Universe Today

April 10, 2018February 7, 2021 by Matt Williams

Proxima Centauri Just Released a Flare so Powerful it was Visible to the Unaided Eye. Planets There Would Get Scorched

Artist's impression of a flaring red dwarf star, orbited by an exoplanet. Credit: NASA, ESA, and G. Bacon (STScI)

Since its discovery was announced in August of 2016, Proxima b has been an endless source of wonder and the target of many scientific studies. In addition to being the closest extra-solar planet to our Solar System, this terrestrial planet also orbits within Proxima Centauri’s circumstellar habitable zone (aka. “Goldilocks Zone”). As a result, scientists have naturally sought to determine if this planet could actually be home to extra-terrestial life.

Many of these studies have been focused on whether or not Proxima b could retain an atmosphere and liquid water on its surface in light of the fact that it orbits an M-type (red dwarf) star. Unfortunately, many of these studies have revealed that this is not likely due to flare activity. According to a new study by an international team of scientists, Proxima Centauri released a superflare that was so powerful, it would have been lethal to any life as we know it.

The study, titled “The First Naked-Eye Superflare Detected from Proxima Centauri“, recently appeared online. The team was led by Howard Ward, a PhD candidate in physics and astronomy at the UNC Chapel Hill, with additional members from the NASA Goddard Space Flight Center, the University of Washington, the University of Colorado, the University of Barcelona and the School of Earth and Space Exploration at Arizona State University.

Artist impression of a red dwarf star like Proxima Centauri, the nearest star to our sun. New analysis of ALMA observations reveal that Proxima Centauri emitted a powerful flare that would have created inhospitable conditions for planets in that system. Credit: NRAO/AUI/NSF; D. Berry

As they indicate in their study, solar flare activity would be one of the greatest potential threats to planetary habitability in a system like Proxima Centauri. As they explain:

“[W]hile ozone in an Earth-like planet’s atmosphere can shield the planet from the intense UV flux associated with a single superflare, the atmospheric ozone recovery time after a superflare is on the order of years. A sufficiently high flare rate can therefore permanently prevent the formation of a protective ozone layer, leading to UV radiation levels on the surface which are beyond what some of the hardiest-known organisms can survive.”

In addition stellar flares, quiescent X-ray emissions and UV flux from a red dwarf star can would be capable of stripping planetary atmospheres over the course of several billion years. And while multiple studies have been conducted that have explored low- and moderate-energy flare events on Proxima, only one high-energy event has even been observed.

This occurred on March of 2016, when Proxima Centauri emitted a superflare that was so bright, it was visible to the naked eye. This flare was observed by the Evryscope, an array of telescopes – funded through the National Science Foundation‘s Advanced Technologies and Instrumentation (ATI) and Faculty Early Career Development (CAREER) programs – that is pointed at every part of the accessible sky simultaneously and continuously.

*Artist’s impression of Proxima b, which was discovered using the Radial Velocity method. Credit: ESO/M. Kornmesser*

As the team indicates in their study, the March 2016 superflare was the first to be observered from Proxima Centauri, and was rather powerful:

“In March 2016 the Evryscope detected the first-known Proxima superflare. The superflare had a bolometric energy of 10^33.5 erg, ~10× larger than any previously-detected flare from Proxima, and 30×larger than any optically measured Proxima flare. The event briefly increased Proxima’s visible-light emission by a factor of 38× averaged over the Evryscope’s 2-minute cadence, or ~68× at the cadence of the human eye. Although no M-dwarfs are usually visible to the naked-eye, Proxima briefly became a magnitude-6.8 star during this superflare, visible to dark-site naked-eye observers.”

The superflare coincided with the three-month Pale Red Dot campaign, which was responsible for first revealing the existence of Proxima b. While monitoring the star with the HARPS spectrograph – which is part of the 3.6 m telescope at the ESO’s La Silla Observatory in Chile – the campaign team also obtaining spectra on March 18th, 08:59 UT (just 27 minutes after the flare peaked at 08:32 UT).

The team also noted that over the last two years, the Evryscope has recorded 23 other large Proxima flares, ranging in energy from 10^30.6 erg to 10^32.4 erg. Coupled with rates of a single superflare detection, they predict that at least five superflares occur each year. They then combined this data with the high-resolution HARPS spectroscopy to constrain the superflare’s UV spectrum and any associated coronal mass ejections.

*The Red Dots project is successor to the Pale Red Dot project, which discovered Proxima b last summer. Credit: ESO*

The team then used the HARPS spectra and the Evryscope flare rates to create a model to determine what effects this star would have on a nitrogen-oxygen atmosphere. This included how long the planet’s protective ozone layer would be able to withstand the blasts, and what effect regular exposure to radiation would have on terrestrial organisms.

“[T]he repeated flaring is sufficient to reduce the ozone of an Earth-like atmosphere by 90% within five years. We estimate complete depletion occurs within several hundred kyr. The UV light produced by the Evryscope superflare therefore reached the surface with ~100× the intensity required to kill simple UV-hardy microorganisms, suggesting that life would struggle to survive in the areas of Proxima b exposed to these flares.”

Essentially, this and other studies have concluded that any planets orbiting Proxima Centauri would not be habitable for very long, and likely became lifeless balls of rock a long time ago. But beyond our closest neighboring star system, this study also has implications for other M-type star systems. As they explain, red dwarf stars are the most common in our galaxy – roughly 75% of the population – and two-thirds of these stars experience active flare activity.

As such, measuring the impact that superflares have on these worlds will be a necessary component to determining whether or not exoplanets found by future missions are habitable. Looking ahead, the team hopes to use the Evryscope to examine other star systems, particularly those that are targets for the upcoming Transiting Exoplanet Survey Satellite (TESS) mission.

Artist’s impression of the surface of the planet Proxima b orbiting the red dwarf star Proxima Centauri. The double star Alpha Centauri AB is visible to the upper right of Proxima itself. Credit: ESO

“Beyond Proxima, Evryscope has already performed similar long-term high-cadence monitoring of every other Southern TESS planet-search target, and will therefore be able to measure the habitability impact of stellar activity for all Southern planetsearch-target M-dwarfs,” they write. “In conjunction with coronal-mass-ejection searches from long- wavelength radio arrays like the [Long Wavelength Array], the Evryscope will constrain the long-term atmospheric effects of this extreme stellar activity.”

For those who hoped that humanity might find evidence of extra-terrestrial life in their lifetimes, this latest study is certainly a letdown. It’s also disappointing considering that in addition to being the most common type of star in the Universe, some research indicates that red dwarf stars may be the most likely place to find terrestrial planets. However, even if two-thirds of these stars are active, that still leaves us with billions of possibilities.

It is also important to note that these studies help ensure that we can determine which exoplanets are potentially habitable with greater accuracy. In the end, that will be the most important factor when it comes time to decide which of these systems we might try to explore directly. And if this news has got you down, just remember the worlds of the immortal Carl Sagan:

“The universe is a pretty big place. If it’s just us, seems like an awful waste of space.”

Further Reading: arXiv

April 10, 2018 by Fraser Cain

What If New York City Had No Light Pollution?

A view of NYC with the Milky Way restored. Image Credit: Harun Mehmedinovic & Gavin Heffernan

I grew up on a small island off the West Coast of Canada, with the darkest skies you could hope for. Although I live in a small town now, with some light pollution, I can still see the Milky Way from my backyard.

But for the people living in some of the biggest cities in the world, like New York City, the sky is so much worse – the light pollution is ever present. You can see the few brightest stars and some of the planets, but mostly the sky is just a dull yellow glowing mess. And that’s a shame that so much of the world is cut off from the incredible night sky that inspires our curiosity to explore the Universe.

Gavin Heffernan and Harun Mehmedinovic from the SKYGLOW project are working to give people living under constant light pollution a sense of what it looks like to live in a world where they could actually see the Milky Way every night. And their latest video shows this perspective from a view in New York City.

The team carefully matched up timelapse video of New York City with the pristine night skies of the Grand Canyon and Death Valley International Dark-Sky Parks.

For most of the world, light pollution is an ongoing and growing concern, and the International Dark Sky Association is taking the week of April 15-21 to celebrate the night sky. They’ve got ways you can take action to push back against light pollution.

During this week, and really any time, I highly recommend you use a tool like the Dark Sky Finder to search for areas near you that’ll have the least amount of light pollution. Even folks in New York City can drive for a couple of hours to some relatively dark skies and appreciate the night sky as it was meant to be seen.

Source: SKYGLOW Project

April 9, 2018April 9, 2018 by Fraser Cain

This is the COOLEST! Everything that’s Orbiting the Earth Right Now

Stuff in Space. This is everything that's orbiting the Earth right now. Credit: James Yoder

Okay, if you’ve got some spare time, check out this amazing website called Stuff in Space. It’s a simulation of every satellite (alive or dead), space station, and large piece of space junk orbiting the Earth right now.

You can zoom in and out, rotate the Earth and its satellites around. Pick any one object and discover more information about it. Or just leave it running and watch all the objects buzz around in real time. Humans have been busy launching a lot of stuff, and it’s only going to increase.

The simulation was made by James Yoder, an incoming Electrical and Computer Engineering freshman at the University of Texas at Austin, and it’s based on data supplied by Space Track, which is a service of the Joint Space Operations Center. They have a bunch of handy data feeds and APIs that you can use track orbital objects, but I’ve never seen anything as creative as this.

Credit: Stuff in Space

April 9, 2018 by Matt Williams

A Magnetar Just Woke Up After Three Years of Silence

Aerial image of the South African MeerKAT radio telescope, part of the Square Kilometer Array (SKA). Credit: SKA

When stars reach the end of their main sequence, they undergo a gravitational collapse, ejecting their outermost layers in a supernova explosion. What remains afterward is a dense, spinning core primarily made up of neutrons (aka. a neutron star), of which only 3000 are known to exist in the Milky Way Galaxy. An even rarer subset of neutron stars are magnetars, only two dozen of which are known in our galaxy.

These stars are especially mysterious, having extremely powerful magnetic fields that are almost powerful enough to rip them apart. And thanks to a new study by a team of international astronomers, it seems the mystery of these stars has only deepened further. Using data from a series of radio and x-ray observatories, the team observed a magnetar last year that had been dormant for about three years, and is now behaving somewhat differently.

The study, titled “Revival of the Magnetar PSR J1622–4950: Observations with MeerKAT, Parkes, XMM-Newton, Swift, Chandra, and NuSTAR“, recently appeared in The Astrophysical Journal. The team was led by Dr Fernando Camilo – the Chief Scientist at the South African Radio Astronomy Observatory (SARAO) – and included over 200 members from multiple universities and research institutions from around the world.

Magnetars are so-named because their magnetic fields are up to 1000 times stronger than those of ordinary pulsating neutron stars (aka. pulsars). The energy associated with these these fields is so powerful that it almost breaks the star apart, causing them to be unstable and display great variability in terms of their physical properties and electromagnetic emissions.

Whereas all magnetars are known to emit X-rays, only four have been known to emit radio waves. One of these is PSR J1622-4950 – a magnetar located about 30,000 light years from Earth. As of early 2015, this magnetar had been in a dormant state. But as the team indicated in their study, astronomers using the CSIRO Parkes Radio Telescope in Australia noted that it was becoming active again on April 26th, 2017.

At the time, the magnetar was emitting bright radio pulses every four seconds. A few days later, Parkes was shut down as part of a month-long planned maintenance routine. At about the same time, South Africa’s MeerKAT radio telescope began monitoring the star, despite the fact that it was still under construction and only 16 of its 64 radio dishes were available. Dr Fernando Camilo describes the discovery in a recent SKA South Africa press release:

“[T]he MeerKAT observations proved critical to make sense of the few X-ray photons we captured with NASA’s orbiting telescopes – for the first time X-ray pulses have been detected from this star, every 4 seconds. Put together, the observations reported today help us to develop a better picture of the behaviour of matter in unbelievably extreme physical conditions, completely unlike any that can be experienced on Earth”.

*Artist’s rendering of an outburst on an ultra-magnetic neutron star, also called a magnetar. Credit: NASA/Goddard Space Flight Center*

After the initial observations were made by the Parkes and MeerKAT observatories, follow-up observations were conducted using the XMM-Newton x-ray space observatory, Swift Gamma-Ray Burst Mission, the Chandra X-ray Observatory, and the Nuclear Spectroscopic Telescope Array (NuSTAR). With these combined observations, the team noted some very interesting things about this magnetar.

For one, they determined that PSR J1622-4950’s radio flux density, while variable, was approximately 100 times greater than it was during its dormant state. In addition, the x-ray flux was at least 800 times larger one month after reactivation, but began decaying exponentially over the course of a 92 to 130 day period. However, the radio observations noted something in the magnetar’s behavior that was quite unexpected.

While the overall geometry that was inferred from PSR J1622-4950’s radio emissions was consistent with what had been determined several years prior, their observations indicated that the radio emissions were now coming from a different location in the magnetosphere. This above all indicates how radio emissions from magnetars could differ from ordinary pulsars.

This discovery has also validated the MeerKAT Observatory as a world-class research instrument. This observatory is part of the Square Kilometer Array (SKA), the multi-radio telescope project that is building the world’s largest radio telescope in Australia, New Zealand, and South Africa. For its part, MeerKAT uses 64 radio antennas to gather radio images of the Universe to help astronomers understand how galaxies have evolved over time.

*Aerial image of the South African MeerKAT radio telescope in the Karoo, South Africa. Credit: SKA*

Given the sheer volume of data collected by these telescopes, MeerKAT relies on both cutting edge-technology and a highly-qualified team of operators. As Abbott indicated, “we have a team of the brightest engineers and scientists in South Africa and the world working on the project, because the problems that we need to solve are extremely challenging, and attract the best”.

Prof Phil Diamond, the Director-General of the SKA Organization leading the development of the Square Kilometer Array, was also impressed by the contribution of the MeerKAT team. As he stated in an SKA press release:

“Well done to my colleagues in South Africa for this outstanding achievement. Building such telescopes is extremely difficult, and this publication shows that MeerKAT is becoming ready for business. As one of the SKA precursor telescopes, this bodes well for the SKA. MeerKAT will eventually be integrated into Phase 1 of SKA-mid telescope bringing the total dishes at our disposal to 197, creating the most powerful radio telescope on the planet”.

When the SKA goes online, it will be one of the most powerful ground-based telescopes in the world and roughly 50 times more sensitive than any other radio instrument. Along with other next-generation ground-based and space-telescopes, the things it will reveal about our Universe and how it evolved over time are expected to be truly groundbreaking.

Further Reading: SKA Africa, SKA, The Astrophysical Journal

April 9, 2018May 16, 2018 by Susie Murph

Astronomy Cast Ep. 486: Particle Physics Update

It’s time for a news update. This time from the field of particle physics. It turns out there have been all kinds of new and interesting particles discovered by the Large Hadron Collider and others. Let’s get an update from Pamela.

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.

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April 9, 2018 by Evan Gough

Launching Rockets from Balloons is About to be a Thing, But We Need a Better Name than “Rockoons”

Leo Aerospace plans to use “rockoons” (high-altitude balloons) that left rockets about 11 miles (18 kilometers) above Earth, where there is 95 percent less atmosphere to cause drag. That makes the rockoon less expensive to launch than a traditional rocket. The system works only for microsatellites. Image: Leo Aerospace.

One of the technological hurdles of our age is to get people and equipment into space more cheaply. SpaceX gets a lot of the headlines around that, with their reusable rockets. And so does Blue Origin, to some degree. Now a small start-up affiliated with Purdue University is tackling the problem and making some headway.

The company is called Leo Aerospace LLC and they’re using balloons to lower the cost of putting micro-satellites into orbit, rather than reusable rockets. The balloons will be reusable, but the rockets won’t.

Leo Aerospace plans to revive a decades-old method of putting satellites into space. They’re using hot air balloons to lift the rocket and its micro-satellite payload 18 km (11 miles) above Earth. At that altitude, there’s 95% less atmosphere. This means much less drag on the rocket, which translates into smaller rockets with less fuel. This is an intriguing idea, if not for the unfortunate name.

The rockoons will be used to launch rockets into sub-orbital and orbital flights. Sub-orbitals are often used by researchers because it gives them access to zero gravity and to vacuum, both of which are necessary for some experiments. According to Leo Aerospace, there’s something revolutionary about their plans.

“We’re targeting the microsatellites by saying, ‘You don’t have to ride-share with anyone. We can guarantee you will be our only payload and we will be focused on you.’” – Drew Sherman, Leo Aerospace’s Head of Vehicle Development.

They intend on targeting micro-satellite developers. Micro-satellites are often hitch-hikers on larger payloads, which basically means they’re second-class customers. They have to wait until there’s room for their micro-satellite on a traditional rocket carrying a larger payload. This can mean long delays of several months, and that micro-satellite developers have to compromise when it comes to the orbits they can obtain. It can also make micro-satellite missions difficult to plan and execute efficiently and economically. Micro-satellites are becoming more and more capable, so having a launch system tailor-made for them could indeed be revolutionary.

“We’re targeting the microsatellites by saying, ‘You don’t have to ride-share with anyone. We can guarantee you will be our only payload and we will be focused on you,’” said Drew Sherman, Leo Aerospace’s head of vehicle development. “‘We will work with you exclusively to get you into orbit. You won’t have to worry about other payloads or getting dropped off in the wrong spot.’”

The flexibility of the rockoon system that Leo Aerospace is developing will be intriguing for micro-satellites. Rockoons will give micro-satellites the flexibility they need to operate efficiently. The launch can be scheduled and adapted to the needs of the individual satellite. “Our goal is to give people access to space. The only way to do that right now is to help people get their satellite into orbit. That’s where we want to leave our mark,” said Abishek Murali, Head of Mission Engineering at Leo Aerospace.

“Our goal is to give people access to space.” – Abishek Murali, Head of Mission Engineering at Leo Aerospace

The rockoon itself is a hybrid of a balloon and a rocket. The hybrid design takes advantage of physics by using the balloon to float the rocket 18 km high before launching the rocket. The rockoon has Leo Aerospace’s own patent-pending technology to control the pitch and angle of the launch, allowing for precision launches.

Rockoons were first used by the US Air Force back in the 1950s. But this next generation of rockoons, coupled with modern micro-satellites, will be much more capable than the 1950s technology.

Leo Aerospace LLC was started by five then-Purdue University students as a club and then turned into a business. The founders are, from left, Mike Hepfer, head of product development; Drew Sherman, head of vehicle development; Abishek Murali, head of mission engineering; Dane Rudy; chief executive officer; and Bryce Prior, head of operations and strategy. Image: Leo Aerospace.

Currently, Leo Aerospace is in the development and funding phase. They’ve obtained some funding from the National Science Foundation, and from a venture capital firm. They have about half of the $250,000 they need. They plan to conduct their first sub-orbital flight in 2020, and to launch their first micro-satellite into orbit in 2022. They intend to use existing approved launch sites.

Leo Aerospace was founded by five then-students at Purdue University. Leo started as a club, but the former students have turned it into a business. And that business seems to have a bright future. They conducted a customer discovery and market validation study and found a large demand for a better way to launch micro-satellites.

“We want to be part of the space market,” Murali said. “People are interested in space and creating technologies that not only can operate in space but also help people back on Earth. What we’re trying to do is help them get there.”

But they still need a better name than “rockoons.”

April 9, 2018 by Matt Williams

Astronomers Just Found 72 Stellar Explosions, but Don’t Know What’s Causing Them

Images of one of the transient events, from eight days before the maximum brightness to 18 days afterwards. This outburst took place at a distance of 4 billion light years. Credit: M. Pursiainen / University of Southampton and DES collaboration

A supernova is one of the most impressive natural phenomena in the Universe. Unfortunately, such events are often brief and transient, temporarily becoming as bright as an entire galaxy and then fading away. But given what these bright explosions – which occur when a star reaches the end of its life cycle – can teach us about the Universe, scientists are naturally very interested in studying them.

Using data from the Dark Energy Survey Supernova (DES-SN) program, a team of astronomers recently detected 72 supernovae, the largest number of events discovered to date. These supernovae were not only very bright, but also very brief – a finding which the team is still struggling to explain. The results of their study were presented on Tuesday, April 3rd, at the European Week of Astronomy and Space Science in Liverpool.

The team was led by Miika Pursiainen, a PhD researcher from the University of Southampton. For the sake of their study, the team relied on data from the 4-meter telescope at the Cerro Tololo Inter-American Observatory (CTIO). This telescope is part of the Dark Energy Survey, a global effort to map hundreds of millions of galaxies and thousands of supernovae in to find patterns int he cosmic structure that will reveal the nature of dark energy.

*This image shows the incredibly distant and ancient supernova DES16C2nm. The supernova was discovered by the Dark Energy Survey. Image: Mat Smith and DES collaboration.*

As Pursiainen commented in a recent Southampton news release:

“The DES-SN survey is there to help us understand dark energy, itself entirely unexplained. That survey then also reveals many more unexplained transients than seen before. If nothing else, our work confirms that astrophysics and cosmology are still sciences with a lot of unanswered questions!”

As noted, these events were very peculiar in that they had a similar maximum brightness compared to different types of supernove, they were visible for far less time. Whereas supernova typically last for several months or more, these transient supernovae were visible for about a week to a month. The events also appeared to be very hot, with temperatures ranging from 10,000 to 30,000 °C (18,000 to 54,000 °F).

They also vary considerably in size, ranging from being several times the distance between the Earth and the Sun – 150 million km, 93 million mi (or 1 AU) – to hundreds of times. However, they also appear to be expanding and cooling over time, which is what is expected from an event like a supernova. Because of this, there is much debate about the origin of these transient supernovae.

*Artistic impression of a star going supernova, casting its chemically enriched contents into the universe. Credit: NASA/Swift/Skyworks Digital/Dana Berry*

A possible explanation is that these stars shed a lot of material before they exploded, and that this could have shrouded them in matter. This material may then have been heated by the supernovae themselves, causing it to rise to very high temperatures. This would mean that in these cases, the team was seeing the hot clouds rather than the exploding stars themselves.

This certainly would explain the observations made by Pursiainen and his team, though a lot more data will be needed to confirm this. In the future, the team hopes to examine more transients and see how often they occur compared to more common supernovae. The study of this powerful and mysterious phenomenon will also benefit from the use of next-generation telescopes.

When the James Webb Space Telescope is deployed in 2020, it will study the most distant supernovae in the Universe. This information, as well as studies performed by ground-based observatories, is expected to not only shed light on the life cycle of stars and dark energy, but also on the formation of black holes and gravitational waves.

Further Reading: University of Southampton

April 6, 2018April 8, 2018 by Matt Williams

NASA Begins Construction of its New Quiet Supersonic Plane

An artist’s concept of the low-boom flight demonstrator outside the Lockheed Martin Aeronautics Company’s Skunk Works hangar in Palmdale, California. Credits: Lockheed Martin

NASA has a lot of experience when it comes to developing supersonic aircraft. In fact, testing supersonic craft was how NASA got its start, back when it still known as the National Advisory Committee for Aeronautics (NACA). Beginning with the Bell X-1, the tradition of using X-planes and other experimental aircraft continues, and has progressed to hypersonic scramjets and spaceplanes (like the X-37).

And now, for the first time in decades, NASA is looking to develop a new supersonic aircraft. But whereas previous aircraft were developed for the sake of breaking speed records, the purpose of this latest X-plane is to create a Quiet Supersonic Transport (QueSST). NASA hopes that this craft will provide crucial data that could enable the development of commercial supersonic air travel over land.

To that end, NASA awarded a $247.5 million contract to Lockheed Martin Aeronautics Company on April 2nd to build the X-plane and deliver it to the agency’s Armstrong Flight Research Center in California by the end of 2021. As Jaiwon Shin, NASA’s associate administrator for aeronautics, indicated in a recent NASA press release, this project is like revisiting the old days of NASA research.

Shock diamonds in Chuck Yeager's X-1 — *The Bell X-1, in which Chuck Yeager “broke” the sound barrier in 1947. Credit: NASA*

“It is super exciting to be back designing and flying X-planes at this scale,” he said. “Our long tradition of solving the technical barriers of supersonic flight to benefit everyone continues.”

In the past, supersonic commercial flights were available, for people who could afford them at least. These included the British-French Concorde (which operated until 2003) and the Russian Tupolev Tu-144 (retired in 1983). However, these craft were incapable of conducting supersonic flights over land because of how breaking the sound barrier would generate a sonic boom – which are extremely loud and potentially harmful.

As a result, current Federal Aviation Administration (FAA) regulations ban supersonic flight over land. The purpose of this latest aircraft – known as the Low-Boom Flight Demonstrator – is to conduct supersonic flights that create sonic booms that are so quiet, they will be virtually unnoticeable to people on the ground. The key is how the X-plane’s uniquely-shaped hull generates supersonic shockwaves.

With conventional aircraft designs, shockwaves coalesce as they expand away from the airplane’s nose and tail, resulting in two distinct sonic booms. In contrast, the X-plane’s hull design sends shockwaves away from the aircraft in a way that prevents them from coming together. Instead, much weaker shockwaves are sent to the ground that would be heard as a series of soft thumps.

This modified Northrop F-5E jet was used during 2003 for NASA’s Shaped Sonic Boom Demonstration program, a successful effort to show that an aircraft’s shape can be used to reduce the intensity of the sonic booms it creates while flying supersonic. Credits: NASA

Since the 1960s, NASA has been testing the idea using vehicles like the F-5E Tiger II fighter jet. This aircraft, which flew test flights in 2003-2004 as part of NASA’s Shaped Sonic Boom Demonstration program, had a uniquely-shaped nose and demonstrated that boom-reducing theory was sound. More recent flight testing, wind-tunnel testings, and advanced computer simulations tools have also indicated that the technology will work.

As Peter Coen, NASA’s Commercial Supersonic Technology project manager, stated:

“We’ve reached this important milestone only because of the work NASA has led with its many partners from other government agencies, the aerospace industry and forward-thinking academic institutions everywhere.”

The X-plane’s configuration will be based on a QueSST design that Lockheed Martin developed in 2016 in partnership with NASA, and which completed testing in a wind tunnel at NASA’s Glenn Research Center in 2017 . The proposed aircraft will measure 28.65 meters (94 feet) long, have a wingspan of about 9 meters (29.5 feet), and have a takeoff weight of 14,650 kg (32,300 lbs).

Based on the company’s design, the X-plane will be powered by a single General Electric F414 engine, the same used by F/A-18E/F fighters. It will be flown by a single pilot and have a top speed of Mach 1.5 (1590 km; 990 mph) and a speed of Mach 1.42 (1513 km; 940 mph) at a cruising altitude of 16764 meters (55,000 feet).

*Illustration of NASA’s planned Low Boom Flight Demonstration aircraft as outlined during the project’s Preliminary Design Review last week. Credits: NASA / Lockheed Martin*

As Shin indicated, the development of the X-plan is a joint effort involving all of NASA’s aeronautics research centers:

“There are so many people at NASA who have put in their very best efforts to get us to this point. Thanks to their work so far and the work to come, we will be able to use this X-plane to generate the scientifically collected community response data critical to changing the current rules to transforming aviation!”

The program is divided into three phases which are tentatively scheduled to run from 2019 to 2025. Phase One, which will run from 2019 to 2021, will consist of a critical design review in preparation for construction. If successful, construction will begin at Lockheed Martin’s Skunk Work‘s facility in Palmdale, followed by a series of test flights and culminating with the delivery of the craft to NASA.

Phase Two, scheduled to begin in 2022, will consist of NASA flying the X-plane in the supersonic test range over Edwards Air Force Base in southern California to see if it is safe for operations in the National Airspace System. Phase Three, running from 2023 to 2025, will consist of the first community response test flights (staged from Armstrong Air Force Base) followed by further test flights over four to six U.S. cities.

The data gathered from these community response tests will then be delivered to the FAA and the International Civil Aviation Organization (ICAO) – currently targeted for delivery in 2025 – so they can adopt new rules based on perceived sound levels. If the Low-Boom Flight Demonstrator should prove to be effective, commercial supersonic flights over land may finally become feasible.

And be sure to enjoy this video of the X-plane’s development, courtesy of NASA:

Further Reading: NASA

April 6, 2018April 9, 2018 by Matt Williams

Could There Be Life in the Cloudtops of Venus?

According to a new study, microbial life could exist in Venus' cloud tops, where temperature and pressure conditions are favorable. Credit: NASA

In the search for life beyond Earth, scientists have turned up some very interesting possibilities and clues. On Mars, there are currently eight functioning robotic missions on the surface of or in orbit investigating the possibility of past (and possibly present) microbial life. Multiple missions are also being planned to explore moons like Titan, Europa, and Enceladus for signs of methanogenic or extreme life.

But what about Earth’s closest neighboring planet, Venus? While conditions on its surface are far too hostile for life as we know it there are those who think it could exist in its atmosphere. In a new study, a team of international researchers addressed the possibility that microbial life could be found in Venus’ cloud tops. This study could answer an enduring mystery about Venus’ atmosphere and lead to future missions to Earth’s “Sister Planet”.

The study, titled “Venus’ Spectral Signatures and the Potential for Life in the Clouds“, recently appeared in the journal Astrobiology. The study was led by Sanjay Limaye of the University of Wisconsin-Madison’s Space Science and Engineering Center and included members from NASA’s Ames Research Center, NASA’s Jet Propulsion Laboratory, California State Polytechnic University, the Birbal Sahni Institute of Palaeosciences, and the University of Zielona Góra.

*Artist’s impression of the surface of Venus, showing its lightning storms and a volcano in the distance. Credit and ©: European Space Agency/J. Whatmore*

For the sake of their study, the team considered the presence of UV contrasts in Venus’ upper atmosphere. These dark patches have been a mystery since they were first observered nearly a century ago by ground-based telescopes. Since then, scientists have learned that they are made up of concentrated sulfuric acid and other unknown light-absorbing particles, which the team argues could be microbial life.

As Limaye indicated in a recent University of Wisconsin-Madison press statement:

“Venus shows some episodic dark, sulfuric rich patches, with contrasts up to 30 – 40 percent in the ultraviolet, and muted in longer wavelengths. These patches persist for days, changing their shape and contrasts continuously and appear to be scale dependent.”

To illustrate the possibility that these streaks are the result of microbial life, the team considered whether or not extreme bacteria could survive in Venus’ cloud tops. For instance, the lower cloud tops of Venus (47.5 to 50.5 km above the surface) are known to have moderate temperature conditions (~60 °C; 140 °F) and pressure conditions that are similar to that of Earth at sea level (101.325 kPa).

This is far more hospitable than conditions on the surface, where temperatures reach 737 K (462 C; 860 F) and atmospheric pressure is 9200 kPa (92 times that of Earth at sea level). In addition, they considered how on Earth, bacteria has been found at altitudes as high as 41 km (25 mi). On top of that, there are many cases where extreme bacteria here on Earth that could survive in an acidic environment.

A composite image of the planet Venus as seen by the Japanese probe Akatsuki. The clouds of Venus could have environmental conditions conducive to microbial life. Credit: JAXA/Institute of Space and Astronautical Science

As Rakesh Mogul, a professor of biological chemistry at California State Polytechnic University and a co-author on the study, indicated, “On Earth, we know that life can thrive in very acidic conditions, can feed on carbon dioxide, and produce sulfuric acid.” This is consistent with the presence of micron-sized sulfuric acid aerosols in Venus upper atmosphere, which could be a metabolic by-product.

In addition, the team also noted that according to some models, Venus had a habitable climate with liquid water on its surface for as long as two billion years – which is much longer than what is believed to have occurred on Mars. In short, they speculate that life could have evolved on the surface of Venus and been swept up into the atmosphere, where it survived as the planet experienced its runaway greenhouse effect.

This study expands on a proposal originally made by Harold Morowitz and famed astronomer Carl Sagan in 1967 and which was investigated by a series of probes sent to Venus between 1962 and 1978. While these missions indicated that surface conditions on Venus ruled out the possibility of life, they also noted that conditions in the lower and middle portions of Venus’ atmosphere – 40 to 60 km (25 – 27 mi) altitude – did not preclude the possibility of microbial life.

For years, Limaye has been revisiting the idea of exploring Venus’ atmosphere for signs of life. The inspiration came in part from a chance meeting at a teachers workshop with Grzegorz Slowik – from the University of Zielona Góra in Poland and a co-author on the study – who told him of how bacteria on Earth have light-absorbing properties similar to the particles that make up the dark patches observed in Venus’ clouds.

*Aircraft like the Venus Atmospheric Maneuverable Platform (VAMP) could explore the cloud tops of Venus for possible signs of life. Credit: Northrop Grumman Corp*

While no probe that has sampled Venus’ atmosphere has been capable of distinguishing between organic and inorganic particles, the ones that make up Venus’ dark patches do have comparable dimensions to some bacteria on Earth. According to Limaye and Mogul, these patches could therefore be similar to algae blooms on Earth, consisting of bacteria that metabolizes the carbon dioxide in Venus’ atmosphere and produces sulfuric acid aerosols.

In the coming years, Venus’ atmosphere could be explored for signs of microbial life by a lighter than air aircraft. One possibility is the Venus Aerial Mobil Platform (VAMP), a concept currently being researched by Northrop Grumman (shown above). Much like lighter-than-air concepts being developed to explore Titan, this vehicle would float and fly around in Venus’ atmosphere and search the cloud tops for biosignatures.

Another possibility is NASA’s possible participation in the Russian Venera-D mission, which is currently scheduled to explore Venus during the late 2020s. This mission would consist of a Russian orbiter and lander to explore Venus’ atmosphere and surface while NASA would contribute a surface station and maneuverable aerial platform.

Another mystery that such a mission could explore, which has a direct bearing on whether or not life may still exist on Venus, is when Venus’ liquid water evaporated. In the last billion years or so, the extensive lava flows that cover the surface have either destroyed or covered up evidence of the planet’s early history. By sampling Venus’ clouds, scientists could determine when all of the planet’s liquid water disappeared, triggering the runaway greenhouse effect that turned it into a hellish landscape.

NASA is currently investigating other concepts to explore Venus’ hostile surface and atmosphere, including an analog robot and a lander that would use a Sterling engine to turn Venus’ atmosphere into a source of power. And with enough time and resources, we might even begin contemplating building floating cities in Venus atmosphere, complete with research facilities.

Further Reading: Space Science and Engineering Center, Astrobiology

April 5, 2018April 5, 2018 by Matt Williams

The Most Distant Star Ever Seen, Only 4.4 Billion Years After the Big Bang

Composite image showing the discovery of the most distant known star using the NASA/ESA Hubble Space Telescope. Credit: NASA & ESA and P. Kelly (University of California, Berkeley)

In 1990, the Hubble Space Telescope was placed into Low Earth Orbit. Since then, Hubble has gone on to become the most well-known space observatory and has revealed some never-before-seen things about our Universe. Despite the subsequent deployment of several flagship telescopes – like the Kepler Space Telescope, the Chandra X-ray Observatory and the Spitzer Space Telescope – Hubble is still accomplishing some amazing feats.

For instance, a team of astronomers recently used Hubble to locate the most distant star ever discovered. This hot blue star, which was located in a galaxy cluster, existed just 4.4 billion years after the Big Bang. The discovery of this star is expected to provide new insights into the formation and evolution of stars and galaxy clusters during the early Universe, as well as the nature of dark matter itself.

The discovery was made by an international team of scientists led by Patrick Kelly (of the University of Minnesota), Jose Diego (of the Instituto de Física de Cantabria in Spain) and Steven Rodney (of the University of South Carolina). Together, they observed the distant star in the galaxy cluster MACS J1149-2223 in April 2016 while studying the supernova explosion known as heic1525 (aka. Refsdal).

Using a technique known as gravitational microlensing, team relied on the total mass of the galaxy cluster itself to magnify the light coming from the supernova. However, while looking for this supernova, the team found an unexpected point source of light in the same galaxy. As Patrick Kelly explained in a recent Hubble press release:

“Like the Refsdal supernova explosion the light of this distant star got magnified, making it visible for Hubble. This star is at least 100 times farther away than the next individual star we can study, except for supernova explosions.”

The light observed from this star – named Lensed Star 1 (LS1) – was emitted just 4.4 billion years after the Big Bang (when the Universe was just 30% of its current age). The light was only detectable thanks to the microlensing effect caused by mass of the galaxy cluster and a compact object about three times the mass of our Sun within the galaxy itself. This allowed for the light coming from the star to be magnified by a factor of 2000.

Interestingly enough, the team also realized that this was not the first time this star had been observed. During a previous observation of the galaxy cluster, made in October 2016, the star was also acquired in an image – but went unnoticed at the time. As Diego noted:

“We were actually surprised to not have seen this second image in earlier observations, as also the galaxy the star is located in can be seen twice. We assume that the light from the second image has been deflected by another moving massive object for a long time — basically hiding the image from us. And only when the massive object moved out of the line of sight the second image of the star became visible.”

After finding the star in their survey, the team used Hubble again to obtain spectra from LS1 and determined that it is a B-type supergiant star – an extremely bright and blue class of star that has several times the mass of our Sun and is more than twice as hot. Given the star’s age, the discovery of LS1 is find on its own. At the same time, the discovery of this star will allow astronomers to gain new insights into the galaxy cluster itself.

As Steven Rodney indicated, “We know that the microlensing was caused by either a star, a neutron star, or a stellar-mass black hole.” As such, the discovery of LS1 will allow astronomers to study these objects (the latter of which are invisible) and estimate how many of them exist within this galaxy cluster.

Learning more about the constituents of galaxy clusters – the largest and most massive structures in the Universe – will also provide important clues about the composition of the Universe overall and how it evolved over time. This includes the important role played by dark matter in the evolution the Universe. As Kelly explained:

“If dark matter is at least partially made up of comparatively low-mass black holes, as it was recently proposed, we should be able to see this in the light curve of LS1. Our observations do not favour the possibility that a high fraction of dark matter is made of these primordial black holes with about 30 times the mass of the Sun.”

With the deployment of next-generation telescopes – like the James Webb Space Telescope – astronomers hope to learn even more about the earliest stars in the Universe. In so doing, they will be able to learn more about how it evolved over the past 10 billion years or so, and gain vital clues as to how dark matter played a role. In the meantime, Hubble still plays an all-important role in expanding our understanding of the cosmos.

And be sure to enjoy this episode of Hubblecast that explains this impressive find, courtesy of the ESA:

Further Reading: Hubble Space Telescope