A new study has offered a new take on the Fermi Paradox - alien civilizations are not visible to us because they are sleeping. Credit and Copyright: Kevin M. Gill
When you consider that age of the Universe – 13.8 billion years by our most recent counts – and that which is “observable” to us measures about 93 billion light-years in diameter, you begin to wonder why we haven’t found signs of extra-terrestrial intelligence (ETI) beyond our Solar System. To paraphrase Enrico Fermi, the 20th-century physicists who advanced the famous Fermi Paradox – “where the heck are all the aliens?”
Naturally, Fermi’s Paradox has attracted a lot of theoretical explanations over the years – which include ETI being very rare, humanity being early to the Universe, and the aliens being extinct! But a new study by a team of scientists from the Future of Humanity Institute (FHI) offers a different take on this age-old paradox. According to their study, the key to answering this question is to consider the possibility that the aliens are engaged in “aestivation”.
Beyond the Solar System’s Main Asteroid Belt lies the realm of the giants. It is here, staring with Jupiter and extending to Neptune, that the largest planets in the Solar System are located. Appropriately named “gas giants” because of their composition, these planets dwarf the rocky (terrestrial) planets of the inner Solar System many times over.
Just take a look at Saturn, the gas giant that takes its name from the Roman god of agriculture, and the second largest planet in the Solar System (behind Jupiter). In addition to its beautiful ring system and its large system of moons, this planet is renowned for its incredible size. Just how big is this planet? Well that depends on what your frame of reference is.
Diameter:
First let’s consider how large Saturn is from one end to the other – i.e. it’s diameter. The equatorial diameter of Saturn is 120,536 km ± 8 km (74,898 ± 5 mi) – or the equivalent of almost 9.5 Earths. However, as with all planets, their is a difference between the equatorial vs. the polar diameter. This difference is due to the flattening the planet experiences at the poles, which is caused by the planet’s rapid rotation.
Like all the giant planets, Saturn is many times the size of Earth and the other rocky planets. Credit: NASA/JPL-Caltech/Space Science Institute.
The poles are about 5,904 km closer to the center of Saturn than points on the equator. As a result, Saturn’s polar radius is about 108,728 ± 20 km (67,560 ± 12 mi) – or the equivalent of 8.5 Earths. That’s a pretty big difference, and you can actually see that Saturn looks a little squashed in pictures. Just for comparison, the equatorial diameter of Saturn is 9.4 times bigger than Earth, and it’s about 84% the diameter of Jupiter.
Volume and Surface Area:
In terms of volume and surface area, the numbers get even more impressive! For starters, the surface area of Saturn is 42.7 billion km² (16.5 billion sq miles), which works out to about 83.7 times the surface area of Earth. That’s smaller than Jupiter though, being only 68.7% of Jupiter’s surface area. Still, that is pretty astounding when put into perspective.
On the other hand, Saturn has a volume of 827.13 trillion km³ (198.44 trillion cubic miles), which effectively means you could fit Earth inside of it 763 times over and still have room enough for about twenty Moons! Again, Jupiter has it beat since Saturn has only 57.8% the volume of Jupiter. It’s big, but Jupiter is just that much bigger.
Mass and Density:
What about mass? Of course Saturn is much, much, MUCH more massive than Earth. In fact, it’s mass has been estimated to be a whopping 568,360,000 trillion trillion kg (1,253,000,000 trillion trillion lbs) – which works out to 95 times the mass of Earth. Granted, that only works out to about 30% the mass of Jupiter, but that’s still a staggering amount of matter.
Diagram of Saturn’s interior. Credit: Kelvinsong/Wikipedia Commons
Looking at the numbers, you may notice that this seems like a bit of a discrepancy. If you could actually fit 763 Earth-sized planets inside Saturn with room to spare, how is it that it is only 95 times Earth’s mass? The answer to that has to do with density. Since Saturn is a gas giant, its matter is distributed less densely than a rocky planet’s.
Whereas Earth has a density of 5.514 g/cm³ (or 0.1992 lb per cubic inch), Saturn’s density is only 0.687 g/cm3 (0.0248 lb/cu in). Like all gas giants, Saturn’s is made up largely of gases that exist under varying degrees of pressure. Whereas the density increases considerably the deeper one goes into Saturn’s interior, the overall density is less than that of water – 1 g/cm³ (0.0361273 lb/cu in).
Yes, Saturn is quite the behemoth. And yet, ongoing investigations into extra-solar planets are revealing that even it and its big brother Jupiter can be beaten in the size department. In fact, thanks to the Kepler mission and other exoplanet surveys, astronomers have found a plethora of “Super-Jupiters” in the cosmos, which refers to planets that are up to 80 times the mass of Jupiter.
I guess the takeaway from this is that there’s always a bigger planet out there. So watch your step and remember not to throw your weight (or mass or volume) around!
Pleiades stars. Image: NASA, ESA, AURA/Caltech, Palomar Observatory. Credit: D. Soderblom and E. Nelan (STScI), F. Benedict and B. Arthur (U. Texas), and B. Jones (Lick Obs.)
Welcome back to Messier Monday! In our ongoing tribute to the great Tammy Plotner, we take a look at the universally-renowned cluster known for its seven major points of light – The Pleiades Cluster!
During the 18th century, famed French astronomer Charles Messier noted the presence of several “nebulous objects” in the night sky. Having originally mistaken them for comets, he began compiling a list of them so that others would not make the same mistake he did. In time, this list (known as the Messier Catalog) would come to include 100 of the most fabulous objects in the night sky.
One of these is the famous Pleiades Cluster, also known as the Seven Sisters (and countless other names). An open star cluster located approximately 390 to 456 light years from Earth in the constellation of Taurus, this cluster is dominated by very bright, hot blue stars. Being both bright and of one of the nearest star clusters to Earth, this cluster is easily visible to the naked eye in the night sky.
Description:
The nine brightest stars of the Pleiades are named for the Seven Sisters of Greek mythology: Sterope, Merope, Electra, Maia, Taygete, Celaeno, and Alcyone, along with their parents Atlas and Pleione. To the X-ray telescopes on board the orbiting ROSAT observatory, the cluster also presents an impressive, but slightly altered, appearance.
An optical image of the Pleiades. Credit: NOAO/AURA/NSF
This false color image was produced from ROSAT observations by translating different X-ray energy bands to visual colors – the lowest energies are shown in red, medium in green, and highest energies in blue. (The green boxes mark the position of the seven brightest visual stars.)
The Pleiades stars seen in X-rays have extremely hot, tenuous outer atmospheres called coronas and the range of colors corresponds to different coronal temperatures. This helps to determine mass and the presence of brown dwarf stars within Messier 45. As Greg Ushomirsky (et al) said in a 1998 study:
“We present an analytic calculation of the thermonuclear depletion of the light elements lithium, beryllium, and boron in fully convective, low-mass stars. Under the presumption that the pre-main-sequence star is always fully mixed during contraction, we find that the burning of these rare light elements can be computed analytically, even when the star is degenerate. Using the effective temperature as a free parameter, we constrain the properties of low-mass stars from observational data, independently of the uncertainties associated with modeling their atmospheres and convection. Our analytic solution explains the dependence of the age at a given level of elemental depletion on the stellar effective temperature, nuclear cross sections, and chemical composition. These results are also useful as benchmarks to those constructing full stellar models. Most importantly, our results allow observers to translate lithium nondetections in young cluster members into a model-independent minimum age for that cluster. Using this procedure, we have found lower limits to the ages of the Pleiades (100 Myr) and Alpha Persei (60 Myr) clusters. Dating an open cluster using low-mass stars is also independent of techniques that fit upper main-sequence evolution. Comparison of these methods provides crucial information on the amount of convective overshooting (or rotationally induced mixing) that occurs during core hydrogen burning in the 5-10 Mo stars typically at the main-sequence turnoff for these clusters.”
As one of the closest of star clusters to our solar system, M45 is dominated by hot blue stars that have only formed within the last 100 million years. Alongside Maia is a reflection nebula discovered by Tempel faint nebula which accompanies Merope was discovered by master observer E.E. Barnard. These were first believed to be left over from the formation of the cluster.
Messier 45. Credit: Boris Stromar
However, it didn’t take many years of observation of proper motion for astronomers to realize the Pleiades were actually moving through a cloud of interstellar dust. While this pleasing blue group is still only 440 light years away, it only has about another 250 million years left before tidal interactions will tear it apart. By then, its relative motion will have carried it from the constellation of Taurus to the southern portion of Orion!
Of course, many observers aren’t quite sure if they are seeing the nebulosity in M45 or not. Chances are, if you’re seeing what appears to be a “fog” around the bright stars – you’re on it. Only large aperture or photography reveals the full extent of the reflection nebula… and there’s a whole lot of scientific reasons for it. Said Steven Gibson (et al) in a 2003 study:
“The scattering geometry analysis is complicated by the blending of light from many stars and the likely presence of more than one scattering layer. Despite these complications, we conclude that most of the scattered light comes from dust in front of the stars in at least two scattering layers, one far in front and extensive, the other nearer the stars and confined to areas of heavy nebulosity. The first layer can be approximated as an optically thin, foreground slab whose line-of-sight separation from the stars averages ~0.7 pc. The second layer is also optically thin in most locations and may lie at less than half the separation of the first layer, perhaps with some material among or behind the stars. The association of nebulosity peripheral to the main condensation around the brightest stars is not clear. Models with standard grain properties cannot account for the faintness of the scattered UV light relative to the optical. Some combination of significant changes in grain model albedo and phase function asymmetry values is required. Our best-performing model has a UV albedo of 0.22+/-0.07 and a scattering asymmetry of 0.74+/-0.06. Hypothetical optically thick dust clumps missed by interstellar sight line measurements have little effect on the nebular colors but might shift the interpretation of our derived scattering properties from individual grains to the bulk medium.”
Since the Pleaides really is close to our solar system, have astronomers been able to detect anything within its boundaries that has surprised them? The answer is yes. according to a 1998 study by E.L. Martin:
“We present the discovery of an object in the Pleiades open cluster, named Teide 2, with optical and infrared photometry that places it on the cluster sequence slightly below the expected substellar mass limit. We have obtained low- and high-resolution spectra that allow us to determine its spectral type (M6), radial velocity, and rotational broadening and to detect H? in emission and Li I in absorption. All the observed properties strongly support the membership of Teide 2 in the Pleiades. This object has an important role in defining the reappearance of lithium below the substellar limit in the Pleiades.”
The M45 cluster. Credit: Wikipedia Commons/Did23
And what star is that? One cataloged as known as HD 23514, which has a mass and luminosity a bit greater than our Sun. But it’s a star surrounded by an extraordinary number of hot dust particles. “Unusually massive amounts of dust, as seen at the Pleiades and Aries stars, cannot be primordial but rather must be the second-generation debris generated by collisions of large objects,” said Song, “”Collisions between comets or asteroids wouldn’t produce anywhere near the amount of dust we are seeing.”
The astronomers analyzed emissions from countless microscopic dust particles and concluded that the most likely explanation is that the particles are debris from the violent collision of planets or planetary embryos. Song calls the dust particles the “building blocks of planets,” which can accumulate into comets and small asteroid-size bodies and then clump together to form planetary embryos, eventually becoming full-fledged planets.
“In the process of creating rocky, terrestrial planets, some objects collide and grow into planets, while others shatter into dust,” Song said. “We are seeing that dust.”
History of Observation:
The recognition of the Pleiades dates back to antiquity, and its stars are known by many names in many cultures. The Greeks and Romans referred to them as the “Starry Seven,” the “Net of Stars,” “The Seven Virgins,” “The Daughters of Pleione,” and even “The Children of Atlas.” The Egyptians referred to them as “The Stars of Athyr;” the Germans as “Siebengestiren” (the Seven Stars); the Russians as “Baba” after Baba Yaga – the witch who flew through the skies on her fiery broom.
The Pleiades by Elihu Vedder (1885). Credit: Metropolitan Museum of Art, New York City.
The Japanese call them “Subaru;” Norsemen saw them as packs of dogs; and the Tongans as “Matarii” (the Little Eyes). American Indians viewed the Pleiades as seven maidens placed high upon a tower to protect them from the claws of giant bears, and even Tolkien immortalized the star group in The Hobbit as “Remmirath.” The Pleiades were even mentioned in the Bible! So, you see, no matter where we look in our “starry” history, this cluster of seven bright stars has been part of it.
Charles Messier would log it on March 4, 1769 where his only comment would be: “Cluster of stars known by the name Pleiades: the position reported is that of the star Alcyone.” Even though historic astronomers did little more than comment on M45’s presence, we’re still glad the Charles logged it – for it never received another “official” catalog designation!
Locating Messier 45:
Most normally the Pleiades are easily found with the unaided eye as a very visible cluster of stars about a hand span northwest of Orion. However, if sky conditions are bright, M45 might be a little more difficult to spot. If so, look for bright, red star Aldebaran and set your sights about 10 degrees (an average fist width) northwest.
It will show very easily in any size optics and under virtually any conditions – except for clouds and daylight! Messier 45’s large size makes it an ideal candidate for binoculars, where it will cover about half the average field of view. When using a telescope, chose the least amount of magnification possible to see the entire cluster and use higher magnification to study individual stars.
The location of the Centaurus constellation in the southern sky. Credit: IAU/Sky & Telescope magazine/Roger Sinnott & Rick Fienberg
And as always, here are the quick facts on this Messier Object to help you get started:
Object Name: Messier 45 Alternative Designations: M45, the Pleiades, Seven Sisters, Subaru Object Type: Open Galactic Star Cluster, Reflection Nebula Constellation: Taurus Right Ascension: 03 : 47.0 (h:m) Declination: +24 : 07 (deg:m) Distance: 0.44 (kly) Visual Brightness: 1.6 (mag) Apparent Dimension: 110.0 (arc min)
The NICER payload, shown here on the outside of the International Space Station. Credit: NASA
When a large star undergoes gravitational collapse near the end of its lifespan, a neutron star is often the result. This is what remains after the outer layers of the star have been blown off in a massive explosion (i.e. a supernova) and the core has compressed to extreme density. Afterwards, the star’s rotation rate increases considerably, and where they emit beams of electromagnetic radiation, they become “pulsars”.
And now, 50 years after they were first discovered by British astrophysicist Jocelyn Bell, the first mission devoted to the study of these objects is about to be mounted. It is known as the Neutron Star Interior Composition Explorer (NICER), a two-part experiment that will be deployed to the International Space Station this summer. If all goes well, this platform will shed light on one of the greatest astronomical mysteries, and test out new technologies.
Astronomers have been studying neutron stars for almost a century, which have yielded some very precise measurements of their masses and radii. However, what actually transpires in the interior of a neutron star remains an enduring mystery. While numerous models have been advanced that describe the physics governing their interiors, it is still unclear how matter would behave under these types of conditions.
Not surprising, since neutron stars typically hold about 1.4 times the mass of our Sun (or 460,000 times the mass of the Earth) within a volume of space that is the size of a city. This kind of situation, where a considerable amount of matter is packed into a very small volume – resulting in crushing gravity and an incredible matter density – is not seen anywhere else in the Universe.
As Keith Gendreau, a scientist at NASA’s Goddard Space Flight Center, explained in a recent NASA press statement:
“The nature of matter under these conditions is a decades-old unsolved problem. Theory has advanced a host of models to describe the physics governing the interiors of neutron stars. With NICER, we can finally test these theories with precise observations.”
NICE was developed by NASA’s Goddard Space Flight Center with the assistance of the Massachusetts Institute of Technology (MIT), the Naval Research Laboratory, and universities across the U.S. and Canada. It consists of a refrigerator-sized apparatus that contains 56 X-ray telescopes and silicon detectors. Though it was originally intended to be deployed late in 2016, a launch window did not become available until this year.
Once installed as an external payload aboard the ISS, it will gather data on neutron stars (mainly pulsars) over an 18-month period by observing neutron stars in the X-ray band. Even though these stars emit radiation across the spectrum, X-ray observations are believed to be the most promising when it comes to revealing things about their structure and various high-energy phenomena associated with them.
SEXTANT will demonstrate a GPS-like absolute position determination capability by observing millisecond pulsars. Credit: NASA
These include starquakes, thermonuclear explosions, and the most powerful magnetic fields known in the Universe. To do this, NICER will collect X-rays generated from these stars’ magnetic fields and magnetic poles. This is key, since it is at the poles that the strength of a neutron star’s magnetic fields causes particles to be trapped and rain down on the surface, which produces X-rays.
In pulsars, it is these intense magnetic fields which cause energetic particles to become focused beams of radiation. These beams are what give pulsars their name, as they appear like flashes thanks to the star’s rotation (giving them their “lighthouse”-like appearance). As physicists have observed, these pulsations are predictable, and can therefore be used the same way atomic-clocks and Global Positioning System are here on Earth.
While the primary goal of NICER is science, it also offers the possibility of testing new forms of technology. For instance, the instrument will be used to conduct the first-ever demonstration of autonomous X-ray pulsar-based navigation. As part of the Station Explorer for X-ray Timing and Navigation Technology (SEXTANT), the team will use NICER’s telescopes to detect the X-ray beams generated by pulsars to estimate the arrival times of their pulses.
The team will then use specifically-designed algorithms to create an on-board navigation solution. In the future, interstellar spaceships could theoretically rely on this to calculate their location autonomously. This wold allow them to find their way in space without having to rely on NASA’s Deep Space Network (DSN), which is considered to be the most sensitive telecommunications system in the world.
Beyond navigation, the NICER project also hopes to conduct the first-ever test of the viability of X-ray based-communications (XCOM). By using X-rays to send and receive data (in the same way we currently use radio waves), spacecraft could transmit data at the rate of gigabits per second over interplanetary distances. Such a capacity could revolutionize the way we communicate with crewed missions, rover and orbiters.
Central to both demonstrations is the Modulated X-ray Source (MXS), which the NICER team developed to calibrate the payload’s detectors and test the navigation algorithms. Generating X-rays with rapidly varying intensity (by switching on and off many times per second), this device will simulate a neutron star’s pulsations. As Gendreau explained:
“This is a very interesting experiment that we’re doing on the space station. We’ve had a lot of great support from the science and space technology folks at NASA Headquarters. They have helped us advance the technologies that make NICER possible as well as those that NICER will demonstrate. The mission is blazing trails on several different levels.”
It is hoped that the MXS will be ready to ship to the station sometime next year; at which time, navigation and communication demonstrations could begin. And it is expected that before July 25th, which will mark the 50th anniversary of Bell’s discovery, the team will have collected enough data to present findings at scientific conferences scheduled for later this year.
If successful, NICER could revolutionize our understanding of how neutron stars (and how matter behaves in a super-dense state) behaves. This knowledge could also help us to understand other cosmological mysteries such as black holes. On top of that, X-ray communications and navigation could revolutionize space exploration and travel as we know it. In addition to providing greater returns from robotic missions located closer to home, it could also enable more lucrative missions to locations in the outer Solar System and even beyond.
Blastoff of SpaceX Falcon 9 rocket from Launch Complex 39A at the Kennedy Space Center at 5:07 p.m. EDT on June 3, 2017, on Dragon CRS-11 resupply mission to the International Space Station (ISS) for NASA. Credit: Ken Kremer/kenkremer.com
Blastoff of SpaceX Falcon 9 rocket from Launch Complex 39A at the Kennedy Space Center) at 5:07 p.m. EDT on June 3, 2017, on Dragon CRS-11 resupply mission to the International Space Station (ISS) for NASA. Credit: Ken Kremer/kenkremer.com
Nearly simultaneously the first stage booster accomplished another heart stopping and stupendous ground landing back at the Cape accompanied by multiple shockingly loud sonic booms screeching out dozens of miles (km) in all directions across the space coast region.
SpaceX Falcon 9 booster deploys quartet of landing legs moments before precision propulsive ground touchdown at Landing Zone 1 on Canaveral Air Force Station barely nine minutes after liftoff from Launch Complex 39A on 3 June 2017 from the Kennedy Space Center in Florida on the Dragon CRS-11 resupply mission to the International Space Station for NASA. Credit: Ken Kremer/Kenkremer.com
Liftoff of the SpaceX Falcon 9 rocket carrying the unmanned Dragon cargo freighter from seaside Launch Complex 39A at KSC in Florida took place during an instantaneous launch window at 5:07 p.m. EDT Saturday, June 3, after a predicted downpour held off just long enough for the SpaceX launch team to get the rocket safely off the ground.
The launch took place after a 48 hour scrub from Thursday June 1 forced by stormy weather and lightning strikes came within 10 miles of pad 39A less than 30 minutes from the planned liftoff time.
The backup crew of 40 new micestonauts are also aboard for a first of its kind osteoporosis science study – that seeks to stem the loss of bone density afflicting millions of people on Earth and astronauts crews in space by testing an experimental drug called NELL-1. The 40 originally designated mice lost their coveted slot and were swapped out Friday due to the scrub.
The 213-foot-tall (65-meter-tall) SpaceX Falcon 9 roared to life off pad 39A upon ignition of the 9 Merlin 1 D first stage engines generating 1.7 million pounds of liftoff thrust and successfully delivered the Dragon bolted on top to low Earth orbit on course for the space station and jam packed with three tons of essential cargo.
Loading of the densified liquid oxygen and RP-1 propellants into the Falcon 9 first and second stages starting about 70 minutes prior to ignition. Everything went off without a hitch.
Final descent of the SpaceX Falcon 9 1st stage landing as seen from the NASA Causeway under heavily overcast skies after Jun 3, 2017 launch from pad 39A at the Kennedy Space Center. The booster successfully soft landed upright at Landing Zone-1 (LZ-1) accompanied by multiple sonic booms at Cape Canaveral Air Force Station, Florida, about 8 minutes after launch to the International Space Station (ISS). Note SpaceX logo lettering visible on booster skin. Credit: Ken Kremer/kenkremer.com
Dragon reached its preliminary orbit 10 minutes after launch and deployed its power generating solar arrays. It now set out on a carefully choreographed series of thruster firings to reach the space station Monday morning.
Following stage separation at 2 min 25 sec after liftoff, the first stage began a series of three burns (boostback, entry and landing) to carry out a precision propulsive ground landing back at Cape Canaveral Air Force Station, FL at Landing Zone-1 (LZ-1).
SpaceX Falcon 9 booster starts landing leg deployment moments before precision propulsive ground touchdown at Landing Zone 1 on Canaveral Air Force Station barely eight minutes after liftoff from pad 39A on 3 June 2017 from the Kennedy Space Center in Florida on the Dragon CRS-11 resupply mission to the International Space Station for NASA. Credit: Ken Kremer/Kenkremer.com
The 156-foot-tall (47-meter-tall) first stage successfully touched down upright at LZ-1 some 8 minutes after liftoff as I witnessed from the NASA Causeway and seen in photos from myself and colleagues herein.
LZ-1 is located about 9 miles (14 kilometers) south of the starting point at pad 39A.
Descent of SpaceX Falcon 9 1st stage towards Landing Zone-1 at Cape Canaveral after Jun 3, 2017 launch from pad 39A at the Kennedy Space Center. Credit: Julian Leek
Thus overall SpaceX has now successfully recovered 11 boosters; 5 by land and 6 by sea, over the past 18 months – in a feat straight out of science fiction but aimed at drastically slashing the cost of access to space as envisioned by SpaceX billionaire CEO and founder Elon Musk.
Another significant milestone for this flight is that it features the first reuse of a previously launched Dragon. It previously launched on the CRS-4 resupply mission.
The recycled Dragon has undergone some refurbishments to requalify it for flight but most of the structure is intact, according to SpaceX VP for Mission Assurance Hans Koenigsmann.
The 20-foot high, 12-foot-diameter Dragon is carrying almost 5,970 pounds of science experiments and research instruments, crew supplies, food water, clothing, hardware, gear and spare parts to the million pound orbiting laboratory complex. This will support over 62 of the 250 research investigations and experiments being conducted by Expedition 52 and 53 crew members.
See detailed CRS-11 cargo mission cargo below.
Blastoff of SpaceX Falcon 9 with reused Dragon CRS-11 cargo craft from Launch Complex 39A at NASA’s Kennedy Space Center in Florida at 5:07 p.m. on June 3, 2017. Credit: Julian Leek
Dragon CRS-11 marks SpaceX’s eleventh contracted commercial resupply services (CRS) mission to the International Space Station for NASA since 2012.
Falcon 9 streaked to orbit in spectacular fashion darting in and out of clouds for the hordes of onlookers and spectators who had gathered from around the globe to witness the spectacle of a rocket launch and booster landing first hand.
Recycled SpaceX Dragon CRS-11 cargo craft lifted off from Launch Complex 39A at NASA’s Kennedy Space Center in Florida at 5:07 p.m. June 3, 2017 carrying 3 tons of research equipment, cargo and supplies to Earth orbit and the International Space Station. Credit: Ken Kremer/kenkremer.com
Dragon is loaded with “major experiments that will look into the human body and out into the galaxy.”
The flight will deliver investigations and facilities that study neutron stars, osteoporosis, solar panels, tools for Earth-observation, and more.
The unpressurized trunk of the spacecraft also will transport 3 payloads for science and technology experiments and demonstrations.
The truck payloads include the Roll-Out Solar Array (ROSA) solar panels, the Multiple User System for Earth Sensing (MUSES) facility which hosts Earth-viewing instruments and tools for Earth-observation and equipment to study neutron stars with the Neutron Star Interior Composition Explorer (NICER) payload.
NICER is the first ever space mission to study the rapidly spinning neutron stars – the densest objects in the universe. The launch coincidentally comes nearly 50 years after they were discovered by British astrophysicist Jocelyn Bell.
A second objective of NICER involves the first space test attempting to use pulsars as navigation beacons through technology called Station Explorer for X-Ray Timing and Navigation (SEXTANT).
Roll Out Solar Array (ROSA) is among the science investigations launching on the next SpaceX commercial resupply flight to the International Space Station, targeted for June 1, 2017. Credits: Deployable Space Systems, Inc.
If all goes well, Dragon will arrive at the ISS 2 days after launch and be grappled by Expedition 52 astronauts Peggy Whitson and Jack Fischer using the 57.7 foot long (17.6 meter long) Canadian-built robotic arm.
They will berth Dragon at the Earth-facing port of the Harmony module.
NASA TV will begin covering the Dragon rendezvous and grappling activities starting at 8:30 a.m. Monday.
Dragon CRS-11 is SpaceX’s second contracted resupply mission to launch this year for NASA.
The prior SpaceX cargo ship launched on Feb 19, 2017 on the CRS-10 mission to the space station. CRS-10 is further noteworthy as being the first SpaceX launch of a Falcon 9 from NASA’s historic pad 39A.
Overall CRS-11 marks the 100th launch from pad 39A and the sixth SpaceX launch from this pad.
SpaceX leased pad 39A from NASA in 2014 and after refurbishments placed the pad back in service this year for the first time since the retirement of the space shuttles in 2011. To date this is the sixth SpaceX launch from this pad.
Previous launches include 11 Apollo flights, the launch of the unmanned Skylab in 1973, 82 shuttle flights and five SpaceX launches.
June 3, 2017 liftoff of SpaceX Falcon 9 with reused Dragon CRS-11 cargo craft from Launch Complex 39A at NASA’s Kennedy Space Center in Florida at 5:07 p.m. on June 3, 2017. Credit: Jeff Seibert
Cargo Manifest for CRS-11:
TOTAL CARGO: 5970.1 lbs. / 2708 kg
TOTAL PRESSURIZED CARGO WITH PACKAGING: 3761.1 lbs. / 1665 kg
• Science Investigations 2356.7 lbs. / 1069 kg
• Crew Supplies 533.5 lbs. / 242 kg
• Vehicle Hardware 438.7 lbs. / 199 kg
• Spacewalk Equipment 123.4 lbs. / 56 kg
• Computer Resources 59.4 lbs. / 27 kg
UNPRESSURIZED 2209.0 lbs. / 1002 kg
• Roll-Out Solar Array (ROSA) 716.5 lbs. / 325 kg
• Neutron Star Interior Composition Explorer (NICER) 820.1 lbs. / 372 kg
• Multiple User System for Earth Sensing (MUSES) 672.4 lbs. / 305 kg
Watch for Ken’s onsite CRS-11 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.
SpaceX Falcon 9 booster starts landing leg deployment moments before precision propulsive ground touchdown at Landing Zone 1 on Canaveral Air Force Station barely eight minutes after liftoff from pad 39A on 3 June 2017 from the Kennedy Space Center in Florida on the Dragon CRS-11 resupply mission to the International Space Station for NASA. Credit: Ken Kremer/Kenkremer.com
Launch of SpaceX Falcon 9 with reused Dragon CRS-11 cargo craft from Launch Complex 39A at NASA’s Kennedy Space Center in Florida at 5:07 p.m. on June 3, 2017 as seen from the Countdown clock at the KSC Press Site. Credit: Jean Wright
Up close view of SpaceX Dragon CRS-11 resupply vessel atop Falcon 9 rocket and delivering 3 tons of science and supplies to the International Space Station (ISS) for NASA. Liftoff occurred 3 June 2017. Credit: Ken Kremer/Kenkremer.com
SpaceX Falcon 9 rocket goes erect to launch position atop Launch Complex 39A at the Kennedy Space Center on 1 Jun 2017 as seen the morning before later afternoon launch from inside from the pad perimeter. Liftoff of the CRS-11 resupply mission to the International Space Station (ISS) occurred 3 June 2017. Credit: Ken Kremer/Kenkremer.com
Stratolaunch Systems just conducted their first rollout of the Roc aircraft to begin fueling tests. Credit: Stratolaunch Systems
In 2011, Microsoft co-founder Paul G. Allen and Scaled Composites founder Burt Rutan announced the launch of their private space venture. Known as Stratolaunch Systems, this Seattle-based company was founded with the intention of developing air-launch-to-orbit systems. Similar to Virgin Galactic’s SpaceShipTwo, this concept involves a large air carrier flying rockets to launch altitude as cost-effective means of delivering small payloads to orbit.
On Thursday, May 31st, the company unveiled their launch vehicle, the Scaled Composites Model 351 (aka. the “Roc”). Consisting of two 747 hulls mated together, this aircraft is the the largest in the world – spanning 117 meters (385 ft) from one wingtip to the other and weighing 226,796 kg (500,000 lbs). This plane will make its first test flight in a few days time, and the company hopes to make its first commercial launch by 2019.
The rollout of the Roc – which took place at the company’s hangar facility at the Mojave Air and Space Port in California – was a media circus. In addition to being the first time that the public got to see the aircraft since construction began, the occasion marked the beginning of several tests which will take place over the coming days – including fueling tests, engine runs, taxi tests, and its first test flight.
Aerial view of the Roc aircraft, showing its massive 117 m (385 ft) wingspan. Credit: Stratolaunch Systems
“We’re excited to announce that Stratolaunch aircraft has reached a major milestone in its journey toward providing convenient, reliable, and routine access to low Earth orbit. Today, we’re moving the Stratolaunch aircraft out of the hangar – for the first time ever – to conduct aircraft fueling tests. This marks the completion of the initial aircraft construction phase and the beginning of the aircraft ground and flight testing phase.”
Measuring about 72.5 meters (238 ft) from nose to tail, the aircraft also stands 15.24 meters (50 ft) tall, measured from the ground to the top of the vertical tail. It has a maximum takeoff weight of 589,670 kg (1.3 million lbs), meaning that it is capable of airlifting payloads of up to 249,476 kg (550,000 lbs). These kinds of payloads mean that it will be capable of flying rockets and heavy space planes to launch altitude.
Last fall, the company announced their plan to conduct a launch using a single Orbital ATK Pegasus XL vehicle, a three-stage rocket used to deploy small satellites to Low-Earth Orbit (LEO). This agreement was part of a multi-year collaboration between the two companies, which would see the former combining their aircraft with the latter’s extensive air-launch experience.
Artist’s impression of the Roc aircraft, with a full loadout of three Pegasus rockets. Credit: Stratolaunch Systems
First unveiled in 1990, the Pegasus XL quickly established itself as a cost-effective means for launching small payloads to LEO. These typically would consist of small satellites weighing up to 443 kg (977 lbs) from beneath a NASA B-52 aircraft. Since then, the Pegasus has carried out 43 space launch missions and successfully placed a total of 94 satellites into orbit for various reasons – ranging from scientific research and communications to defense.
In time, the company plans to explore a wide range of launch vehicles that can provide flexibility in terms of missions and payloads. But in the meantime, they will be conducting ground and flight line testing from the Mojave Air and Space Port to ensure that Roc is capable of doing all it was designed for. If all goes well, they plan to make their first commercial launch by 2019.
“This marks a historic step in our work to achieve Paul G. Allen’s vision of normalizing access to low Earth orbit,” said Floyd. “It is proud day for us at Stratolaunch, for our partners at Scaled Composites, and for our founder Paul Allen. We have a lot of exciting activity ahead as we enter the testing process, and we look forward to sharing our progress during the coming months.”
One of the hallmarks of the commercial aerospace (aka. NewSpace) industry has been the development of cost-saving measures. Whereas companies like SpaceX and Blue Origin has looked to reusable rocket technology, other companies have sought to reduce costs with Single-Stage-to-Orbit (SSTO) rockets and plug-in payloads. Air-launch-to-orbit systems are just another way in which space is becoming more accessible.
And be sure to check out this video of the Roc’s unveiling:
Compared to a regular human, the Earth is enormous. And compared to the Earth, the Universe is really enormous. Like, maybe infinitely enormous.
And yet, Earth is the only place humans are allowed to own. You can buy a plot of land in the city or the country, but you can’t buy land on the Moon, on Mars or on Alpha Centauri.
It’s not that someone wouldn’t be willing to sell it to you. I could point you at a few locations on the internet where someone would be glad to exchange your “Earth money” for some property rights on the Moon. But I can also point you to a series of United Nations resolutions which clearly states that outer space should be free for everyone. Not even the worst rocky outcrop of Maxwell Montes on Venus, or the bottom of Valles Marineris on Mars can be bought or sold.
However, the ability to own property is one of the drivers of the modern economy. Most people either own land, or want to own land. And if humans do finally become a space faring civilization, somebody is going to want to own the property rights to chunks of space. They’re going to want the mining rights to extract resources from asteroids and comets.
We’re going to want to know, once and for all, can I buy the Moon?
Until the space age, the question was purely hypothetical. It was like asking if you could own dragons, or secure the mining rights to dreams. Just in case those become possible, my vote to both is no.
The Sputnik spacecraft stunned the world when it was launched into orbit on Oct. 4th, 1954. Credit: NASA
But when the first satellite was placed into orbit in 1957, things became a lot less hypothetical. Once multiple nations had reached orbitable capabilities, it became clear that some rules needed to be figured out – the Outer Space Treaty.
The first version of the treaty was signed by the US, Soviet Union and the United Kingdom back in 1967. They were mostly concerned with preventing the militarization of space. You’re not allowed to put nuclear weapons into space, you’re not allowed to detonate nuclear weapons on other planets. Seriously, if you’ve got plans and they relate to nuclear weapons, just, don’t.
Can’t kill killer asteroids with nukes. Credit: Los Alamos National Lab
Over the years, almost the entire world has signed onto the Outer Space Treaty. 106 countries are parties and another 24 have signed on, but haven’t fully ratified it yet.
In addition to all those nuclear weapons rules, the United Nations agreed on several other rules. In fact, its full name is, The Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies.
Here’s the relevant language:
Outer space, including the moon and other celestial bodies, is not subject to national appropriation by claim of sovereignty, by means of use or occupation, or by any other means.
No country can own the Moon. No country can own Jupiter. No country can own a tiny planet, off in the corner of the Andromeda Galaxy. And no citizens or companies from those countries can own any property either.
And so far, no country has tried to. Seriously, space exploration is incredibly difficult. We’ve only set foot on the Moon a couple of times, decades ago, and never returned.
But with all the recent developments, it looks like we might be getting closer to wondering if we can own dragons, or a nice acreage on Mars.
Perhaps the most interesting recent development is the creation of not one, not two, but three companies dedicated to mining resources from asteroids: Planetary Resources, Kepler Energy, and Deep Space Industries.
Just a single small asteroid could contain many useful minerals, and there could potentially be tens of billions of dollars in profit for anyone who can sink robotic mining shafts into them.
Asteroid mining concept. Credit: NASA/Denise Watt
The three different companies have their own plans on how they’re going to identify potential mining targets and extract resources, and I’m not going to go into all the details of what it would take to mine an asteroid in this video.
But according to the Outer Space Treaty, is it legal? The answer, is: probably.
The original treaty was actually pretty vague. It said that no country can claim sovereignty over a world in space, but that doesn’t mean we can’t utilize some of its resources. In fact, future missions to the Moon and Mars depend on astronauts “living off the land”, harvesting local resources like ice to make air, drinking water and rocket fuel. Or building structures out of Martian regolith.
Mining an entire asteroid for sweet sweet profit is just a difference of scale.
In order to provide some clarity, the United States passed the U.S. Commercial Space Launch Competitiveness Act of 2015. This gave details on how space tourism should work, and described how companies might mine minerals from space. The gist of the law is, if an American citizen can get their hands on materials from an asteroid, they own it, and they’re free to sell it.
The Interplanetary Transport System blasting off. Credit: SpaceX
As you know, SpaceX is planning to colonize Mars. Well, so far, their plans include building the most powerful rocket ever built, and hurling human beings at Mars, hundreds at a time. The first mission is expected to blast off in 2024, so this is quickly becoming a practical issue.
What are the legalities of colonizing Mars? Will you own a chunk of land when you stumble out of the Interplanetary Transport Ship out on the surface of Mars?
Right now, you can imagine the surface of Mars like a research station on Antarctica. If SpaceX, an American company, builds a colony on Mars, then it’s essentially US government property. Anything that happens within that colony is under the laws of the United States.
If a group of colonists from China, for example, set out on their own, they would be building a little piece of China. And no matter what kind of facility they build, nobody within the team actually owns their homes.
If you’re out on the surface, away from a base, everything reverts to international law. Watch out for space pirates!
The space pirates were everywhere. Monday suddenly got a lot more interesting. Credit: NASA/JSC/Pat Rawlings, SAIC
Under the treaty, every facility is obliged to provide access to anyone else out there, which means that members of one facility are free to visit any other facility. You can’t lock your door and keep anyone out.
In fact, if anyone’s in trouble, you’re legally bound to do everything you can (within reason) to lend your assistance.
The bottom line is that the current Outer Space Treaty is not exactly prepared for the future reality of the colonization of Mars. As more and more people reach the Red Planet, you’d expect they’re going to want to govern themselves. We’ve seen this play out time and time again on Earth, so it won’t be surprising when the Mars colonies band together to declare their separation from Earth.
That said, as long as they’re reliant on regular supplies from Earth, they won’t be able to fully declare their independence. As long as they have interests on Earth, our planet’s governments will be able to squeeze them and maintain their dominance.
Credit: NASA
Once a Mars colony is fully self sufficient, though, which Elon Musk estimates will occur by 1 million inhabitants, Earth will have to recognize a fully independent Mars.
Space law is going to be one of the most interesting aspects of the future of space exploration. It’s really the next frontier. Concepts which were purely theoretical are becoming more and more concrete, and lawyers will finally be the heroes we always knew they could be.
If you’ve always wanted to be an astronaut, but your parents have always wanted you to be a lawyer, now’s your chance to do both. An astronaut space lawyer. I’m just saying, it’s an option.
Artist's impression of merging binary black holes. Credit: LIGO/A. Simonnet.
A third gravitational wave has been detected by the Laser Interferometer Gravitational-wave Observatory (LIGO). An international team announced the detection today, while the event itself was detected on January 4th, 2017. Gravitational waves are ripples in space-time predicted by Albert Einstein over a century ago.
LIGO consists of two facilities: one in Hanford, Washington and one in Livingston, Louisiana. When LIGO announced its first gravitational wave back in February 2016 (detected in September 2015), it opened up a new window into astronomy. With this gravitational wave, the third one detected, that new window is getting larger. So far, all three waves detected have been created by the merging of black holes.
When the first gravitational wave was finally detected, over a hundred years after Einstein predicted it, it helped confirm Einstein’s description of space-time as an integrated continuum. It’s often said that it’s not a good idea to bet against Einstein, and this third detection just strengthens Einstein’s theory.
Like the previous two detections, this one was created by the merging of two black holes. These two were different sizes from each other; one was about 31.2 solar masses, and the other was about 19.4 solar masses. The combined 50 solar mass event caused the third wave, which is named GW170104. The black holes were about 3 billion light years away.
LIGO is showing us that their is a population of binary black holes out there. “Our handful of detections so far is revealing an intriguing black hole population we did not know existed until now,” said Northwestern’s Vicky Kalogera, a senior astrophysicist with the LIGO Scientific Collaboration (LSC), which conducts research related to the twin LIGO detectors, located in the U.S.
“Now we have three pairs of black holes, each pair ending their death spiral dance over millions or billions of years in some of the most powerful explosions in the universe. In astronomy, we say with three objects of the same type you have a class. We have a population, and we can do analysis.”
The Laser Interferometer Gravitational-Wave Observatory (LIGO)facility in Livingston, Louisiana. The other facility is located in Hanford, Washington. Image: LIGO
When we say that gravitational waves have opened up a new window on astronomy, that window opens onto black holes themselves. Beyond confirming Einstein’s predictions, and establishing a population of binary black holes, LIGO can characterize and measure those black holes. We can learn the holes’ masses and their spin characteristics.
“Once again, the black holes are heavy,“ said Shane Larson, of Northwestern University and Adler Planetarium in Chicago. “The first black holes LIGO detected were twice as heavy as we ever would have expected. Now we’ve all been churning our cranks trying to figure out all the interesting myriad ways we can imagine the universe making big and heavy black holes. And Northwestern is strong in this research area, so we are excited.”
This third finding strengthens the case for the existence of a new class of black holes: binary black holes that are locked in relationship with each other. It also shows that these objects can be larger than thought before LIGO detected them.
“It is remarkable that humans can put together a story and test it, for such strange and extreme events that took place billions of years ago and billions of light-years distant from us.” – David Shoemaker, MIT
“We have further confirmation of the existence of black holes that are heavier than 20 solar masses, objects we didn’t know existed before LIGO detected them,” said David Shoemaker of MIT, spokesperson for the LIGO Scientific Collaboration . “It is remarkable that humans can put together a story and test it, for such strange and extreme events that took place billions of years ago and billions of light-years distant from us.”
An artist’s impression of two merging black holes. Image: NASA/CXC/A. Hobart
“With the third confirmed detection of gravitational waves from the collision of two black holes, LIGO is establishing itself as a powerful observatory for revealing the dark side of the universe,” said David Reitze of Caltech, executive director of the LIGO Laboratory and a Northwestern alumnus. “While LIGO is uniquely suited to observing these types of events, we hope to see other types of astrophysical events soon, such as the violent collision of two neutron stars.”
A tell-tale chirping sound confirms the detection of a gravitational wave, and you can hear it described and explained here, on a Northwestern University podcast.
One of the Daya Bay detectors.
Roy Kaltschmidt, Lawrence Berkeley National Laboratory
It is no easy thing to search for signs of intelligent life beyond our Solar System. In addition to the incredible distances involved and the fact that we really only have indirect methods at our disposal, there is also the small problem of not knowing exactly what to look for. If intelligent life does exist beyond our Solar System, would they even communicate as we do, using radio transmitters and similar forms of technology?
Such has been the preoccupation of groups like the Search for Extra Terrestrial Intelligence (SETI) Institute and, more recently, organizations like Messaging Extraterrestrial Intelligence (METI) International. A non-profit dedicated to communicating with extra-terrestrial intelligence (ETI), the organization recently suggested that looking for neutrinos and other exotic particles could help us find signals as well.
First, some clarification should be made as to what SETI and METI are all about it and what sets them apart. The term METI was coined by Russian scientist Alexander Zaitsev, who sought to draw a distinction between SETI and METI. As he explained in a 2006 paper on the subject:
“The science known as SETI deals with searching for messages from aliens. METI science deals with the creation of messages to aliens. Thus, SETI and METI proponents have quite different perspectives. SETI scientists are in a position to address only the local question “does Active SETI make sense?” In other words, would it be reasonable, for SETI success, to transmit with the object of attracting ETI’s attention? In contrast to Active SETI, METI pursues not a local and lucrative impulse, but a more global and unselfish one – to overcome the Great Silence in the Universe, bringing to our extraterrestrial neighbors the long-expected annunciation ‘You are not alone!'”
One of the 42 dishes in the Allen Telescope Array that searches for signals from space. Credit: Seth Shostak/SETI Institute.
In short, METI looks for ways in which we might be able to contact aliens instead of waiting to hear from them. However, this does not mean that organizations like METI International are without ideas on how me might better listen to our (potential) alien neighbors. After all, communication goes beyond mere messages, and also requires that a medium exist with which to convey the message.
Such is the recommendation put forth by Dr. Morris Jones, a space analyst and writer who serves on the METI advisory council. In a recent article published on METI International’s website, he addressed the two main challenges when it comes to looking for ETI. On the one hand, you have the need for multiple methodologies to increase the odds of finding something. But as he indicates, there’s also the problem of knowing what to look for:
“We are not really sure of how extraterrestrials would communicate with us. Would they use radio waves, lasers, or something more exotic? Perhaps the universe is awash in extraterrestrial signals that we cannot even receive. SETI and METI practitioners spend a lot of time wondering how a message would be encoded in terms of language and content. It’s also important to consider the medium of transmission.”
In the past, says Jones, SETI searches were based on radio astronomy because that was the only practical means of doing so. Since then, efforts have expanded to include optical telescopes and the search for laser signals. This is due to the fact that in the past few decades, human beings have developed the technology to use laser for the sake of communications.
An artist’s illustration of a light-sail powered by a radio beam (red) generated on the surface of a planet. Could the part of the beam that misses the sail be our mysterious Fast Radio Bursts? Image Credit: M. Weiss/CfA
In a 2016 SETI paper, Dr. Philip Lubin of the University of California, Santa Barbara, explained how the development of directed-energy propulsion could help us search for evidence of aliens. As one of the scientific minds behind Breakthrough Starshot – a laser-driven lightsail that would be fast enough to make the trip to Alpha Centauri in just 20 years – he believes it’s a safe bet that ETI could be using similar technology to travel or communicate.
In addition, Dr. Avi Loeb from the Harvard-Smithsonian Center for Astrophysics (also one of the minds behind Starshot) has also suggested that fast-radio bursts (FRBs) could be evidence of alien activity. FRBs have been a subject of fascination to scientists since they were first detected in 2007 (the “Lorimer Burst“), and could also be a sign of alien communications or a means of propulsion.
Another means involves searching for artefacts – i.e. looking for evidence of physical infrastructure in other star systems. Case in point, since 2015, astronomers have been seeking to determine what is responsible for the periodic dimming of KIC 8462852 (aka. Tabby’s Star). Whereas most studies have sought to explain this in terms of natural causes, others have suggested it could be evidence of an alien megastructure.
To this array of search methods, Dr. Jones offers a few other possibilities. One way is to look for neutrinos, a type of subatomic particle that is produced by the decay of radioactive elements and interacts with matter very weakly. This allows them to pass through solid matter and also makes them very difficult to detect. Neutrinos are produced in large quantities by our Sun and astronomical sources, but they can also be produced artificially by nuclear reactors.
Ever since it was first announced in 2015, there has been speculation as to what could account for the dimming of KIC 8462852. Credit: SentientDevelopments.com
These, claims Jones, could be used for the sake of communications. The only problem is that looking for them would require some specialized equipment. Currently, all means of detecting neutrinos involve expensive facilities that have to be built either underground or in extremely isolated locations to ensure that they are not subject to any kind of electromagnetic interference.
Another possibility is searching for evidence of communications that rely on gravitational waves. Predicted by Einstein’s Theory of General Relativity, the first detection of these mysterious waves was first made in February 2016. And in the coming years and decades, it is expected that gravitational wave observatories will be established so the presence of these “ripples” in spacetime can be visualized.
However, compared to neutrinos, Jones admits that this seems like a long shot. “It’s hard to conceive with our current grasp of physics,” he writes. “They are extremely difficult to generate at a detectable level. You would need abilities similar to those of superheroes, and be able to smash neutron stars and black holes together at will. There are probably easier ways to get a message across the stars.”
Breakthrough Listen will monitor the 1 million closest stars to Earth over a ten year period. Credit: Breakthrough Initiatives
Beyond these, there is the even more exotic possibility of “Zeta Rays”, which Dr. Jones is not prepared to rule out. Basically, “Zeta Rays” is a term used by physicists to describe physics that go beyond the Standard Model. As scientists are currently looking for evidence of new particles with the Large Hadron Collider and other particle accelerators, it stands to reason that anything they discover will be the added to the SETI and METI search manifest.
But could such physics entail new forms of communication? Hard to say, but definitely worth considering. After all, the physics that power our current technology certainly existed before we did. Or as Jones put it:,
“Is it possible to transmit with something better than we already have? Until we know a lot more physics, we just won’t know. Humanity in the twenty-first century could be like an isolated tribe in the Amazon jungle a century ago, unaware that the air around them was filled with radio signals. SETI uses the science and technology provided to us by other disciplines. Thus, we must wait until physics itself makes some more major breakthroughs. Only then can we consider such exotic methods of searching. We think a lot about the message. But we should also think about the medium.”
Other projects that are dedicated to METI include Breakthrough Listen, a ten-year initiative launched by Breakthrough Initiatives to conduct the largest survey to date for extraterrestrial communications – encompassing the 1,000,000 closest stars and 100 closest galaxies. Back in April of 2017, the scientists behind this project shared their analysis of the first year of Listen data. No definitive results have been announced yet, but they are just getting started!
Ever since Drake proposed his famous equation, human beings have eagerly sought to find evidence of extra-terrestrial intelligence. Unfortunately, all of our efforts have been haunted by Fermi’s equally-famous paradox! But of course, as space exploration goes, we’ve really only begun to scratch the surface of our Universe. And the only way we can ever expect to find evidence of intelligent life out there is to keep looking.
And with greater knowledge and increasingly sophisticated methods at our disposal, we can be sure that if intelligent life is out there somewhere, we will find it eventually. One can always hope, right? And be sure to check out this video of Dr. Jones 2014 presentation at the SETI Institute, titled “A Journalistic Perspective on SETI-Related Message Composition“:
This artist's impression shows a star crossing the event horizon of a supermassive black hole located in the center of a galaxy. The black hole is so large and massive that tidal effects on the star are negligible, and the star is swallowed whole. Image: Mark A. Garlick/CfA
At the center of our Milky Way galaxy dwells a behemoth. An object so massive that nothing can escape its gravitational pull, not even light. In fact, we think most galaxies have one of them. They are, of course, supermassive black holes.
Supermassive black holes are stars that have collapsed into a singularity. Einstein’s General Theory of Relativity predicted their existence. And these black holes are surrounded by what’s known as an event horizon, which is kind of like the point of no return for anything getting too close to the black hole. But nobody has actually proven the existence of the event horizon yet.
Some theorists think that something else might lie at the center of galaxies, a supermassive object event stranger than a supermassive black hole. Theorists think these objects have somehow avoided a black hole’s fate, and have not collapsed into a singularity. They would have no event horizon, and would have a solid surface instead.
“Our whole point here is to turn this idea of an event horizon into an experimental science, and find out if event horizons really do exist or not,” – Pawan Kumar Professor of Astrophysics, University of Texas at Austin.
A team of researchers at the University of Texas at Austin and Harvard University have tackled the problem. Wenbin Lu, Pawan Kumar, and Ramesh Narayan wanted to shed some light onto the event horizon problem. They wondered about the solid surface object, and what would happen when an object like a star collided with it. They published their results in the Monthly Notices of the Royal Astronomical Society.
Artist’s conception of the event horizon of a black hole. Credit: Victor de Schwanberg/Science Photo Library
“Our whole point here is to turn this idea of an event horizon into an experimental science, and find out if event horizons really do exist or not,” said Pawan Kumar, Professor of Astrophysics at The University of Texas at Austin, in a press release.
Since a black hole is a star collapsed into a singularity, it has no surface area, and instead has an event horizon. But if the other theory turns out to be true, and the object has a solid surface instead of an event horizon, then any object colliding with it would be destroyed. If a star was to collide with this hard surface and be destroyed, the team surmised, then the gas from the star would enshroud the object and shine brightly for months, or even years.
This is the first in a sequence of two artist’s impressions that shows a huge, massive sphere in the center of a galaxy, rather than a supermassive black hole. Here a star moves towards and then smashes into the hard surface of the sphere, flinging out debris. The impact heats up the site of the collision. Image: Mark A. Garlick/CfA
In this second artist’s impression a huge sphere in the center of a galaxy is shown after a star has collided with it. Enormous amounts of heat and a dramatic increase in the brightness of the sphere are generated by this event. The lack of observation of such flares from the center of galaxies means that this hypothetical scenario is almost completely ruled out. Image: Mark A. Garlick/CfA
If that were the case, then the team knew what to look for. They also worked out how often this would happen.
“We estimated the rate of stars falling onto supermassive black holes,” Lu said in the same press release. “Nearly every galaxy has one. We only considered the most massive ones, which weigh about 100 million solar masses or more. There are about a million of them within a few billion light-years of Earth.”
Now they needed a way to search the sky for these objects, and they found it in the archives of the Pan-STARRS telescope. Pan-STARRS is a 1.8 meter telescope in Hawaii. That telescope recently completed a survey of half of the northern hemisphere of the sky. In that survey, Pan-STAARS spent 3.5 years looking for transient objects in the sky, objects that brighten and then fade. They searched the Pan-STARR archives for transient objects that had the signature they predicted from stars colliding with these supermassive, hard-surfaced objects.
The trio predicted that in the 3.5 year time-frame captured by the Pan-STAARS survey, 10 of these collisions would occur and should be represented in the data.
“It turns out it should have detected more than 10 of them, if the hard-surface theory is true.” – Wenbin Lu, Dept. of Astronomy, University of Texas at Austin.
“Given the rate of stars falling onto black holes and the number density of black holes in the nearby universe, we calculated how many such transients Pan-STARRS should have detected over a period of operation of 3.5 years. It turns out it should have detected more than 10 of them, if the hard-surface theory is true,” Lu said.
The team found none of the flare-ups they expected to see if the hard-surface theory is true.
“Our work implies that some, and perhaps all, black holes have event horizons…” – Ramesh Narayan, Harvard-Smithsonian Center for Astrophysics.
What might seem like a failure, isn’t one of course. Not for Einstein, anyway. This represents yet another successful test of Einstein’s Theory of General Relativity, showing that the event horizon predicted in his theory does seem to exist.
As for the team, they haven’t abandoned the idea yet. In fact, according to Pawan Kumar, Professor of Astrophysics, University of Texas at Austin, “Our motive is not so much to establish that there is a hard surface, but to push the boundary of knowledge and find concrete evidence that really, there is an event horizon around black holes.”
“General Relativity has passed another critical test.” – Ramesh Narayan, Harvard-Smithsonian Center for Astrophysics.
“Our work implies that some, and perhaps all, black holes have event horizons and that material really does disappear from the observable universe when pulled into these exotic objects, as we’ve expected for decades,” Narayan said. “General Relativity has passed another critical test.”
The team plans to continue to look for the flare-ups associated with the hard-surface theory. Their look into the Pan-STARRS data was just their first crack at it.
An artist’s illustration of the Large Synoptic Survey Telescope with a simulated night sky. The team hopes to use the LSST to further refine their search for hard-surface supermassive objects. Image: Todd Mason, Mason Productions Inc. / LSST Corporation
They’re hoping to improve their test with the upcoming Large Synoptic Survey Telescope (LSST) being built in Chile. The LSST is a wide field telescope that will capture images of the night sky every 20 seconds over a ten-year span. Every few nights, the LSST will give us an image of the entire available night sky. This will make the study of transient objects much easier and effective.
