Posted on by Evan Gough

Musk Says that SpaceX will use a Giant Party Balloon to Bring an Upper Stage Back. Wait, what?

Recovering and reusing boosters is getting routine for SpaceX. But they haven't recovered an upper stage booster yet. Is that about to change? Image: SpaceX

When Elon Musk of SpaceX tweets something interesting, it generates a wave of excitement. So when he tweeted recently that SpaceX might be working on a way to retrieve upper stages of their rockets, it set off a chain of intrigued responses.

SpaceX has been retrieving and reusing their lower stages for some time now, and it’s lowered the cost of launching payloads into space. But this is the first hint that they may try to do the same with upper stages.

Twitter responders wanted to know exactly what SpaceX has in mind, and what a “giant party balloon” might be. Musk hasn’t elaborated yet, but one of his Twitter followers had something interesting to add.

Quinn Kupec, a student at the University of Maryland’s James Clark School of Engineering tweeted to Musk:

Universe Today contacted Mr. Kupec to see if he could help us understand what Musk may have been getting at. But first, a little background.

An “ultra low ballistic entry coefficient decelerator” is a bit of a mouthful. The ballistic coefficient measures how well a vehicle can overcome air resistance in flight. A high ballistic coefficient means a re-entry vehicle would not lose velocity quickly, and would reach Earth at high speeds. An ultra low ballistic entry coefficient decelerator would lose speed quickly, meaning that a vehicle would be travelling at low, subsonic speeds before reaching the ground.

To recover an upper stage booster, low speeds are desirable, since they generate less heat. But according to Kupec, there’s another problem that must be overcome.

“What happens when these things slow down to landing velocities? If your center of gravity is offset significantly behind your center of drag, as would be the case with a returning upper stage, it can get unstable. If the center of gravity of the re-entry vehicle is too high, it can become inverted, which is obviously not desirable.”

So the trick is to lower the speed of the re-entry vehicle to the point where the heat generated by reentry isn’t damaging the booster, and to do it without causing the vehicle to invert or otherwise become unstable. This isn’t a problem for the main stage boosters that SpaceX now routinely recovers; they have their own retro-rockets to guide their descent and landing. But for the upper stage boosters, which reach orbital velocities, it’s an obstacle that has to be overcome.

“My research is specifically focused on how high you can push the center of gravity and still maintain the proper flight configuration,” said Kupec.

But what about the “giant party balloon” that Musk tweeted about?

Musk could be referring, in colorful terms, to what’s called a ballute. The word is a combination of the words balloon and parachute. They were invented in the 1950’s by Goodyear Aerospace. They can arrest the descent of entry vehicles and provide stability during the descent.

“…the balloon would have to be 120 ft. in diameter, and made of a high-temperature fabric…” – Professor Dave Akin, University of Maryland

Universe Today contacted Professor Dave Akin of the University of Maryland for some insight into Musk’s tweet. Professor Akin has been working on reentry systems for over 2 decades.

In an e-mail exchange, Professor Akin told us, “There have been concepts proposed for deploying a large balloon on a cable that is towed behind you on entry. The balloon lowers your ballistic coefficient, which means you decelerate higher in the atmosphere and the heat load is less.” So the key is to scrub your speed before you get closer to Earth, where the atmosphere is thicker and generates more heat.

But according to Professor Akin, this won’t necessarily be easy to do. “To get the two orders of magnitude reduction in ballistic coefficient that Elon has been talking about the balloon would have to be 120 ft. in diameter, and made of a high-temperature fabric, so it’s not going to be all that easy.”

But Musk’s track record shows he doesn’t shy away from things that aren’t easy.

Retrieving upper rocket stages isn’t all about lowering launch costs, it’s also about space junk. The European Space Agency estimates that there are over 29,000 pieces of space junk orbiting Earth, and some of that junk is spent upper stage boosters. There have been some collisions and accidents already, with some satellites being pushed into different orbits. In 2009, the Iridium 33 communications satellite and the defunct Russian Cosmos 2251 communications satellite collided with each other, destroying both. If SpaceX can develop a way to retrieve its upper stage boosters, that means less space junk, and fewer potential collisions.

There’s a clear precedent for using balloons to manage reentry. With people like Professor Akin and Quinn Kupec working on it, SpaceX won’t have to reinvent the wheel. But they’ll still have a lot of work to do.

Musk tweeted one other thing shortly after his “giant party balloon” tweet:

No word yet on what that might mean.

Elon Musk’s “giant party balloon” tweet: https://twitter.com/elonmusk/status/985655249745592320
Quinn Kupec’s tweet: https://twitter.com/QuinnKupec/status/985736260827471872

Posted on by Fraser Cain

Weekly Space Hangout: April 18, 2018: Kevin Gill: Art and Science from Juno and MRO

Hosts:
Fraser Cain (universetoday.com / @fcain)
Dr. Paul M. Sutter (pmsutter.com / @PaulMattSutter)
Dr. Kimberly Cartier (KimberlyCartier.org / @AstroKimCartier )
Dr. Morgan Rehnberg (MorganRehnberg.com / @MorganRehnberg & ChartYourWorld.org)

Special Guests:
Kevin Gill is a software engineer, planetary and climate data wrangler, and a science data visualization artist. Kevin will be discussing his work with Juno and MRO images. Check out his work at his Flickr page: https://www.flickr.com/photos/kevinmgill/ and his tech blog Apoapsys: http://www.wthr.us/ Follow Kevin on Twitter at: https://twitter.com/kevinmgill and Instagram here: https://www.instagram.com/apoapsys/

Announcements:
If you would like to join the Weekly Space Hangout Crew, visit their site here and sign up. They’re a great team who can help you join our online discussions!

We record the Weekly Space Hangout every Wednesday at 5:00 pm Pacific / 8:00 pm Eastern. You can watch us live on Universe Today, or the Weekly Space Hangout YouTube page – Please subscribe!

Posted on by Matt Williams

How to Listen to the Background Hum of Gravitational Waves From all the Black Holes Colliding into Each Other

Artist's impression of two merging black holes. Credit: Bohn, Throwe, Hébert, Henriksson, Bunandar, Taylor, Scheel/SXS
Artist's impression of two merging black holes. Credit: Bohn, Throwe, Hébert, Henriksson, Bunandar, Taylor, Scheel/SXS

The first-ever detection of gravitational waves (which took place in September of 2015) triggered a revolution in astronomy. Not only did this event confirm a theory predicted by Einstein’s Theory of General Relativity a century before, it also ushered in a new era where the mergers of distant black holes, supernovae, and neutron stars could be studied by examining their resulting waves.

In addition, scientists have theorized that black hole mergers could actually be a lot more common than previously thought. According to a new study conducted by pair of researchers from Monash University, these mergers happen once every few minutes. By listening to the background noise of the Universe, they claim, we could find evidence of thousands of previously undetected events.

Their study, titled “Optimal Search for an Astrophysical Gravitational-Wave Background“, recently appeared in the journal Physical Review X. The study was conducted by Rory Smith and Eric Thrane, a senior lecturer and a research fellow at Monash University, respectively. Both researchers are also members of the ARC Center of Excellence for Gravitational Wave Discovery (OzGrav).

Drs. Eric Thrane and Rory Smith. Credit: Monash University

As they state in their study, every 2 to 10 minutes, a pair of stellar-mass black holes merge somewhere in the Universe. A small fraction of these are large enough that the resulting gravitational wave event can be detected by advanced instruments like the Laser Interferometer Gravitational-Wave Observatory and Virgo observatory. The rest, however, contribute to a sort of stochastic background noise.

By measuring this noise, scientists may be able to study much more in the way of events and learn a great deal more about gravitational waves. As Dr Thrane explained in a Monash University press statement:

“Measuring the gravitational-wave background will allow us to study populations of black holes at vast distances. Someday, the technique may enable us to see gravitational waves from the Big Bang, hidden behind gravitational waves from black holes and neutron stars.”

Drs Smith and Thrane are no amateurs when it comes to the study of gravitational waves. Last year, they were both involved in a major breakthrough, where researchers from LIGO Scientific Collaboration (LSC) and the Virgo Collaboration measured gravitational waves from a pair of merging neutron stars. This was the first time that a neutron star merger (aka. a kilonova) was observed in both gravitational waves and visible light.

The pair were also part of the Advanced LIGO team that made the first detection of gravitational waves in September 2015. To date, six confirmed gravitational wave events have been confirmed by the LIGO and Virgo Collaborations. But according to Drs Thrane and Smith, there could be as many as 100,000 events happening every year that these detectors simply aren’t equipped to handle.

In February 2016, LIGO detected gravity waves for the first time. As this artist's illustration depicts, the gravitational waves were created by merging black holes. The third detection just announced was also created when two black holes merged. Credit: LIGO/A. Simonnet.
Artist’s impression of merging binary black holes. Credit: LIGO/A. Simonnet.

These waves are what come together to create a gravitational wave background; and while the individual events are too subtle to be detected, researchers have been attempting to develop a method for detecting the general noise for years. Relying on a combination of computer simulations of faint black hole signals and masses of data from known events, Drs. Thrane and Smith claim to have done just that.

From this, the pair were able to produce a signal within the simulated data that they believe is evidence of faint black hole mergers. Looking ahead, Drs Thrane and Smith hope to apply their new method to real data, and are optimistic it will yield results. The researchers will also have access to the new OzSTAR supercomputer, which was installed last month at the Swinburne University of Technology to help scientists to look for gravitational waves in LIGO data.

This computer is different from those used by the LIGO community, which includes the supercomputers at CalTech and MIT. Rather than relying on more traditional central processing units (CPUs), OzGrav uses graphical processor units – which can be hundreds of times faster for some applications. According to Professor Matthew Bailes, the Director of the OzGRav supercomputer:

“It is 125,000 times more powerful than the first supercomputer I built at the institution in 1998… By harnessing the power of GPUs, OzStar has the potential to make big discoveries in gravitational-wave astronomy.”

What has been especially impressive about the study of gravitational waves is how it has progressed so quickly. From the initial detection in 2015, scientists from Advanced LIGO and Virgo have now confirmed six different events and anticipate detecting many more. On top of that, astrophysicists are even coming up with ways to use gravitational waves to learn more about the astronomical phenomena that cause them.

All of this was made possible thanks to improvements in instrumentation and growing collaboration between observatories. And with more sophisticated methods designed to sift through archival data for additional signals and background noise, we stand to learn a great deal more about this mysterious cosmic force.

Further Reading: Monash, Physical Review X

Posted on by Matt Williams

The NewSpace Revolution is About to Bring us Tiny Space Telescopes we can all Control

Space Fab's Waypoint Space Telescope will be the first space telescope available to the general public. Credit: SpaceFab.US

One of the defining characteristics of the modern era of space exploration is the way the public and private aerospace companies (colloquially referred to as the NewSpace industry) and are taking part like never before. Thanks to cheaper launch services and the development of small satellites that can be built using off-the-shelf electronics (aka. CubeSats and microsats), universities and research institutions are also able to conduct research in space.

Looking to the future, there are those who want to take public involvement in space exploration to a whole new level. This includes the California-based aerospace company Space Fab that wants to make space accessible to everyone through the development the Waypoint Space Telescope – the first space telescope that people will be able to access through their smartphones to take pictures of Earth and space.

The company was founded in 2016 by Randy Chung and Sean League with the vision of creating a future where anything could be manufactured in space. Chung began his career developing communications satellites and has a background in integrated circuit design, digital signal processing, CMOS imager design, and software development. He holds sixteen patents in the fields of computer peripherals, imagers, and digital communications.

League, meanwhile, is an astrophysicist who has spent the past few decades developing optics, building and designing remote telescopes, solid state lasers, and has lots of experience with startups, fundraising, computer-aided design (CAD) and machining. Between the two of them, they are ideally suited to creating a new generation of publicly-accessible telescopes. As League told Universe Today via email:

“We have studied over 200 papers on the design of small satellite structures, electronics, navigation, and attitude control. We are rethinking satellite design, not tied down by legacy approaches. That fresh approach leads us to use a Corrected Dall Kirkham telescope design, rather than the standard Richey-Chretien design, an extending secondary mirror, rather than a fixed telescope structure, and a multi-purpose and multi-directional telescope, not a single purpose telescope just for Earth observation or just for astronomy.”

Together, League and Chung launched Space Fab in the hopes of spurring the development of the space industry, where asteroid mining and space manufacturing will provide cheap and abundant resources for all and allow for further exploration of our Solar System. The first step in this long-term plan is to build a profitable space telescope business by creating the first commercial, multipurpose space telescope industry.

“SpaceFab’s primary long term objective is to accelerate man’s access to space and to make the human race a multi-planet species,” said League. “This not only safeguards the human race, but all life that is brought along. We intend to make space resources readily available and dramatically less expensive than today, without environmental impact on Earth.”

What makes the Waypoint Space Telescope especially unique is the way it combines off-the-shelf components with revolutionary instruments. The design is based on a standard 12U CubeSat satellite, which contains the Waypoint telescope. This telescope has extendable optics that consist of a 21 cm silicon carbide primary mirror, a deployable secondary mirror, a 48 Megapixel imager for visible and near-infrared wavelengths, an 8 Megapixel image intensified camera for ultraviolet and visible wavelengths and a 150 band hyper-spectral imager.

“Waypoint’s astronomical capabilities are impressive,” says League. “Without the distorting effects of Earth’s atmosphere, our 48 megapixel imager can take perfect high resolution images every time. We can reach the maximum theoretical resolution for our main mirror at .6 arc seconds per pixel on a single image, and higher resolution is possible through multiple exposures. Contrast will be fantastic, with the blackness of background space not being washed out by Earth’s atmosphere, clouds, moisture, city lights, or the day/night cycle. The Waypoint satellite also includes a complete set of astronomical and earth observations filters.”

The Waypoint Space Telescope will be ready to launch as a secondary payload by the end of 2019 on a rocket like the SpaceX Falcon 9. The company has also completed its first seed round of investment  and is currently crowdfunding through a Kickstarter campaign.

Those who pledge their money will have the honor of getting a “space selfie”, where a favorite photo will be paired with a backdrop of Earth, pictured from orbit. In addition, Space Fab is building its own custom laser communications systems for the telescope optimized for low power, small size, and high speed.

Once deployed, this communication system will allow the telescope to download data back to Earth twice a day using optical ground stations. These images will then be available for upload via smartphone, tablet, computer or other devices. Chung and League’s efforts to create the first accessible telescope is already drawing its share of acolytes. One such person is Dustin Gibson, one of the owners of OPT Telescopes. As he told Universe Today via email:

“So far, the company is on the fast track to success with its first round of investing completed and over target, and the second round just getting started. It looks like this thing is going to fly in 2019! For an astrophotography lover like myself, I can’t think of anything more ground breaking than a consumer controlled space telescope.

“What Space Fab is doing is rewriting not just how we think about ways in which to do land surveys or deep space imaging, but actually redefining the way we are able interact with satellites by giving the common user a level of control over the movements and functionality of the unit itself with something as simple as a cell phone.”

Looking ahead, Space Fab is also busy developing the technology that will allow them to mine asteroids and tap the abundant resources of the Solar System. The company recently filed a patent for their ion accelerator, which is designed to augment the thrust from existing cubesat-sized ion engines.

The company is also focused on creating advanced robotic arms that will be able to wrestle with space debris and repair themselves in the event of mechanical failure or damage. In the meantime, the Waypoint is the first of several space telescopes that Space Fab hopes to deploy in order to generate revenue for these ventures.

“Our space telescopes will be open to everyone, so that is the beginning,” said League. “The revenue these satellites will generate provides us with the funds and knowledge base to conduct metal asteroid mining and manufacturing on a large scale. This will allow the manufacture of large structures, spacecraft, tools or anything thing else that is needed in space. With these available resources, our hope is to accelerate the space economy and colonization.”

In this respect, Space Fab is in good company when it comes to the age of NewSpace. Alongside big-names like SpaceX, Blue Origin, Planetary Resources, and Deep Space Industries, they are part of a constellation of companies that are looking to make space accessible and usher in an age of post-scarcity. And with the help of the general public, they just might succeed!

Further Reading: SpaceFab,

Posted on by Evan Gough

The Aurora Station Will be the First Luxury Hotel in Space

The Aurora Station space hotel will launch in 2021 and host its first guests in 2022. It has room for 4 guests and 2 crew. Image: Orion Span

Are you ready for a luxury hotel in space? We all knew it was coming, even though it seems impossibly futuristic. But this time it’s not just science fiction; somebody actually has a plan.

The space hotel will be called “Aurora Station” and the company behind it is Orion Span, a Silicon Valley and Houston-based firm. Orion Span aims to deliver the astronaut experience to people, by delivering the people into space. The catch?

“We developed Aurora Station to provide a turnkey destination in space. Upon launch, Aurora Station goes into service immediately, bringing travelers into space quicker and at a lower price point than ever seen before, while still providing an unforgettable experience” – Frank Bunger, CEO and founder of Orion Span.

First of all, a 12 day stay aboard Aurora Station for two people will cost $19 million US, or $9.5 million per person. Even so, you can’t just buy a ticket and hop on board. Guests must also sign up for three months of Orion Span Astronaut Certification (OSAC). Then they’ll be trained at a facility in Houston, Texas.

So once their cheque has cleared, and once they’re trained, what awaits guests on Aurora Station?

Aurora Station will orbit Earth at 320 km (200 m) and will make the trip around Earth every 90 minutes. If you do the math, that’s 16 sunrises and sunsets each day, and guests will enjoy this slideshow for 12 days. Other than this compressed schedule of 96 sunsets and 96 sunrises during their 12 day stay, guests will also be treated to stunning views of the Earth rolling by underneath them, thanks to the unprecedented number of windows Aurora Station will have.

Aurora Station will have 5600 square feet of living space which can be configured as 2 or 4 suites. Image: Orion Span

Aurora Station is the brain-child of Orion Span’s CEO, Frank Bunger. “We developed Aurora Station to provide a turnkey destination in space. Upon launch, Aurora Station goes into service immediately, bringing travelers into space quicker and at a lower price point than ever seen before, while still providing an unforgettable experience,” said Bunger.

Guests won’t be alone on the station, of course. The space hotel will have room for 6 people in total, meaning 4 guests and 2 crew. (You didn’t think you’d be alone up there, did you?) Each pair of guests will still have some alone time though, in what Orion Span calls luxurious private suites for two.

There’s no doubt that staying on a space hotel for 12 days will be the experience of a lifetime, but still, 12 days is a long time. The space station itself will be 5600 square feet, with two suites that can be configured to four. Each suite will be about the size of a small bedroom. Once you’ve gotten used to seeing Earth below you, and you’re used to your suite, what will you do?

Well, there’ll be Wi-Fi of course. So if you’re the type of person who gets bored of orbiting the only planet that we know of that hosts life, and the only planet on which every human civilization has lived and died on, you can always surf the web or watch videos. Aurora Station will also have a virtual-reality holodeck, the cherry-on-top for this science-fiction-come-to- life space resort.

But apparently, boredom won’t be a problem. In an interview with the Globe and Mail, Orion Span CEO Frank Bunger said, ““We talked to previous space tourists, they said 10 days aboard the space station was not enough.” Maybe the extra 2 days in space that Aurora Station guests will enjoy will be just the right amount.

As far as getting guests to the station, that will be up to other private space companies like SpaceX. SpaceX has plans to send tourists on trips around the Moon, and they have experience docking with the International Space Station, so they should be able to transport guests to and from a space hotel.

Aurora Station will also host micro-gravity research and in-situ manufacturing. Image: Orion Span

It doesn’t seem like there’s any shortage of customers. Aurora Station was introduced on April 5th 2018, and the first four months of reservations sold out within 72 hours, with each guest paying a deposit of $80,000 US.

There’s another side to Aurora Station, though. Other than just a nice get-away for people who can afford it, there’s a research aspect to it. Orion Span will offer Aurora Station as a platform for micro-gravity research on a pay-as-you-go basis. It will also lease capacity for in-situ manufacturing and 3D printing research.

But Aurora Station would hardly be in the news if it was only a research endeavour. What’s got people excited is the ability to visit space. And maybe to own some real estate there.

Orion Span is designing Aurora Station to be expandable. They can attach more stations to the original without disrupting anything. And this leads us to Orion Span’s next goal: space condos.

As it says on Orion Span’s website, “Like a city rising from the ground, this unique architecture enables us to build up Aurora Station in orbit dynamically – on the fly – and with no impact to the remainder of Aurora Station. As we add capacity, we will design in condos available for purchase.”

I think we all knew this would happen eventually. If you have the money, you can visit space, and even own a condo there.

No word yet on what that will cost.

Posted on by Matt Williams

Could We Detect an Ancient Industrial Civilization in the Geological Record?

Human activity is a major cause of air pollution, much of which results from industrial processes. Credit: cherwell.org

As a species, we humans tend to take it for granted that we are the only ones that live in sedentary communities, use tools, and alter our landscape to meet our needs. It is also a foregone conclusion that in the history of planet Earth, humans are the only species to develop machinery, automation, electricity, and mass communications – the hallmarks of industrial civilization.

But what if another industrial civilization existed on Earth millions of years ago? Would we be able to find evidence of it within the geological record today? By examining the impact human industrial civilization has had on Earth, a pair of researchers conducted a study that considers how such a civilization could be found and how this could have implications in the search for extra-terrestrial life.

The study, which recently appeared online under the title “The Silurian Hypothesis: Would it be possible to detect an industrial civilization in the geological record“, was conducted by Gavin A. Schmidt and Adam Frank – a climatologist with the NASA Goddard Institute for Space Studies (NASA GISS) and an astronomer from the University of Rochester, respectively.

Carbon dioxide in Earth’s atmosphere if half of global-warming emissions are not absorbed. Credit: NASA/JPL/GSFC

As they indicate in their study, the search for life on other planets has often involved looking to Earth-analogues to see what kind conditions life could exist under. However, this pursuit also entails the search for extra-terrestrial intelligence (SETI) that would be capable of communicating with us. Naturally, it is assumed that any such civilization would need to develop and industrial base first.

This, in turn, raises the question of how often an industrial civilization might develop – what Schmidt and Frank refer to as the “Silurian Hypothesis”. Naturally, this raises some complications since humanity is the only example of an industrialized species that we know of. In addition, humanity has only been an industrial civilization for the past few centuries – a mere fraction of its existence as a species and a tiny fraction of the time that complex life has existed on Earth.

For the sake of their study, the team first noted the importance of this question to the Drake Equation. To recap, this theory states that the number of civilizations (N) in our galaxy that we might be able to communicate is equal to the average rate of star formation (R*), the fraction of those stars that have planets (fp), the number of planets that can support life (ne), the number of planets that will develop life ( fl), the number of planets that will develop intelligent life (fi), the number civilizations that would develop transmission technologies (fc), and the length of time these civilizations will have to transmit signals into space (L).

This can be expressed mathematically as: N = R* x fp x ne x fl x fi x fc x L

The Drake Equation, a mathematical formula for the probability of finding life or advanced civilizations in the universe. Credit: University of Rochester

As they indicate in their study, the parameters of this equation may change thanks to the addition of the Silurian Hypothesis, as well as recent exoplanets surveys:

“If over the course of a planet’s existence, multiple industrial civilizations can arise over the span of time that life exists at all, the value of fc may in fact be greater than one. This is a particularly cogent issue in light of recent developments in astrobiology in which the first three terms, which all involve purely astronomical observations, have now been fully determined. It is now apparent that most stars harbor families of planets. Indeed, many of those planets will be in the star’s habitable zones.”

In short, thanks to improvements in instrumentation and methodology, scientists have been able to determine the rate at which stars form in our galaxy. Furthermore, recent surveys for extra-solar planets have led some astronomers to estimate that our galaxy could contains as many as 100 billion potentially-habitable planets. If evidence could be found of another civilization in Earth’s history, it would further constrain the Drake Equation.

They then address the likely geologic consequences of human industrial civilization and then compare that fingerprint to potentially similar events in the geologic record. These include the release of isotope anomalies of carbon, oxygen, hydrogen and nitrogen, which are a result of greenhouse gas emissions and nitrogen fertilizers. As they indicate in their study:

“Since the mid-18th Century, humans have released over 0.5 trillion tons of fossil carbon via the burning of coal, oil and natural gas, at a rate orders of magnitude faster than natural long-term sources or sinks. In addition, there has been widespread deforestation and addition of carbon dioxide into the air via biomass burning.”
Based on fossil records, 250 million years ago over 90% of all species on Earth died out, effectively resetting evolution. Credit: Lunar and Planetary Institute

They also consider increased rates of sediment flow in rivers and its deposition in coastal environments, as a result of agricultural processes, deforestation, and the digging of canals. The spread of domesticated animals, rodents and other small animals are also considered – as are the extinction of certain species of animals – as a direct result of industrialization and the growth of cities.

The presence of synthetic materials, plastics, and radioactive elements (caused by nuclear power or nuclear testing) will also leave a mark on the geological record – in the case of radioactive isotopes, sometimes for millions of years. Finally, they compare past extinction level events to determine how they would compare to a hypothetical event where human civilization collapsed. As they state:

“The clearest class of event with such similarities are the hyperthermals, most notably the Paleocene-Eocene Thermal Maximum (56 Ma), but this also includes smaller hyperthermal events, ocean anoxic events in the Cretaceous and Jurassic, and significant (if less well characterized) events of the Paleozoic.”

These events were specifically considered because they coincided with rises in temperatures, increases in carbon and oxygen isotopes, increased sediment, and depletions of oceanic oxygen. Events that had a very clear and distinct cause, such as the Cretaceous-Paleogene extinction event (caused by an asteroid impact and massive volcanism) or the Eocene-Oligocene boundary (the onset of Antarctic glaciation) were not considered.

Artistic rendition of the Chicxulub impactor striking ancient Earth, with Pterosaur observing. Credit: NASA

According to the team, the events they did consider (known as “hyperthermals”) show similarities to the Anthropocene fingerprint that they identified. In particular, according to research cited by the authors, the Paleocene-Eocene Thermal Maximum (PETM) shows signs that could be consistent with anthorpogenic climate change. These include:

 “[A] fascinating sequence of events lasting 100–200 kyr and involving a rapid input (in perhaps less than 5 kyr) of exogenous carbon into the system, possibly related to the intrusion of the North American Igneous Province into organic sediments. Temperatures rose 5–7?C (derived from multiple proxies), and there was a negative spike in carbon isotopes (>3%), and decreased ocean carbonate preservation in the upper ocean.”

Finally, the team addressed some possible research directions that might improve the constraints on this question. This, they claim, could consist of a “deeper exploration of elemental and compositional anomalies in extant sediments spanning previous events be performed”. In other words, the geological record for these extinction events should be examined more closely for anomalies that could be associated with industrial civilization.

If any anomalies are found, they further recommend that the fossil record could be examined for candidate species, which would raise questions about their ultimate fate. Of course, they also acknowledge that more evidence is necessary before the Silurian Hypothesis can be considered viable. For instance, many past events where abrupt Climate Change took place have been linked to changes in volcanic/tectonic activity.

Scientists were able to gauge the rate of water loss on Mars by measuring the ratio of water and HDO from today and 4.3 billion years ago. Credit: Kevin Gill

Second, there is the fact that current changes in our climate are happening faster than in any other geological period. However, this is difficult to say for certain since there are limits when it comes to the chronology of the geological record. In the end, more research will be necessary to determine how long previous extinction events (those that were not due to impacts) took as well.

Beyond Earth, this study may also have implications for the study of past life on planets like Mars and Venus. Here too, the authors suggest how explorations of both could reveal the existence of past civilizations, and maybe even bolster the possibility of finding evidence of past civilizations on Earth.

“We note here that abundant evidence exists of surface water in ancient Martian climates (3.8 Ga), and speculation that early Venus (2 Ga to 0.7 Ga) was habitable (due to a dimmer sun and lower CO2 atmosphere) has been supported by recent modeling studies,” they state. “Conceivably, deep drilling operations could be carried out on either planet in future to assess their geological history. This would constrain consideration of what the fingerprint might be of life, and even organized civilization.”
Two key aspects of the Drake Equation, which addresses the probability of finding life elsewhere in the galaxy, are the sheer number of stars and planets out there and the amount of time life has had to evolve. Until now, it has been assumed that one planet would give rise to one intelligent species capable of advanced technology and communications.
But if this number should prove to be more, we may a find a galaxy filled with civilizations, both past and present. And who knows? The remains of a once advanced and great non-human civilization may very well be right beneath us!

Further Reading: arXiv

Posted on by Susie Murph

Astronomy Cast Ep. 487: Dark Matter: 2018 Edition

Last week, we gave you an update in particle physics. This week it’s time to see what’s new in the world of dark matter. Spoiler alert, we still have no idea what it is, but maybe a few more ideas for what it isn’t.

We usually record Astronomy Cast every Friday at 3:00 pm EST / 12:00 pm PST / 20:00 PM UTC. You can watch us live on AstronomyCast.com, or the AstronomyCast YouTube page.

Visit the Astronomy Cast Page to subscribe to the audio podcast!

If you would like to support Astronomy Cast, please visit our page at Patreon here – https://www.patreon.com/astronomycast. We greatly appreciate your support!

If you would like to join the Weekly Space Hangout Crew, visit their site here and sign up. They’re a great team who can help you join our online discussions!

Posted on by Evan Gough

Look at This Fascinating Variety of Planet-Forming Disks Around Other Stars

This is just one of the spectacular images of dusky discs from the SPHERE instrument on ESO's Very Large Telescope. It shows the disc around the young star IM Lupi in finer detail than ever before. The collection of images shows the fascinating variety of shapes and sizes of discs. Image: ESO/H. Avenhaus et al./DARTT-S collaboration

The European Southern Observatory (ESO) has released a stunning collection of images of the circumstellar discs that surround young stars. The images were captured with the SPHERE (Spectro-Polarimetric High-contrast Exoplanet REsearch) instrument on the ESO’s Very Large Telescope (VLT) in Chile. We’ve been looking at images of circumstellar disks for quite some time, but this collection reveals the fascinating variety of shapes an sizes that these disks can take.

New images from the SPHERE instrument on ESO’s Very Large Telescope are revealing the dusty discs surrounding nearby young stars in greater detail than previously achieved. They show a bizarre variety of shapes, sizes and structures, including the likely effects of planets still in the process of forming. Image: ESO/H. Avenhaus et al./E. Sissa et al./DARTT-S and SHINE collaborations

We have a widely-accepted model of star formation supported by ample evidence, including images like these ones from the ESO. The model starts with a cloud of gas and dust called a giant molecular cloud. Within that cloud, a pocket of gas and dust begins to coalesce. Eventually, as gravity causes material to fall inward, the pocket becomes more massive, and exerts even more gravitational pull. More gas and dust continues to be drawn in.

The material that falls in also gives some angular momentum to the pocket, which causes rotation. Once enough material is accumulated, fusion ignites and a star is born. At that point, there is a proto-star inside the cloud, with unused gas and dust remaining in a rotating ring around the proto-star. That left over rotating ring is called a circumstellar disc, out of which planets eventually form.

There are other images of circumstellar discs, but they’ve been challenging to capture. To image any amount of detail in the disks requires blocking out the light of the star at the center of the disk. That’s where SPHERE comes in.

A detailed view of the SPHERE instrument and its main subsystems. SPHERE is installed on the ESO’s VLT and saw first light in 2014. Image: ESO

SPHERE was added to the ESO’s Very Large Telescope in 2014. It’s primary job is to directly image exoplanets, but it also has the ability to capture images of circumstellar discs. To do that, it separates two types of light: polarized, and non-polarized.

Light coming directly from a star—in these images, a young star still surrounded by a circumstellar disc—is non-polarized. But once that starlight is scattered by the material in the disk itself, the light becomes polarized. SPHERE, as its name suggests, is able to separate the two types of light and isolate just the light from the disk. That is how the instrument captures such fascinating images of the disks.

An edge-on view of the disc surrounding the star GSC 07396-00759. The disc extends from the lower-left to the upper-right and the central grey region shows where the star was masked out. Credit:
ESO/E. Sissa et al.

Ever since it became clear that exoplanets are not rare, and that most stars—maybe all stars—have planets orbiting them, understanding solar system formation has become a hot topic. The problem has been that we can’t really see it happening in real time. We can look at our own Solar System, and other fully formed ones, and make guesses about how they formed. But planet formation is hidden inside those circumstellar disss. Seeing into those disks is crucial to understanding the link between the properties of the disk itself and the planets that form in the system.

The discs imaged in this collection are mostly from a study called the DARTTS-S (Discs ARound T Tauri Stars with SPHERE) survey. T Tauri stars are young stars less than 10 million years old. At that age, planets are still in the process of forming. The stars range from 230 to 550 light-years away from Earth. In astronomical terms, that’s pretty close. But the blinding bright light of the stars still makes it very difficult to capture the faint light of the discs.

One of the images is not a T Tauri star and is not from the DARTTS-S study. The disc around the star GSC 07396-00759, in the image above, is actually from the SHINE (SpHere INfrared survey for Exoplanets) survey, though the images itself was captured with SPHERE. GSC 07396-00759 is a red star that’s part of a multiple star system that was part of the DARTTS-S study. The puzzling thing is that red star is the same age as the T TAURI star in the same system, but the ring around the red star is much more evolved. Why the two discs around two stars the same age are so different from each other in terms of time-scale and evolution is a puzzle, and is one of the reasons why astronomers want to study these discs much more closely.

We can study our own Solar System, and look at the positions and characteristics of the planets and the asteroid belt and Kuiper Belt. From that we can try to guess how it all formed, but our only chance to understand how it all came together is to look at other younger solar systems as they form.

The SPHERE instrument, and other future instruments like the James Webb Space Telescope, will allow us to look into the circumstellar discs around other stars, and to tease out the details of planetary formation. These new images from SPHERE are a tantalizing taste of the detail and variety we can expect to see.

Posted on by Matt Williams

Pluto’s Charon Gets Mountains Named After Sci-Fi Authors Octavia Butler and Arthur C. Clarke, as Well as Many Others From History and Legend. I Approve!

Map projection of Charon, the largest of Pluto’s five moons, annotated with its first set of official feature names. With a diameter of about 1215 km, the France-sized moon is one of largest known objects in the Kuiper Belt, the region of icy, rocky bodies beyond Neptune. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

In 2015, the New Horizons mission made history by being the first spacecraft to conduct a flyby of Pluto. In addition to revealing things about the planet’s atmosphere, its geology and system of moons, the probe also provided the first clear images of the surface of Pluto and its largest moon, Charon. Because of this, scientists are now able to study Pluto and Charon’s many curious surface features and learn more about their evolution.

Another interesting thing that has resulted from this surface imaging has been the ability to name these features. Recently, the IAU Working Group for Planetary System Nomenclature officially approved of a dozen names that had been proposed by NASA’s New Horizons team. These names honor legendary explorers and visionaries, both real and fictitious, and include science fiction authors Octavia Butler and Arthur C. Clarke.

Aside from being Pluto’s largest moon, Charon is also one of the larger bodies in the Kuiper Belt. Because of its immense size, Charon does not orbit Pluto in the strictest sense. In truth, the barycenter of the Pluto-Charon system is outside Pluto, meaning the two bodies almost orbit each other. The moon also has a wealth of features, which include valleys, crevices, and craters similar to what have been seen on other moons.

Artist’s impression of New Horizons’ close encounter with the Pluto–Charon system. Credit: NASA/JHU APL/SwRI/Steve Gribben

For some time, the New Horizons team has been using a series of informal names to describe Charon’s many features. The team gathered most of them during the online public naming campaign they hosted in 2015. Known as  “Our Pluto“, this campaign consisted of people from all over the world contributed their suggestions for naming features on Pluto and Charon.

The New Horizons team also contributed their own suggestions and (according to the IAU) was instrumental in moving the new names through approval. As Dr. Alan Stern, the New Horizon team leader, told Universe Today via email: “We conduced a public feature name bank process in 2015 before flyby. Once flyby was complete our science team created a naming proposal for specific features and sent it to IAU.”

A similar process took place last year, where the IAU officially adopted 14 place names that were suggested by the New Horizons team – many of which were the result of the online naming campaign. Here too, the names were those that the team had been using informally to describe the many regions, mountain ranges, plains, valleys and craters that were discovered during the spacecraft’s flyby.

The names that were ultimately selected honored the spirit of epic exploration, which the New Horizons mission demonstrated by being the first probe to reach Pluto. As such, the names that were adopted honored travelers, explorers, scientists, pioneering journeys, and mysterious destinations. For example, Butler Mons honors Octavia E. Butler, a celebrated author and the first science fiction writer to win a MacArthur fellowship.

Global map of Pluto’s moon Charon pieced together from images taken at different resolutions. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Similarly, Clarke Montes honors Sir Arthur C. Clarke, the prolific writer and futurist who co-wrote the screenplay for 2001: A Space Odyssey (which he later turned into a series of novels). Stanley Kubrik, who produced and directed 2001: A Space Odyssey, was also honored with the feature Kubrik Mons. Meanwhile, several craters were named in honor of fictional characters from famous stories and folklore.

The Revati Crater is named after the main character in the Hindu epic narrative Mahabharata while the Nasreddin Crater is named for the protagonist in thousands of folktales told throughout the Middle East, southern Europe and parts of Asia. Nemo Crater honors the captain of the Nautilus in Jule’s Verne’s novels Twenty Thousand Leagues Under the Sea (1870) and The Mysterious Island (1874).

The Pirx Crater is name after the main character in a series of short stories by Polish sci-fi author Stanislaw Lem, while the Dorothy Crater takes its name from the protagonist in The Wizard of Oz, one of several children’s stories by L. Frank Baum that was set in this magical land.

As Rita Schulz, chair of the IAU Working Group for Planetary System Nomenclature, commented, “I am pleased that the features on Charon have been named with international spirit.” Dr. Alan Stern expressed similar sentiments. When asked if he was happy with the new names that have been approved, he said simply, “Very.”

Artist’s impression of NASA’s New Horizons spacecraft encountering 2014 MU69 (Ultima Thule), a Kuiper Belt object that orbits 1.6 billion km (1 billion mi) beyond Pluto, on Jan. 1st, 2019. Credits: NASA/JHUAPL/SwRI/Steve Gribben

Even though the encounter with the Pluto system happened almost three years ago, scientists are still busy studying all the information gathered during the historic flyby. In addition, the New Horizons spacecraft will be making history again in the not-too-distant future. At present, the spacecraft is making its way farther into the outer Solar System with the intention of rendezvousing with two Kuiper Belt Objects.

On Jan. 1st, 2019, it will rendezvous with its first destination, the KBO known as 2014 MU69 (aka. “Ultima Thule“). This object will be the most primitive object ever observed by a spacecraft, and the encounter will the farthest ever achieved in space exploration. Before this intrepid exploration mission is complete, we can expect that a lot more of the outer Solar System will be mapped and named.

Further Reading: IAU