Mars scientists are wrestling with a problem. Ample evidence says ancient Mars was sometimes wet, with water flowing and pooling on the planet’s surface. Yet, the ancient sun was about one-third less warm and climate modellers struggle to produce scenarios that get the surface of Mars warm enough for keeping water unfrozen.
A leading theory is that ancient Mars had a thicker carbon-dioxide atmosphere forming a greenhouse-gas blanket, helping to warm the surface. However an analysis of data from NASA’s Mars rover Curiosity, suggests that even 3.5 billion years ago there was too little carbon dioxide present in the Martian atmosphere to provide enough greenhouse-effect warming to prevent water freezing.
The source of these findings is the very same bedrock in which the rover found sediments from an ancient lake in which microbes might have thrived. When analysing the bedrock, Curiosity detected no carbonate minerals, leading to the conclusion that Mars’ atmosphere was almost devoid of carbon dioxide when the lake existed 3.5 billion years ago. And that’s a quandary for scientists.
“We’ve been particularly struck with the absence of carbonate minerals in sedimentary rock the rover has examined,” Thomas Bristow, the principal investigator for Curiosity’s Chemistry and Mineralogy (CheMin) instrument, the primary source of the analysis work. “It would be really hard to get liquid water even if there were a hundred times more carbon dioxide in the atmosphere than what the mineral evidence in the rock tells us.”
In water, carbon dioxide combines with positively charged ions such as magnesium and ferrous iron to form carbonate minerals, and CheMin can identify carbonate if it makes up just a few percent of the rock. Yet Curiosity has made no definitive detection of carbonates in any lakebed rocks sampled since it landed in Gale Crater in 2012. However, other minerals – magnetite and clay minerals – not only indicated in the same rocks indicate the ions needed to form carbonates were readily available, they also provide evidence that subsequent conditions never became so acidic that carbonates would have dissolved away over time.
The dilemma between a warm, wet Mars and the lack of carbonates has actually been growing for years. For two decades researchers have been using spectrometers on Mars orbiters to search for carbonate that could have resulted from an early era of more abundant carbon dioxide in the atmosphere, only to find far less than anticipated. Yet clues such as isotope ratios in today’s Martian atmosphere continue to indicate the planet once held a much denser atmosphere than it does now, which has largely been seen as being rich in carbon dioxide. Thus, a paradox has arisen.
It had been thought that the lack of evidence for carbonates when seen from orbit could simply be the result of dust covering them, or the carbonates having moved underground. Finding them would thus resolve the paradox and reveal what had happened. However, the Curiosity results tend to overturn this idea. Simply put, the rover has failed to detect carbonate minerals precisely where they should be located, within rocks formed from sediments deposited under water.
“This analysis fits with many theoretical studies that the surface of Mars, even that long ago, was not warm enough for water to be liquid,” said Robert Haberle, a Mars-climate scientist at NASA Ames. “It’s really a puzzle to me.”
One idea put forward is that perhaps the lake was never a body of open water, but was covered in ice. The problem with this idea is none of the expected evidence for an ice-covered lake, such as large and deep cracks called ice wedges, or “dropstones,” which become embedded in soft lakebed sediments when they penetrate thinning ice, have been found. Thus, scientists have a lot of head scratching and theorising to do in order to make sense of the dilemma.
Traversing Mars with Curiosity
Ever wondered what it would be like to witness Curiosity trundling across the surface of Mars? Seán Doran has. What’s more, he’s been putting together animated films using Digital Terrain Model (DTM) data from the HiRISE imaging system on NASA’s Mars Reconnaissance Orbiter together with photomosaics of images from the rover, and combining them with a drivable correctly scaled model of the rover to provide movies of Curiosity as it rolls across Mars.
The videos are a fantastic piece of work – only the rover’s speed isn’t accurate: scaled as it is, it is moving at some 8 km/h (5 mph), rather than the move usual 0.16 km/h. All of the details are as accurate as Seán could make them from the data and images available – he even went so far to match the sun angle and shadows with those from the photomoasics. Click the image below to view one of Seán’s videos for yourself.
Hubble Finds the Earliest Galaxies Yet Discovered
Thanks to a technique developed by astronomers at The University of Texas, coupled with a useful optical effect predicted by Albert Einstein, the Hubble space Telescope has discovered the faintest galaxies yet seen in the early universe, 10 times fainter than any previously seen, and which may be among the first to give light in what had otherwise been a largely dark universe.
The really old galaxies are actually thought to be extremely common, most of them dating from around one billion years after the universe came into being with the Big Bang. However, they are exceptionally difficult to locate because they tend to be blanked out by the light of much younger and closer (in a cosmic sense) galaxies.
The new technique essentially acts as a “light cancellation system” somewhat similar to the wizardry found in noise cancelling headphones, to eliminate the light of those nearer, younger galaxies, revealing the light of the much older, more distant ones.
In particular, the technique leverages galactic clusters – large groups of galaxies in relatively close proximity to one another when viewed from Earth. Such clusters and enormous mass, and as predicted by Einstein, this effectively “bends” space, magnifying the light from more-distant galaxies “behind” the cluster.
These galaxies date from the Epoch of Reionization, the time at which the first stars – population III stars – formed, with the first galaxies following them, as the hydrogen in the universe was reionised. These early galaxies in turn further powered the reionisation process, giving rise to more galaxies, up to and including the formation of our own, around 9 billion years after the Big Bang. However, until their discovery, they were stuck within the realm of theory, rather than known fact.
Launch Pad 39A: About to Re-enter Service
It’s possibly the most famous rocket launch site in the world: Kennedy Space Centre’s Launch Complex 39, comprising two launch pad facilities: Pad 39A and Pad 39B. Between them they were the starting point for every Apollo and space shuttle space mission – with Pad 39A being the starting point for all but one of the Apollo Saturn V launches.
Since the end of the shuttle era neither of these pads has been used – which is not to say they have been deserted. NASA has been busy with Pad 39B, reverting it to a “clean” state ready to become a multi-purpose launch site for different vehicles. Some of which will lift-off from a smaller, new Pad 39C sitting within its perimeter (the so-called “launch pad in a box), and others – notably the mighty Space Launch System – will use the main Pad 39B facilities from 2018 onwards.
Pad 39A, however, was leased to SpaceX in 2014, and since then has undergone major refurbishment by the company in order to support Falcon 9 and Falcon Heavy launches and – it would now seem – potentially the launch of the company’s gigantic Interplanetary Transportation System rocket. And on February 10th, 2017, the first Falcon 9 rocket was rolled out from the new SpaceX Horizontal Integration Facility, located at the edge of the launch pad facilities (and capable of handling up to five Falcon rockets at a time), and moved to the launch pad, where it was raised to a vertical position in readiness for a February 18th launch on a Dragon resupply mission to the International Space Station.
While the launch awaits final FAA clearance, SpaceX hopes that it will not only serve to inaugurate the re-vamped Pad 39A, but will allow the company to start ramping its schedule to a potential launch every three weeks, particularly once repairs have been completed to Launch Complex 41 at Canaveral Air Force Station just south of Kennedy Space Centre, which was extensively damaged when a Falcon 9 rocket exploded during a pre-flight test on September 1st, 2016.
SpaceX’s Florida Competition
SpaceX will soon face private sector competition flying out of Florida. Jeff Bezos’ rocket company Blue Origin has begun site preparation for an orbital launch complex and rocket engine test stand which will be built on the site of the Launch Complex 36 at Cape Canaveral Air Force Station in Florida. When Complete, the 300-acre site will be used to test the company’s BE-4 rocket motor and to launch their New Glenn family of reusable heavy launch vehicles.
The new launch complex will be Blue Origin’s second major construction project at the Cape. In May 2016, the company broke ground on a 750,000 square-foot plant near NASA’s Kennedy Space Centre where it will manufacture and assemble the New Glenn rockets.
Seven metres (23ft) in diameter, the New Glenn first stage will be powered by seven of the company’s new BE-4 engines. These are the same engines United Launch Alliance have selected as the primary propulsion unit for their own upcoming new Vulcan launch vehicle, which will enter service in 2019 to replace the expensive Atlas V booster.
This core stage of the new Blue Origin rocket – which is named for John Glenn, the first American to orbit the Earth – will be reusable, just like the first stages of the SpaceX Falcon 9 and Falcon Heavy.
The New Glenn will be topped by either a second stage for launches to low-Earth orbit, or a combination of a second stage and third stage system capable of a broader range of launch options. It is anticipated the vehicle will be capable of lifting between 35 to 70 tonnes to low Earth orbit, placing it in the same class of launch vehicle as SpaceX’s Falcon Heavy – and thus competing directly with it.
The company expects to be in full production with the New Glenn by 2017, and make their first launch from the new facilities in 2020.
A journey to Jupiter
In 2014, Peter Rosen, a photographer, digital artist and amateur astronomer in Stockholm, Sweden, put out a call to amateur astronomers around the world for assistance in producing a new animated film focused on Jupiter. In all, 91 “citizen scientists” – including Rosen himself, together with colleagues Christoffer Svenske and Johan Warell – spent just over three months between Mid-December 2014 and the end of March 2015) imaging Jupiter to produce over 1,000 images of the planet.
For more than a year following this, Svenske and Warrell carefully remapped the images into a set of cylindrical projections of the planet, before Rosen then colour corrected the projections, stacked them correctly, and seamlessly stitched them together to create a total of 54 complete maps of Jupiter. These were then composited together to produce a fabulous four-and-a-half minutes video, presenting some unique views of the planet.
It’s a captivating film – as you can see below. It stands as both an artistic presentation and a highly accurate model of the rotating Jupiter and the actions and interactions within its atmosphere – so much so that Ricardo Hueso Alonso – a physicist at the University of Basque Country and a member of the Planetary Virtual Observatory and Laboratory (PVOL) – plans to use the maps to measure Jupiter’s wind speeds at different latitudes.
Of the film, Rosen says, “This has been a very technical and scientifically correct project. But as a photographer and digital artist I also wanted to create a work of art that would inspire and appeal to people who are fascinated by the universe but who are not necessarily into astronomy.”
When you watch the film I think you’ll agree he’s succeeded in his aims.