kg robotic craft could be sent to Mars in 3 days with the power levels that large rockets produce (50-100 GW)

2016-04-12: Starshot. This makes me proud of our civilization: We do stuff like this.

Milner wants his $100M to fund research that will culminate in a prototype of a probe that can beam images back to Earth. The images would arrive less than 5 years after the probe reached the star.

There are no official specs yet, but the probe would have a 2-megapixel camera, along with star-finders to help it get its bearings, after it boots up on the approach to Proxima Centauri. The probe will target one of the system’s 2 sunlike stars. It will be aimed at a planet (or planets) in the star’s habitable zone, the temperate region where oceans don’t boil or freeze, but instead flow, nurturing the kind of complex chemistry that is thought to give rise to life.

2018-08-14: Propellantless interstellar travel

Researchers propose a new mode of transport which relies on electric-field moderated momentum exchange with the ionized particles in the interstellar medium. While the application of this mechanism faces significant challenges requiring industrial-scale exploitation of space, the technological roadblocks are minimal, and are perhaps more easily addressed than the issues presented by light sails or particle beam powered craft. This mode of space travel is particularly well suited to energy efficient space travel at velocities less than 5% of light speed, and compares exceptionally well to light sails on an energy expenditure basis. It therefore represents an extremely attractive mode of transport for slow (~multi-century long) voyages carrying heavy payloads to nearby stellar neighbors. This could be very useful in missions that would otherwise be too energy intensive to carry out, such as transporting bulk materials for a future colony around Alpha Cen A, or perhaps a generation ship.

2020-02-21: Interstellar Probe, weighing a few grams, and getting there in 20 years.
2020-09-03: Mach Effect Propulsion. Jim Woodward is investigating mach effect thrusters as part of NASA NIAC. If successful, this will get us to .xc, making humanity interstellar.
2022-08-05: Bow Shock Deceleration

Deceleration at the destination system is a huge problem for starship mission planning. A future crew, human or robotic, could deploy a solar sail to slow down, but a magsail seems better, as its effects kick in earlier on the approach. Looking at the image below, however, suggests another possibility, one using the interactions between stars and the interstellar medium to assist the slowdown. The bow shock produces 3D structures, surfaces within which one can move while shedding speed, perhaps braking via a magsail. Each star would produce its own unique deceleration environment, allowing us to brake where possible along the bow shock, the astropause (cognate to the heliopause) and the termination shock.

Microbiome

Human microbiome program?

Because of the importance of beneficial / commensal microbes in human biology, there have been growing efforts to characterize the microbes in various body locations – gut, mouth, lungs, skin, etc. But the efforts so far have simply given a tantalizing taste of how interesting and important these microbes are. So here comes this meeting. Organized by NIH (specifically, Francis Collins at NHGRI), this workshop is geared to discuss the possibility that studies of the human microbiome will be included in the next list of “NIH Roadmap” programs. More on the NIH Roadmap some other time.

Basically, the general idea is – do we need an big scale, organized program to tackle the human microbiome.? To get us in the mood, we had talks by many of the pioneers/leaders in the field (e.g., David Relman, Jeff Gordon, Jim Tiedje) as well as discussion of the NIH Roadmap program. I personally did not need any convincing but it was good to hear some of the ideas presented. In the end, I think there is no doubt that a large scale Human Microbiome Program is needed and would be very beneficial.

In addition to the 10 trillion human cells, there are 100 trillion bacterial cells in a body. Our metagenome may be 100x the human genome.
2010-10-30: Space Standard Microbiome. Venter suggests NASA should replace the microbiome (bacteria species) of astronauts with a standardized, synthetic one to improve survivability of space flight.
2012-06-15: 0.3% Human

Where the human genome carries some 22K protein-coding genes, the human microbiome contributes some 8M protein-coding genes responsible for human survival: 360x more.

The microbiome is one of the most fascinating areas in biology:

in many mammals a microbial community ferments various sweats, oozes and excretions into distinctive scents that reveal age, health and much more to knowing noses in a select social circle.

That’s right, microbes are posting status updates to each other through smells, sharing with other microbes what they’ve learned about host animals.
2012-12-08: American Gut looks amazing. I will of course participate. Since you are only 10% human (the rest is bacteria), even if you do 23andme you don’t really know yourself at all. $99 for 1 bacterial DNA kit, $180 for 2. There are also higher levels, up to the $25k ultra-deep sequencing of your microbiome sample aimed at generating as many individual bacterial genomes as possible.
2015-03-03: a nice summary of The American Gut project

2016-10-01: Poop Bot. As usual, onion’s satire is leading the way:

you can tell the most about someone by sampling their microbiome, and “the sewage system is the great aggregator.” Gross, sure, but Ratti is studying waste to understand everything from heroin use to antibiotic-resistant bacteria—and all with the help of a sewer-slurping robot named Luigi.

2017-09-05: Microbiome 99% unknown

A survey of DNA fragments circulating in the blood suggests the microbes living within us are vastly more diverse than previously known. In fact, 99% of that DNA has never been seen before. The “vast majority” of it belonged to a phylum called proteobacteria, which includes, among many other species, pathogens such as E. coli and Salmonella. Previously unidentified viruses in the torque teno family, generally not associated with disease but often found in immunocompromised patients, made up the largest group of viruses.

2018-10-03: SynBioBeta 2018

In 15 years, brain interfaces will be as common as the cell phone. The radical experiment that has been run over the past 100 years shifting the microbiome of infants and provoking a wide array of immune disorders (allergies, asthma, diabetes)

2019-08-07: Microbiome Friendships?

Now that it is clear that social behavior plays a role in shaping the gut microbiome, the next question is whether microbiomes have had a meaningful impact on our social worlds. Scientists still do not have an answer, but they are tantalized by the possibilities, which could have implications for understanding the evolution of sociality.

2019-12-04: Microbiomes Affect Fear

microbiomes can influence the fear responses of their hosts, possibly by releasing compounds that affect the brain’s neuroanatomy and function.

2022-02-22: Space microbiome

Humans aren’t the only organisms that we have to consider when evaluating the impacts of space travel. While we are traveling on spaceships, microbes are traveling on us. Microgravity has been shown to alter bacterial growth patterns and kinetics, and radiation increases the frequency of mutations—in both cases creating opportunities for increased antimicrobial resistance—all in an environment where astronauts immune systems are compromised. The ISS has a complex microbiome that we fundamentally alter, and that in turn alters us. It’s important to be able to understand the genetic basis of antimicrobial resistance in space. A team of researchers carried out a study with the goal of addressing this question. A considerable number of AMR genes were found in several different locations for Kalamiella piersonii—a microbe potentially involved in causing urinary tract infections. Worryingly, “the potentially very pathogenic microbe E. bugandensis was found in location 2 (forward side panel wall of the Waste and Hygiene Compartment) in flight 1, presenting more than 40 ARGs.” They were also able to detect specific types of potential drug resistance for several microbes within the Pantoea species—which provided a higher level of resolution into observations made in their past analysis.

2023-01-19: person-to-person transmission

Mother-to-infant gut microbiome transmission was considerable and stable during infancy (around 50% of the same strains among shared species (strain-sharing rate)) and remained detectable at older ages. By contrast, the transmission of the oral microbiome occurred largely horizontally and was enhanced by the duration of cohabitation. There was substantial strain sharing among cohabiting individuals, with 12% and 32% median strain-sharing rates for the gut and oral microbiomes, and time since cohabitation affected strain sharing more than age or genetics did.

2023-05-04: Using dental plaque to reconstruct the oral microbiome

Reconstructing an oral microbiome—a soup of 100s of different bacterial species, and millions of individual bacteria—from degraded ancient DNA is “like throwing together pieces of many puzzles and trying to solve them with the pieces mixed up and some pieces missing entirely”.

It took 3 years to adapt DNA sequencing tools and computer programs to work with the much shorter fragments of DNA found in ancient samples. Drawing on dental calculus from 46 ancient skeletons—including a dozen Neanderthals and modern humans who died between 30k and 150 years ago, Warinner identified DNA from 10s of extinct or previously unknown oral bacteria.
Identified as a type of bacterium called a chlorobium, its modern relatives use photosynthesis to survive on small amounts of light and live in anaerobic conditions, such as stagnant water. They aren’t found in modern mouths and appear to have vanished from ancient humans 10 ka BP. This chlorobium might have entered the mouths of ancient people because they drank water in or near caves. Or it might once have been a normal part of some people’s ancient oral microbiome, surviving on faint light penetrating the cheek.

2023-06-08: Sample handling ruins many studies

The authors have tried all sorts of sample-handling variations, and it looks like they have had trouble finding any that don’t change the composition of the microbial samples themselves. Both papers investigated the 2 commercially available stool sample kits (OMNIgene and Zymo), and found that the latter was much more sensitive to temperature variations on storage. And both kits changed the absolute levels of various bacteria types: the OMNIgene-preserved samples had significantly higher amounts of Bacteroidetes species as compared to preservative-free controls, while the Zymo-preserved ones had significantly lower amounts. The second paper also finds that the method used for cell disruption can significantly affect the ribosomal RNA reads used to characterize the bacterial species as well.

Researchers in the field should also be measuring total bacterial load in their samples and monitoring that for signs of variability in their sample handling and people should standardize on 25 PCR cycles, because that can also change things. These effects can help explain the widely varying literature results in human microbiome studies.