In a series of papers, Professor Loeb and Michael Hippke indicate that conventional rockets would have a hard time escaping from certain kinds of extra-solar planets. Credit: NASA/Tim Pyle
Decades after Enrico Fermi’s uttered his famous words – “Where is everybody?” – the Paradox that bears his name still haunts us. Despite repeated attempts to locate radio signals coming from space and our ongoing efforts to find visible indications of alien civilizations in distant star systems, the search extra-terrestrial intelligence (SETI) has yet to produce anything substantive.
View from the surface of Pluto, showing its large moon Charon in the distance. Credit: New York Times
On July 14th, 2015, the New Horizons mission made history when it became the first spacecraft to conduct a flyby of Pluto and its moons. In the course of making its way through this system, the probe gathered volumes of data on Pluto and its many satellites using a sophisticated suite of instruments. These included the first detailed images of what Pluto and its largest moon (Charon) look like up close.
And while scientists are still analyzing the volumes of data that the probe has sent home (and probably will be for years to come), the New Horizons mission team has given us plenty of discoveries to mull over in the meantime. For instance, using the many images taken by the mission, they recently created a series of high-quality, highly-detailed global maps of Pluto and Charon.
The maps were created thanks to the plethora of images that were taken by New Horizons’ Long-Range Reconnaissance Imager (LORRI) and its Multispectral Visible Imaging Camera (MVIC). Whereas LORRI is a telescopic camera that was responsible for obtaining encounter and high-resolution geologic data of Pluto at long distances, the MVIC is an optical and infrared instrument that is part of the Ralph instrument – the main imaging device of the probe.
Global mosaic of Pluto, based on images obtained by the LORRI and MVIC instruments onboard New Horizons. Credits: NASA/JHUAPL/SwRI/LPI
The Principal Investigator (PI) for the LORRI instrument is Andy Cheng, and it is operated from Johns Hopkins University Applied Physics Laboratory (JHUAPL) in Laurel, Maryland. Alan Stern is the PI for the MVIC and Ralph instruments, which are operated from the Southwest Research Institute (SwRI) in San Antonio, Texas. And as you can plainly see, the maps are quite detailed and eye-popping!
Dr. Stern, who is also the PI of the New Horizons mission, commented on the release of the maps in a recent NASA press statement. As he stated, they are just the latest example of what the New Horizons mission accomplished during its historic mission:
“The complexity of the Pluto system — from its geology to its satellite system to its atmosphere— has been beyond our wildest imagination. Everywhere we turn are new mysteries. These new maps from the landmark exploration of Pluto by NASA’s New Horizons mission in 2015 will help unravel these mysteries and are for everyone to enjoy.”
Global mosaic of Charon, based on images obtained by the LORRI and MVIC instruments onboard New Horizons. Credits: NASA/JHUAPL/SwRI/LPI
And these were not the only treats to come from the New Horizons team in recent days. In addition, the mission scientists used actual New Horizons data and digital elevation models to create flyover movies that show what it would be like to pass over Pluto and Charon. These videos offer a new perspective on the system and showcase the many unusual features that were discovered on both bodies.
The video of the Pluto flyover (shown above) begins over the highlands that are located to the southwest of Sputnik Planitia – the nitrogen ice basin that measures some 1,050 by 800 km (650 by 500 mi) in size. These plains constitute the western lobe of the feature known as Tombaugh Regio, the heart-shaped region that is named after the man who discovered Pluto in 1930 – Clyde Tombaugh.
The flyover also passes by cratered terrain of Cthulhu Macula before moving north past the highlands of Voyager Terra. It then turns south towards the pitted region known as Pioneer Terra before concluding over Tartarus Dorsa, a mountainous region that also contains bowl-shaped ice and snow features called penitentes (which are found on Earth and are formed by erosion).
The flyover video of Charon begins over the hemisphere that the New Horizons mission saw during its closest approach to the moon. The view then descends over Serenity Chasma, the wide and deep canyon that is named after the ship from the sci-fi series Firefly. This feature is part of the vast equatorial belt of chasms on Charon, which is one of the longest in the Solar System – 1,800 km (1,100 mi) long 7.5 km (4.5 mi) deep.
The view then moves north, passing over the Dorothy Gale crater and the dark polar region known as Mordor Macula (appropriately named after the domain of the Dark Lord Sauron in The Lord of the Rings). The video then turn south to fly over the northern terrain known as Oz Terra before finishing over the equatorial plans of Vulcan Planum and the mountain of Clarke Montes.
These videos were color-enhanced in order to bring out the surface details, and the topographic relief was exaggerated by a factor or two to three to emphasize the topography of Pluto and its largest moon. Digital mapping and rendering of these videos was performed by Paul Schenk and John Blackwell of the Lunar and Planetary Institute (LPI) in Houston.
It may be many years before another mission is able to travel to the Trans-Neptunian region and Kuiper Belt. As a result, the maps and videos and images that were taken by the New Horizons mission may the last glimpse some us get of the Pluto system. Luckily, the New Horizons mission has provided scientists and the general public with enough information to keep them busy and fascinated for years!
Totality! An incredible moment from the March 29th, 2006 total solar eclipse. Credit and copyright: Alan Dyer/Amazing Sky Photography
Have you heard?
I remember, getting into astronomy as a kid back in the 1970s, building a pinhole projector in a shoe box and watching the partial solar eclipse of February 26th, 1979 from our living room in northern Maine. I had no Learjet, no magic carpet to whisk me off to that thin thread of a path of totality way out west along the Pacific coast. As I settled for the 66% partial solar eclipse, I remember news reports stating that a total solar eclipse won’t cross the United States again until… August 21st, 2017.
That date is almost upon us now, only one month from this coming Friday.
An animation of the August 21st eclipse. Credit: NASA/GSFC/AT Sinclair
This total solar eclipse is one for the ages, THE big ticket event for 2017. Umbraphiles (those who chase eclipses) have been planning for this one for decades, and it’s already hard to find a room along the path. Fear not, as you only need to be within striking distance the day of the eclipse to reach totality, though expect the roads to be congested that Monday morn.
The eclipse is indeed the first time totality touches the contiguous (“lower 48”) United States since 1979, and the first total solar eclipse to cross the United States since almost a century ago on June 8th 1918. A total solar eclipse did cross Hawaii on July 11th, 1991.
The path of the August 21st eclipse over the U.S. Credit: Michael Zeiler/Eclipse-Maps.
Partial phases for the eclipse begin at 15:47 Universal Time (UT) and span 5 hours and 18 minutes until 21:04 UT. The partial aspect of the eclipse touches all continents except Antarctica and Australia. The 115 kilometer wide shadow of Earth’s moon (known as the umbra) first makes landfall over the Oregon coast at 17:16 UT /10:16 Pacific Daylight Saving time (PDT) and races eastward at 3,900 kilometers per second. The shadow touches 14 states, just briefly nicking Montana and Iowa. Maximum totality of 2 minutes, 40 seconds occurs near Carbondale, Illinois.
Seen a partial solar eclipse before and wonder what the big deal is? You really need to get to the path of totality for the full eclipse experience. Millions live in the path of the August 21st eclipse, and millions more within an easy day drive. We witnessed the May 10th, 1994 annular eclipse from the shores of Lake Erie in Sandusky, Ohio, and can attest that 1% of the Sun at midday is still pretty darned bright.
A partial eclipse rising over the Vehicle Assembly Building at the Kennedy Space Center. Credit: Dave Dickinson
Action really gets interesting moments before totality sweeps over the landscape. Be sure to keep an eye out for shadow bands flitting across the ground, an effect notoriously hard to photograph. It’s safe to drop those glasses moments before totality, when you’ll see those final rays of sunlight streaming through the valleys along the limb of the Moon, creating what’s known as Baily’s Beads or the Diamond Ring Effect. You’re now in the realm of the shadow of the Moon, an ethereal shadow world turned on its head. I dare you to blink. Looking sunward, you’ll see the pearly corona of the Sun, a white halo about as bright as a Full Moon spied only during totality.
Think about it: you knew this moment was coming, perhaps you’d been planning for it for years… but would you think as an average citizen thousands or millions of years ago if you were suddenly confronted with such as strange sky?
And all too soon, it’s over.
Be sure to keep an eye out for planets and bright stars during the eclipse. Totality is a late morning affair out west, and an early afternoon event for the US East Coast. All naked eye planets except Saturn are above the horizon during totality, covering a span of about 80 degrees from Jupiter to Venus. Look just one degree from the eclipsed Sun and you might just spy the star Regulus occulted by the Moon shortly after the eclipse.
The orientation of the planets and bright stars during totality. Credit: Stellarium.
Perhaps you’re planning on aiming a battery of cameras skyward during the eclipse, or maybe, you’re simply planning on simply enjoying the moment, then photographing the next one. The Eclipse MegaMovie project is planning on capturing the scene down the eclipse path. NASA will also be flying overhead with converted WB-57F aircraft, looking to capture high definition video in the visible and infrared wavelengths during the eclipse.
Preparing for the eclipse. Credit: Dave Dickinson
You need to take the same safety precautions observing the partial phases of the eclipse as you would during ordinary solar observing. Use only a filtered telescope designed to look at the Sun, or solar eclipse glasses with an ISO 12312-2 rating. Make sure that filter fits snugly over the aperture of the telescope and cannot be removed by curious prying hands or high winds, and that all finder-scopes are removed, stowed and/or covered. Also, don’t try and use one of those old screw-on eyepiece solar filters that came with old department store 60mm refractors, as they can heat up and crack. Likewise, be careful when projecting the Sun through a telescope onto a piece of paper, as it can heat up and damage the optics.
If you don’t think the danger is real, read this amazing recent interview with an optometrist on Space.com, where he states you can actually see the crescent Sun burned into the backs of patient’s eyes who stared too long at a partial solar eclipse (!) It’s a permanent souvenir you don’t want to have. Don’t be like 18th century psychologist Gustav Fechner who blinded himself staring at the Sun, mesmerized by the glare of lingering afterimages.
Seen on the streets of Paducah, Kentucky… a harbinger of things to come? Credit: Dave Dickinson
And though we can predict eclipses centuries out, there’s one thing we won’t know eclipse day: what the weather plans on doing. Best bets are for clear skies out west, though you only need a gap in the clouds to see the Sun. We’ll be running a final post on Universe Today just days prior to the eclipse looking at weather prospects, solar activity and prospects for transits of the International Space Station and possible views from space.
The umbra of the Moon on Earth as seen from Mir in 1999. Credit: NASA/Roscosmos.
The second eclipse season for 2017 begins with a partial lunar eclipse favoring on August 7th… we’ve got you covered on that as well. And us? We’ll be watching the event from the Pisgah Astronomical Research Institute (PARI) in Smoky Mountains just outside of Asheville, North Carolina for a glorious 107 seconds of totality.
And after that? Well, totality visits that same living room in northern Maine on April 8th, 2024… I think I know where I’ll be then.
The path of the 2017 and 2024 eclipses. Credit: Michael Zeiler/Eclipse Maps.
A request- observing the eclipse from the path of totality? I’m planning on doing a state-by-state roundup post eclipse, perhaps with a paragraph of personal impressions from each observer. Let us know what your plans are!
-Read more about the August 21st total solar eclipse, plus the true tale of Edison’s Chickens and the 1878 total solar eclipse in out free e-guide to 101 Astronomical Events for 2017.
Accroding to new research, the Milky Way may still bear the marks of "ancient impacts". Credit: NASA/Serge Brunier
Understanding how the Universe came to be is one of the greater challenges of being an astrophysicist. Given the observable Universe’s sheer size (46.6 billion light years) and staggering age (13.8 billion years), this is no easy task. Nevertheless, ongoing observations, calculations and computer simulations have allowed astrophysicists to learn a great deal about how galaxies and larger structures have changed over time.
For example, a recent study by a team from the University of Kentucky (UK) has challenged previously-held notions about how our galaxy has evolved to become what we see today. Based on observations made of the Milky Way’s stellar disk, which was previously thought to be smooth, the team found evidence of asymmetric ripples. This indicates that in the past, our galaxy may have been shaped by ancient impacts.
This study evolved from Ferguson’s senior thesis, which was overseen by Prof. Gardner. At the time, Ferguson sought to expand on previous research by Gardner and Yanny, which also sought to understand the presence of ripples in our galaxy’s stellar disk. For the sake of this new study, the team relied on data obtained by the Sloan Digital Sky Survey‘s (SDSS) 2.5m Telescope, located at the Apache Point Observatory in New Mexico.
This allowed the team to examine the spatial distribution of 3.6 million stars in the Milky Way Galaxy, from which they confirmed the presence of asymmetric ripples. These, they claim, can be interpreted as evidence of the Milky Way’s ancient impacts – in other words, that these ripples resulted from our galaxy coming into contact with other galaxies in the past.
These could include a merger between the Milky Way and the Sagittarius dwarf galaxy roughly 0.85 billion years ago, as well as our galaxy’s current merger with the Canis Major dwarf galaxy. As Prof. Gardner explained in a recent UK press release:
“These impacts are thought to have been the ‘architects’ of the Milky Way’s central bar and spiral arms. Just as the ripples on the surface of a smooth lake suggest the passing of a distant speed boat, we search for departures from the symmetries we would expect in the distributions of the stars to find evidence of ancient impacts. We have found extensive evidence for the breaking of all these symmetries and thus build the case for the role of ancient impacts in forming the structure of our Milky Way.”
Illustration showing a stage in the predicted merger between our Milky Way galaxy and the neighboring Andromeda galaxy, as it will unfold over the next several billion years. Credit: NASA; ESA; Z. Levay and R. van der Marel, STScI; T. Hallas; and A. Mellinger
As noted, Gardner’s previous work also indicated that when it came to north/south symmetry of stars in the Milky Way’s disk, there was a vertical “ripple”. In other words, the number of stars that lay above or below the stellar disk would increase from one sampling to the next the farther they looked from the center of the galactic disk. But thanks to the most recent data obtained by the SDSS, the team had a much larger sample to base their conclusions on.
And ultimately, these findings confirmed the observations made by Ferguson and Lally, and also turned up evidence of an asymmetry in the plane of the galactic disk as well. As Ferguson explained:
“Having access to millions of stars from the SDSS allowed us to study galactic structure in an entirely new way by breaking the sky up into smaller regions without loss of statistics. It has been incredible watching this project evolve and the results emerge as we plotted the stellar densities and saw intriguing patterns across the footprint. As more studies are being done in this field, I am excited to see what we can learn about the structure of our galaxy and the forces that helped to shape it.”
Understanding how our galaxy evolved and what role ancient impact played is essential to understanding the history and evolution of the Universe as a whole. And in addition to helping us confirm (or update) our current cosmological models, studies like this one can also tell us much about what lies in store for our galaxy billions of years from now.
For decades, astronomers have been of the opinion that in roughly 4 billion years, the Milky Way will collide with Andromeda. This event is likely to have tremendous repercussions, leading to the merger of both galaxy’s supermassive black holes, stellar collisions, and stars being ejected. While it’s doubtful humanity will be around for this event, it would still be worthwhile to know how this process will shape our galaxy and the local Universe.
Artist's impression of rocky exoplanets orbiting Gliese 832, a red dwarf star just 16 light-years from Earth. Credit: ESO/M. Kornmesser/N. Risinger (skysurvey.org).
Astronomers have been listening to radio waves from space for decades. In addition to being a proven means of studying stars, galaxies, quasars and other celestial objects, radio astronomy is one of the main ways in which scientists have searched for signs of extra-terrestrial intelligence (ETI). And while nothing definitive has been found to date, there have been a number of incidents that have raised hopes of finding an “alien signal”.
In the most recent case, scientists from the Arecido Observatory recently announced the detection of a strange radio signal coming from Ross 128 – a red dwarf star system located just 11 light-years from Earth. As always, this has fueled speculation that the signal could be evidence of an extra-terrestrial civilization, while the scientific community has urged the public not to get their hopes up.
The discovery was part of a campaign being conducted by Abel Méndez – the director of the Planetary Habitability Laboratory (PHL) in Peurto Rico – and Jorge Zuluaga of the Faculty of Exact and Natural Sciences at the University of Antioquia, Colombia. Inspired by the recent discoveries around Proxima Centauri and TRAPPIST-1, the GJ 436 campaign relied on data from Arecibo Observatory to look for signs of exoplanets around nearby red dwarf stars.
Arecibo Observatory, the world’s biggest single dish radio telescope, was and is still being used to image comet 45P/H-M-P. Courtesy of the NAIC – Arecibo Observatory, a facility of the NSF
In the course of looking at data from stars systems like Gliese 436, Ross 128, Wolf 359, HD 95735, BD +202465, V* RY Sex, and K2-18 – which was gathered between April and May of 2017 – they noticed something rather interesting. Basically, the data indicated that an unexplained radio signal was coming from Ross 128. As Dr. Abel Mendez described in a blog post on the PHL website:
“Two weeks after these observations, we realized that there were some very peculiar signals in the 10-minute dynamic spectrum that we obtained from Ross 128 (GJ 447), observed May 12 at 8:53 PM AST (2017/05/13 00:53:55 UTC). The signals consisted of broadband quasi-periodic non-polarized pulses with very strong dispersion-like features. We believe that the signals are not local radio frequency interferences (RFI) since they are unique to Ross 128 and observations of other stars immediately before and after did not show anything similar.”
They also conducted observations of Barnard’s star on that same day to see if they could note similar behavior coming from this star system. This was done in collaboration with the Red Dots project, a European Southern Observatory (ESO) campaign that is also committed to finding exoplanets around red dwarf stars. This program is the successor to the ESO’s Pale Red Dot campaign, which was responsible for discovering Proxima b last summer.
Images of the star systems examined by the GJ 436 Campaign. Credit: PHL/Abel Méndez
As of Monday night (July 17th), Méndez updated his PHL blog post to announced that with the help of SETI Berkeley with the Green Bank Telescope, that they had successfully observed Ross 128 for the second time. The data from these observatories is currently being collected and processed, and the results are expected to be announced by the end of the week.
In the meantime, scientists have come up with several possible explanations for what might be causing the signal. As Méndez indicated, there are three major possibilities that he and his colleagues are considering:
“[T]hey could be (1) emissions from Ross 128 similar to Type II solar flares, (2) emissions from another object in the field of view of Ross 128, or just (3) burst from a high orbit satellite since low orbit satellites are quick to move out of the field of view. The signals are probably too dim for other radio telescopes in the world and FAST is currently under calibration.”
Unfortunately, each of these possibilities have their own drawbacks. In the case of a Type II solar flare, these are known to occur at much lower frequencies, and the dispersion of this signal appears to be inconsistent with this kind of activity. In the case of it possibly coming from another object, no objects (planets or satellites) have been detected within Ross 128’s field of view to date, thus making this unlikely as well.
The stars currently being examined as part of the GJ 436 campaign. Credit: PHL/Abel Méndez
Hence, the team has something of a mystery on their hands, and hopes that further observations will allow them to place further constrains on what the cause of the signal could be. “[W]e might clarify soon the nature of its radio emissions, but there are no guarantees,” wrote Méndez. “Results from our observations will be presented later that week. I have a Piña Colada ready to celebrate if the signals result to be astronomical in nature.”
And just to be fair, Méndez also addressed the possibility that the signal could be artificial in nature – i.e. evidence of an alien civilization. “In case you are wondering,” he wrote, “the recurrent aliens hypothesis is at the bottom of many other better explanations.” Sorry, alien-hunters. Like the rest of us, you’ll just have to wait and see what can be made of this signal.
Enlarged region of the Saraswati Supercluster, the largest known structure in the Universe, showing the distribution of galaxies. Credit: IUCAA
The Milky Way Galaxy, which measures 100,000 to 180,000 light years (31 – 55 kiloparsecs) in diameter and contains 100 to 400 billion stars, is so immense that it boggles the mind. And yet, when it comes to the large-scale structure of the Universe, our galaxy is merely a drop in the bucket. Looking farther, astronomers have noted that galaxies form clusters, which in turn form superclusters – the largest known structures in the Universe.
The supercluster in which our galaxy resides is known as the Laniakea Supercluster, which spans 500 million light-years. But thanks to a new study by a team of Indian astronomers, a new supercluster has just been identified that puts all previously known ones to shame. Known as Saraswati, this supercluster is over 650 million light years (200 megaparsecs) in diameter, making it one the largest large-scale structures in the known Universe.
The distribution of galaxies, from Sloan Digital Sky Survey (SDSS), in Saraswati supercluster. Credit: IUCAA
For the sake of their study, the team relied on data obtained by the Sloan Digital Sky Survey (SDSS) to examine the large-scale structure of the Universe. In the past, astronomers have found that the cosmos is hierarchically assembled, with galaxies being arranged in clusters, superclusters, sheets, walls and filaments. These are separated by immense cosmic voids, which together create the vast “Cosmic Web” structure of the Universe.
Superclusters, which are the largest coherent structures in the Cosmic Web, are basically chains of galaxies and galaxy clusters that can extend for hundreds of millions of light years and contain trillions of stars. In the end, the team found a supercluster located about 4 billion (1226 megaparsecs) light-years from Earth – in the constellation Pisces – that is 600 million light-years wide and may contain the mass equivalent of over 20 million billion suns.
They gave this supercluster the name “Saraswati”, the name of an ancient river that played an important role in the emergence of Indian civilization. Saraswait is also the name of a goddess that is worshipped in India today as the keeper of celestial rivers and the goddess of knowledge, music, art, wisdom and nature. This find was particularly surprising, seeing as how Saraswati was older than expected.
Essentially, the supercluster appeared in the SDSS data as it would have when the Universe was roughly 10 billion years old. So not only is Saraswati one of the largest superclusters discovered to date, but its existence raises some serious questions about our current cosmological models. Basically, the predominant model for cosmic evolution does not predict that such a superstructure could exist when the Universe was 10 billion years old.
Diagram of the Lambda-CDM model, which shows cosmic evolution from the Big Bang/Inflation Era and the subsequent expansion of the universe. Credit: Alex Mittelmann.
Known as the “Cold Dark Matter” model, this theory predicts that small structures (i.e. galaxies) formed first in the Universe and then congregated into larger structures. While variations within this model exist, none predict that something as large as Saraswati could have existed 4 billion years ago. Because of this, the discovery may require astronomers to rethink their theories of how the Universe became what it is today.
To put it simply, the Saraswati supercluster formed at a time when Dark Energy began to dominate structure formation, replacing gravitation as the main force shaping cosmic evolution. As Joydeep Bagchi, a researcher from IUCAA and the lead author of the paper, and co-author Shishir Sankhyayan (of IISER) explained in a IUCAA press release:
‘’We were very surprised to spot this giant wall-like supercluster of galaxies… This supercluster is clearly embedded in a large network of cosmic filaments traced by clusters and large voids. Previously only a few comparatively large superclusters have been reported, for example the ‘Shapley Concentration’ or the ‘Sloan Great Wall’ in the nearby universe, while the ‘Saraswati’ supercluster is far more distant one. Our work will help to shed light on the perplexing question; how such extreme large scale, prominent matter-density enhancements had formed billions of years in the past when the mysterious Dark Energy had just started to dominate structure formation.’’
As such, the discovery of this most-massive of superclusters may shed light on how and when Dark Energy played an important role in supercluster formation. It also opens the door to other cosmological theories that are in competition with the CDM model, which may offer more consistent explanations as to why Saraswati could exist 10 billion years after the Big Bang.
One thing is clear thought: this discovery represents an exciting opportunity for new research into cosmic formation and evolution. And with the aid of new instruments and observational facilities, astronomers will be able to look at Saraswait and other superclusters more closely in the coming years and study just how they effect their cosmic environment.
A new research study from Oxford indicates that the tardigrade, an eight-legged micro-animal, will survive until the sun dies - long after humans are gone. Credit: Oxford
Like all living creatures, stars have a natural lifespan. After going through their main sequence phase, they eventually exhaust their nuclear fuel and begin the slow process towards death. In our Sun’s case, this will consist of it growing in size and entering the Red Giant phase of its evolution. When that happens, roughly 5.4 billion years from now, the Sun will encompass the orbit’s of Mercury, Venus, and maybe even Earth.
However, even before this happens, astronomers theorize that the Sun will dramatically heat up, which will render Earth uninhabitable to most species. But according to a new study by a team of researchers from Oxford and the University of Harvard, the species known as tardigrades (aka. the “water bear”) will likely survive even after humanity and all other species have perished.
This study, which was recently published in the journal Scientific Reports under the title “The Resilience of Life to Astrophysical Events“, was conducted by Dr. David Sloan, Dr. Rafael Alves Batista – from the Department of Astrophysics at Oxford University – and Dr. Abraham Loeb of the Harvard-Smithsonian Center for Astrophysics (CfA). As they indicate, previous studies into the effect Solar evolution will have on life have been rather lopsided.
Artist’s impression of the Earth scorched by our Sun as it enters its Red Giant Branch phase. Credit: Wikimedia Commons/Fsgregs
Essentially, much attention has been dedicated to whether or not humanity will survive our Sun leaving its main sequence phase. Comparatively, very little research has been conducted on whether or not life itself (and which lifeforms) will be able to survive this change. As such, they considered the most statistically-likely events that would be capable of completely sterilizing an Earth-like planet, and sought to determine what lifeforms could endure them.
As Dr. Loeb told Universe Today via email, their team wanted to consider if there was an extinction-level event that could eliminate all life on Earth (not just humans):
“We wanted to find out how long life may survive on a planet once formed. Most previous studies focused on the survival of humans which are very sensitive to changes in the atmosphere or climate of the Earth and can be eliminated by the impact of an asteroid (nuclear winter) or bad politics.”
What they found was that the species Milnesium tardigradum would survive all potential astrophysical catastrophes. What’s more, they estimated that these creatures will be around for another 10 billion years at least – far longer than what is anticipated for the human race! As Loeb indicates, this was not an outcome that they were expecting.
“To our surprise, tardigrades are likely to survive all astrophysical catastrophes,” he said. “Most likely, the DNA of tardigrades is able to repair itself quickly due to damage encountered by the environment. The process is not fully understood, and there is a group at Harvard University who studies the SNA of tardigrades with the hope of understanding it better.”
Scanning Electron Microscope (SEM) image of Milnesium tardigradum in active state. Credit: Schokraie E/Warnken U/Hotz-Wagenblatt A/Grohme MA/Hengherr S, et al.
To be fair, it has been known for some time that Tardigrades are the most resilient life form on Earth. Not only can they survive for up to 30 years without food or water (half their natural lifespan), they can also survive temperatures of up to 150 °C (302 °F) and as low as -200 °C (-328 °F). They have also shown themselves to be capable of enduring extremes in pressure, ranging from the 6000 atmospheres to the vacuum of open space.
Under these conditions, the research team concluded that they are likely to survive the Sun becoming a red giant and irradiating Earth, and will likely be alive even after the Sun has winked out of existence. On top of that, tardigrades can even be brought back to life, under the right circumstances. Much like all life on Earth, tradigrades need water to survive, even though they can survive in a dry state for extended periods of time – up to ten years, in fact.
But even after being deprived of water to the point of death, scientists have found that these organisms can be reanimated once water is reintroduced. This was demonstrated in 2007 when a batch of tardigrades was dehydrated before being launched to Low Earth Orbit (LEO). After being exposed to the hard vacuum of space and UV radiation for 10 days, they were returned to Earth and rehydrated – at which point, the majority were revived and able to produce viable embryos.
The team also concluded that other cataclysmic events – such as an asteroid strike, exploding stars (i.e. a supernovae) or gamma ray bursts – pose no existential threat to tardigrades. As Loeb explained:
“We have found that asteroid impacts are capable of boiling off all the oceans on Earth, but only if the asteroid is more massive than 1018 kg [10,000 trillion metric tons]. Such events are extremely rare and will not happen before the Sun will die; the probability of them happening earlier is less than one part in a million.”
Artist’s concept of a collision between proto-Earth and Theia, believed to happened 4.5 billion years ago. Credit: NASA
In fact, the last time an object large enough to boil the oceans (2 x 1018 kg) collided with Earth occurred roughly 4.51 billion years ago. On this occasion, Earth was struck by a Mars-sized object named Theia, which is believed to be what caused the formation of the Moon. Today, there are only a dozen known asteroids or dwarf planets in the Solar System that have this kind of mass, and none of them will intersect the Earth’s orbit in the future.
As for supernova, they indicated that an exploding star would need to be 0.14 light-years from Earth in order for it to boil the oceans from its surface. Since the closest star to our Sun (Proxima Centauri) is 4.25 light years away, this scenario is not a foreseeable risk. As for gamma-ray bursts, which are even rarer than supernova, the team determined that they too are too far away from Earth to pose a threat.
The implications of this study are quite fascinating. For one, it reminds us just how fragile human life is compared to basic, microscopic life forms. It also demonstrates that similarly hardy organisms could exist in a variety of locations that we may have once considered too hostile for life. As Dr Rafael Alves Batista, one of the co-authors on the study, said in a University of Oxford press release:
“Without our technology protecting us, humans are a very sensitive species. Subtle changes in our environment impact us dramatically. There are many more resilient species’ on earth. Life on this planet can continue long after humans are gone. Tardigrades are as close to indestructible as it gets on Earth, but it is possible that there are other resilient species examples elsewhere in the Universe. In this context there is a real case for looking for life on Mars and in other areas of the Solar System in general. If Tardigrades are earth’s most resilient species, who knows what else is out there?’”
And as Dr. Loeb explained, studies like this have potential benefits that go far beyond assessing our own survivability. Not only do they help us understand life’s ability to endure catastrophic events – which is essential to understanding how and where life could emerge in the Universe – but they also offer possibilities on how we might better our own chances of survival.
“We get a better understanding of the conditions under which life will persist,” he said. “In about a billion years, when the Sun will heat up life will cease, but until then it will continue in some form. Understanding the self-repair mechanism of the DNA on tardigrades could potentially help in combating disease for humans as well.”
And all his time, we thought cockroaches were the toughest critters on the planet, what with their ability to withstand a nuclear holocaust. But these eight-legged creatures, which are arguably cuter than cockroaches too, clearly have the market on toughness cornered. We’re just lucky they only get up to 0.5 mm (0.02 in) in size, otherwise we might have something to worry about!
Inside the Astrotech payload processing facility in Titusville, FL,NASA's massive, insect like Tracking and Data Relay Satellite, or TDRS-M, spacecraft is undergoing preflight processing during media visit on 13 July 2017. TDRS-M will transmit critical science data gathered by the ISS, Hubble and numerous NASA Earth science missions. It is being prepared for encapsulation inside its payload fairing prior to being transported to Launch Complex 41 at Cape Canaveral Air Force Station for launch on a United Launch Alliance (ULA) Atlas V rocket on 3 August 2017. Credit: Ken Kremer/kenkremer.com
Inside the Astrotech payload processing facility in Titusville, FL,NASA’s massive, insect like Tracking and Data Relay Satellite, or TDRS-M, spacecraft is undergoing preflight processing during media visit on 13 July 2017. TDRS-M will transmit critical science data gathered by the ISS, Hubble and numerous NASA Earth science missions. It is being prepared for encapsulation inside its payload fairing prior to being transported to Launch Complex 41 at Cape Canaveral Air Force Station for launch on a United Launch Alliance (ULA) Atlas V rocket on 3 August 2017. Credit: Ken Kremer/kenkremer.com
ASTROTECH SPACE OPERATIONS/KENNEDY SPACE CENTER, FL – The last of NASA’s next generation Tracking and Data Relay Satellites (TRDS) designed to relay critical science data and research observations gathered by the International Space Station (ISS), Hubble and dozens of Earth-orbiting Earth science missions is undergoing final prelaunch clean room preparations on the Florida Space Coast while targeting an early August launch – even as the agency reviews the scheduling impact of a weekend “closeout incident” that “damaged” a key component.
Liftoff of NASA’s $408 million eerily insectoid-looking TDRS-M science relay comsat atop a United Launch Alliance (ULA) Atlas V rocket currently scheduled for August 3 may be in doubt following a July 14 work related incident causing damage to the satellite’s Omni S-band antenna while inside the Astrotech Space Operations facility in Titusville, Florida.
“The satellite’s Omni S-band antenna was damaged during final spacecraft closeout activities,” NASA said in an updated status statement provided to Universe Today earlier today, July 16. NASA did not provide any further details when asked.
Everything had been perfectly on track as of Thursday, July 13 as Universe Today participated in an up close media tour and briefing about the massive probe inside the clean room processing facility at Astrotech Space Operations in Titusville, Fl.
On July 13, technicians were busily working to complete final spacecraft processing activities before its encapsulation inside the nose cone of the ULA Atlas V rocket she will ride to space, planned for the next day on July 14. The satellite and pair of payload fairings were stacked in separate high bays at Astrotech on July 13.
Alas the unspecified “damage” to the TDRS-M Omni S-band antenna unfortunately took place on July 14.
Up close clean room visit with NASA’s newest science data relay comsat – Tracking and Data Relay Satellite-M (TDRS-M) inside the Astrotech payload processing facility high bay in Titusville, FL. Two gigantic fold out antennae’s, plus space to ground antenna dish visible inside the ‘cicada like cocoon’ with solar arrays below. Omni S-band antenna at top. Launch on ULA Atlas V slated for August 2017 from Cape Canaveral Air Force Station, Fl. Credit: Ken Kremer/kenkremer.com
TDRS-M was built by Boeing and engineers are now analyzing the damage in a team effort with NASA. However it’s not known exactly during which closeout activity or by whom the damage occurred.
ULA CEO Tory Bruno tweeted that his company is not responsible and referred all questions to NASA. This may indicate that the antennae was not damaged during the encapsulation procedures inside the ULA payload fairing halves.
“NASA and Boeing are reviewing an incident that occurred with the Tracking and Data Relay Satellite (TDRS-M) on July 14 at Astrotech Space Operations in Titusville, Florida. The satellite’s Omni S-band antenna was damaged during final spacecraft closeout activities” stated NASA.
Up close look at the NASA TDRS-M satellite Omni S-band antenna damaged during clean room processing on July 14, 2017. Launch on ULA Atlas V is slated for Aug. 2017. Credit: Julian Leek
TDRS-M looks like a giant insect – or a fish depending on your point of view. It was folded into flight configuration for encapsulation in the clean room and the huge pair of single access antennas resembled a cocoon or a cicada. The 15 foot diameter single access antennas are large parabolic-style antennas and are mechanically steerable.
What does TDRS do? Why is it important? How does it operate?
“The existing Space Network of satellites like TDRS provide constant communications from other NASA satellites like the ISS or Earth observing satellites like Aura, Aqua, Landsat that have high bandwidth data that needs to be transmitted to the ground,” TDRS Deputy Project Manager Robert Buchanan explained to Universe Today during an interview in the Astrotech clean room.
“TRDS tracks those satellites using antennas that articulate. Those user satellites send the data to TDRS, like TDRS-M we see here and nine other TDRS satellites on orbit now tracking those satellites.”
“That data acquired is then transmitted to a ground station complex at White Sands, New Mexico. Then the data is sent to wherever those user satellites want the data to be sent is needed, such as a science data ops center or analysis center.”
Once launched and deployed in space they will “take about 30 to 40 days to fully unfurl,” Buchanan told me in the Astrotech clean room.
Astrotech is located just a few miles down the road from NASA’s Kennedy Space Center and the KSC Visitor Complex housing the finest exhibits of numerous spaceships, hardware items and space artifacts.
Preflight clean room processing inside the Astrotech payload processing facility preparing NASA’s Tracking and Data Relay Satellite, or TDRS-M, spacecraft for launch on ULA Atlas V in Aug. 2017. Credit: Julian Leek
At this time, the TDRS-M website countdown clock is still ticking down towards a ULA Atlas V blastoff on August 3 at 9:02 a.m. EDT (1302 GMT) from Space Launch Complex 41 (SLC-41) on Cape Canaveral Air Force Station, for a late breakfast delight.
The Aug. 3 launch window spans 40 minutes from 9:02 to 9:42 a.m. EDT.
Whether or not the launch date will change depends on the results of the review of the spacecraft’s health by NASA and Boeing. Several other satellites are also competing for launch slots in August.
“The mission team is currently assessing flight acceptance and schedule. TDRS-M is planned to launch Aug. 3, 2017, on an United Launch Alliance (ULA) Atlas V rocket from Cape Canaveral Air Force Station in Florida,” NASA explained.
NASA’s Tracking and Data Relay Satellite, or TDRS-M, spacecraft will be encapsulated inside these two protective payload fairing halves inside the Astrotech payload processing facility high bay in Titusville, FL. Launch on ULA Atlas V slated for August 2017 from Cape Canaveral Air Force Station, Fl. Credit: Ken Kremer/kenkremer.com
TDRS-M, spacecraft, which stands for Tracking and Data Relay Satellite – M is NASA’s new and advanced science data relay communications satellite that will transmit research measurements and analysis gathered by the astronaut crews and instruments flying abroad the International Space Station (ISS), Hubble Space Telescope and over 35 NASA Earth science missions including MMS, GPM, Aura, Aqua, Landsat, Jason 2 and 3 and more.
The TDRS constellation orbits 22,300 miles above Earth and provide near-constant communication links between the ground and the orbiting satellites.
Preflight clean room processing inside the Astrotech payload processing facility preparing NASA’s Tracking and Data Relay Satellite, or TDRS-M, spacecraft for launch on ULA Atlas V in Aug. 2017. Credit: Julian Leek
TRDS-M will have S-, Ku- and Ka-band capabilities. Ka has the capability to transmit as much as six-gigabytes of data per minute. That’s the equivalent of downloading almost 14,000 songs per minute says NASA.
The TDRS program is managed by NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
TDRS-M is the third satellite in the third series of NASA’s American’s most powerful and most advanced Tracking and Data Relay Satellites. It is designed to last for a 15 year orbital lifetime.
The first TDRS satellite was deployed from the Space Shuttle Challenger in 1983 as TDRS-A.
TDRS-M was built by prime contractor Boeing in El Segundo, California and is the third of a three satellite series – comprising TDRS -K, L, and M. They are based on the Boeing 601 series satellite bus and will be keep the TDRS satellite system operational through the 2020s.
TDSR-K and TDRS-L were launched in 2013 and 2014.
The Tracking and Data Relay Satellite project is managed at NASA’s Goddard Space Flight Center.
TDRS-M was built as a follow on and replacement satellite necessary to maintain and expand NASA’s Space Network, according to a NASA description.
The gigantic satellite is about as long as two school buses and measures 21 meters in length by 13.1 meters wide.
It has a dry mass of 1800 kg (4000 lbs) and a fueled mass of 3,454 kilogram (7,615 lb) at launch.
Tracking and Data Relay Satellite artwork explains how the TDRS constellation enables continuous, global communications coverage for near-Earth spacecraft. Credit: NASA
TDRS-M will blastoff on a ULA Atlas V in the baseline 401 configuration, with no augmentation of solid rocket boosters on the first stage. The payload fairing is 4 meters (13.1 feet) in diameter and the upper stage is powered by a single-engine Centaur.
TDRS-M will be launched to a Geostationary orbit some 22,300 miles (35,800 km) above Earth.
“The final orbital location for TDRS-M has not yet been determined,” Buchanen told me.
The Atlas V booster is being assembled inside the Vertical Integration Facility (VIF) at SLC-41 and will be rolled out to the launch pad the day before liftoff with the TDRS-M science relay comsat comfortably encapsulated inside the nose cone.
NASA/contractor team poses with the Boeing built and to be ULA launched Tracking and Data Relay Satellite-M inside the inside the Astrotech payload processing facility clean room high bay in Titusville, FL, on July 13, 2017. Launch on ULA Atlas V slated for August 2017 from Cape Canaveral Air Force Station, Fl. Credit: Ken Kremer/kenkremer.com
Carefully secured inside its shipping container, the TDRS-M satellite was transported on June 23 by a US Air Force cargo aircraft from Boeing’s El Segundo, California facility to Space Coast Regional Airport in Titusville, Florida, for preflight processing at Astrotech.
Watch for Ken’s onsite TDRS-M and space mission reports direct from the Kennedy Space Center and Cape Canaveral Air Force Station, Florida.
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
Artist's impression of Planet Nine, blocking out the Milky Way. The Sun is in the distance, with the orbit of Neptune shown as a ring. Credit: ESO/Tomruen/nagualdesign
In January of 2016, astronomers Mike Brown and Konstantin Batygin published the first evidence that there might be another planet in our Solar System. Known as “Planet 9”, this hypothetical body was estimated to be about 10 times as massive as Earth and to orbit that our Sun at an average distance of 700 AU. Since that time, multiple studies have been produced that either support or cast doubt on the existence of Planet 9.
While some argue that the orbits of certain Trans-Neptunian Objects (TNOs) are proof of Planet 9, others argue that these studies suffer from an observational bias. The latest study, which comes from a pair of astronomers from the Complutense University of Madrid (UCM), offers a fresh perspective that could settle the debate. Using a new technique that focuses on extreme TNOs (ETNOs), they believe the case for Planet 9 can be made.
Extreme Trans-Neptunian Objects are those that orbit our Sun at average distances greater than 150 AU, and therefore never cross Neptune’s orbit. As the UMC team indicate in their study, which was recently published in the Monthly Notices of the Royal Astronomical Society, the distances between the ETNOs nodes and the Sun may point the way towards Planet 9.
Artist’s impression of what the theoretical Planet 9 could look like. Credit: NASA
These nodes are the two points at which the orbit of a celestial body crosses the plane of the Solar System. It is at these points that the chances of interacting with other bodies in the Solar System is the greatest, and hence where ETNOs are most likely to experience a drastic change in their orbits (or a collision). By measuring where these nodes are, the team believed they could tell if the ETNOs are being perturbed by another object in the area.
“If there is nothing to perturb them, the nodes of these extreme trans-Neptunian objects should be uniformly distributed, as there is nothing for them to avoid, but if there are one or more perturbers, two situations may arise. One possibility is that the ETNOs are stable, and in this case they would tend to have their nodes away from the path of possible perturbers, he adds, but if they are unstable they would behave as the comets that interact with Jupiter do, that is tending to have one of the nodes close to the orbit of the hypothetical perturber”.
For the sake of their research, Doctors Carlos and Raul de la Fuente Marcos conducted calculations and data mining to analyze the nodes of 28 ETNOs and 24 extreme Centaurs (which also orbit the Sun at average distances of more than 150 AUs). What they noticed was that these two populations became clustered at certain distances from the Sun, and also noted a correlation between the positions of the nodes and the inclination of the objects.
Animated diagram showing the spacing of the Solar Systems planet’s, the unusually closely spaced orbits of six of the most distant KBOs, and the possible “Planet 9”. Credit: Caltech/nagualdesign
This latter find was especially unexpected, and led them to conclude that the orbits of these populations were being affected by the presence of another body – much in the same way that the orbits of comets within our Solar System have been found to be affected by the way they interact with Jupiter. As De la Fuente Marcos emphasized:
“Assuming that the ETNOs are dynamically similar to the comets that interact with Jupiter, we interpret these results as signs of the presence of a planet that is actively interacting with them in a range of distances from 300 to 400 AU. We believe that what we are seeing here cannot be attributed to the presence of observational bias”.
As already mentioned, previous studies that have challenged the existence of Planet 9 cited how the study of TNOs have suffered from an observational bias. Basically, they have claimed that these studies made systematic errors in how they calculated the orientations in the orbits of TNOs, in large part because they had all been directed towards the same region of the sky.
By looking at the nodal distances of ETNOs, which depend on the size and shape of their orbits, this most recent study offers the first evidence of Planet 9’s existence that is relatively free of this bias. At the moment, only 28 ETNOs are known, but the authors are confident that the discovery of more – and the analysis of their nodes – will confirm their observations and place further constraints on the orbit of Planet 9.
A planetary mass object the size of Mars would be sufficient to produce the observed perturbations in the distant Kuiper Belt. Credit: Heather Roper/LPL
In addition, the pair of astronomers offered some thoughts on recent work that has suggested the possible existence of a Planet 10. While their study does not take into account the existence of a Mars-sized body – which is said to be responsible for an observable “warp” in the Kuiper Belt – they acknowledge that there is compelling evidence that such a planet-sized body exists. As de la Fuente Marcos said:
“Given the current definition of planet, this other mysterious object may not be a true planet, even if it has a size similar to that of the Earth, as it could be surrounded by huge asteroids or dwarf planets. In any case, we are convinced that Volk and Malhotra’s work has found solid evidence of the presence of a massive body beyond the so-called Kuiper Cliff, the furthest point of the trans-Neptunian belt, at some 50 AU from the Sun, and we hope to be able to present soon a new work which also supports its existence”.
It seems that the outer Solar System is getting more crowded with every passing year. And these planets, if and when they are confirmed, are likely to trigger another debate about which Solar bodies are rightly designated as planets and which ones aren’t. If you thought the “planetary debate” was controversial and divisive before, I recommend staying away from astronomy forums in the coming years!
