Where are the Aliens? Interview With a SETI Researcher

 

Some future searches for alien civilizations will focus on potentially habitable planets, like in the Kepler 62 system, seen here in this artist illustration. Credit: NASA Ames/JPL-Caltech.

Yesterday the internet was abuzz with talk about UFOs and the Roswell incident, which took place 66 years ago this week.
Discovering life beyond Earth has always been considered by some to be the holy grail of science. However, no little green men or even measly microbes have been conclusively found. But this hasn’t dampened the enthusiasm among astronomers who are still searching the cosmos for signs of extra-terrestrial life.  The current leading search method uses giant radio dishes to scan the stars, listening for possible faint signals coming from distant civilizations.
National Geographic News caught up with SETI (Search for Extraterrestrial Intelligence)  radio astronomer, Andrew Siemion, who is based at the University of California at Berkeley, to chat about how astronomers listen for aliens.

What kind of alien signals are scientists looking for?
There are intentional signals – much like a lighthouse or a beacon – [that] can produce an emission intentionally designed to produce a signal so that other intelligent life know they exist.
Then there is leakage signal — akin to our aircraft radar, and TV broadcasts.  A signal like this, however, would have to be very powerful for us to be able to detect this right now from Earth.  For example, the farthest we could detect signals like what we are leaking right now with our current technology is probably at best only 1 light year out. [The nearest star to Earth is Proxima Centauri at 4.3 light years.]
However if we allow extraterrestrial (ET) telescopes to get large – say a radio telescope that has the diameter of the Earth – then they could detect very weak signals.
Many in the SETI community believe that the first signals we may detect will not be leakage signals but intentional ones designed to notify others of their presence.
But new telescopes are coming online soon, like the Square Kilometer Array, the largest radio telescope ever built in history. It will have 10 times the collecting area of the Arecibo radio telescope in Puerto Rico, and will be sensitive enough to ET signal leakage from 5 to 10 stars of the nearest stars.

Any region of the sky that current searches find particularly exciting?
In just the last two years NASA’s Kepler planet-hunting mission has taught us is that most stars have planets.  We are also learning that the habitable zones are much broader than what we [previously] thought.  We know there are lots of way to get the heat needed to keep water in its liquid form.  What this means is that we are really starting to expand our ideas about the kind of conditions that would be necessary for life to emerge.   At SETI today, we not only do all-sky surveys, but  more and more targeted searches too – focusing on the nearest stars to the Earth.
Research is showing us that 10 to 15% of stars have a planet in the habitable zone -where liquid water could exist on the surface.
Because our equipment is not that sensitive it’s best for us to look at stars that are closest to Earth.
One of my proposed studies plans on focusing on just that – the 100 nearest stars to the Earth.

What are the biggest advances since the start of SETI that allow us to focus these searches?
Technologically we have gotten larger and larger telescopes and faster and faster computers. And for radio SETI, the sensitivity of our experiments and the amount of radio channels we can explore is directly related to how fast our computers are. Because we don’t know where ET might be broadcasting it’s a good idea to look at as many channels as possible.  The first experiments decades ago could look at only 10 channels, and now we can look at billions.
Looking into the future, in perhaps a decade time, we might be able to explore the entire radio spectrum over the entire sky.
So what this means to me is that, if, after a couple of more decades of searching we haven’t discovered a signal, we may have to fundamentally rethink the way we conduct the search for ET.

 What do you think are the chances of finding an ET signal?
Overall the SETI community is optimistic since we continue to learn more about astrobiology, and that conditions suitable for life may be quite ubiquitous and technology is getter faster and more sensitive.
But the bottom line is that we really don’t know since we are constantly restricted by the fact that we only have a single example of life anywhere in the universe.  That severely limits the amount of statistics we can apply.
If we could find just one more genesis of life- even if it was just a lonely microbe – I could answer this question much more scientifically and quantitatively.

Why do you think we haven’t stumbled across a signal yet?
The famous Fermi Paradox asks just that: if intelligent life is so common then where are they? My personal opinion is that electrical engineers in the cosmos are pretty rare.
I think life is pretty common and even intelligent life might be relatively common but technological civilizations like our own may be relatively rare.
If every star had a planet with intelligent life just like our own, were long lasting and survive their technological development, and was altruistic and decided to signal its presence, we would have already detected something.
So clearly intelligent life is not that common.  But we need to explore much more of the radio spectrum to really say something more profound about how rare civilizations like our own might be.

What is the most likely form of a signal we might find a signal?
It might very well happen while an astronomer is conducting a new kind of experiment, maybe something that looks at dark energy or dark matter, something that is very sensitive and they encounter something in their observational data they did not expect.
Perhaps after exhausting all possibilities they may come to the most amazing conclusion about where that anomalous feature in their data is coming from.

What would be our response to a true detection?
Any potential signal will need to be confirmed if it is extraterrestrial in origin. After conducting internal tests to confirm that it is indeed real, we would ask other observatories to check out the candidate signal to look for confirmation.
The world would find out pretty quickly too if this happens- mostly likely through twitter.
We are committed to openness and nobody wants to keep secrets. It would also be impossible for anyone to block our ability for us to see extraterrestrial signals.
So if the signals are out there – we will find them. There is nothing between the researchers and the sky. Rest assured there is no ‘secret black box’ installed on our telescopes that filters out our data – we see everything.

What are your personal thoughts about Roswell and other UFO reports?
I personally think it’s largely a psychological phenomena influenced by the media and technological development, and by the fact that we are a very young space-aware society.
I  have never seen any evidence that would lead me to believe that Earth has ever been visited by any extraterrestrial intelligence.
Astronomers are constantly looking at the sky at all wavelengths, with giant telescopes that are sensitive to little blips of light from across the universe, as well as powerful radars that scan the skies around the Earth- and there is no evidence of anything happening.
Being in science, in fact I think it would be nearly impossible to keep any secret like this.
At the end of the day we require evidence – and in the absence of that-  we can’t just conjecture some fantastic happening that is unsupported.

Astronomers Have Been Predicting New Planets in our Solar System for Centuries

 

The theoretical planet Tyche's theoretical orbit. via

For every planet in our solar system there’s a hypothetical planet, some heavenly body that would explain some observed astronomical occurrence. It’s a compelling idea–that our Solar System is filled with unseen masses–which is probably why stories of new planets keep popping up. This week, the planet Tyche (pronounced ty-kee) has reappeared in social media circles. The supposed planet is theorized to be four times the mass of Jupiter and lurk in the outer Oort Cloud, orbiting 375 times farther from the Sun than Pluto. But so far, theories are all we have on this planet. 

Astronomers have been predicting new planets based on mathematical models and observations almost as long as the telescope has been around. It’s how astronomers found Neptune–a body was predicted to orbit outside Uranus to explain its orbit. But some predictions haven’t produced as striking (or concrete) a result as Neptune. 

Tyche isn’t a new hypothetical body. In the 1980s, astronomers theorized that the Sun had a companion. The idea was that if our star was part of a binary system with the unseen companion following a highly elliptical orbit, the sister star would periodically perturb comets in the Oort Cloud and send a shower of comets towards the inner solar system. Some of these icy rocks would slam into the Earth eradicating almost all life. This would explain Earth’s periodic mass extinctions. The Oort-lurking star was appropriately named Nemesis.

But the more scientists study the Earth the more certain we are that mass extinctions don’t happen at regular intervals. The idea of Nemesis was retired, but the potential mass remained. It was renamed Tyche, Nemesis’ benevolent sister, and is thought by some to be a rogue gas giant that was captured by our Solar System. In any case, it's existence is still up for debate.

Neptune, the original "Planet X." via

Similar to the idea of a stellar companion to the Sun is the idea of a companion Earth. A body orbiting exactly opposite our own such that it is always blocked from the Earth by the Sun. The companion Earth theory went out the window as we started exploring the inner solar system and failed to find the predicted body. There's also Nibiru, the theoretical planet on a collision course with the Earth that has yet to be found.

Another long-standing hypothetical planet is Vulcan, a planet once thought to reside inside Mercury’s orbit. An amateur astronomer named Lescarbault reported seeing a round black spot transiting the Sun on March 26, 1859. He thought it was a planet, one too small to explain the observed deviations in Mercury’s orbit but a planet nonetheless. Astronomers tried to find Vulcan during solar eclipses (one in 1869 and one in 1878) but never found solid evidence. Still, reports persisted of astronomers finding disks crossing the Sun, and many believed they were small planets. No spacecraft has ever confirmed these bodies, and it’s thought, in hindsight, that the observed disks were actually comets.

There’s also Planet X. Just like Neptune’s orbit was predicted to explain the irregular orbit of Uranus, Planet X was the theoretical trans-Neptunian planet predicted in 1841 to explain the irregular orbit of Neptune. While Planet X was never confirmed, certain trans-Neptunian bodies do explain the planet’s orbital oddities. Specifically two groups of small bodies that orbit in resonance with the ice giant: one composed of Pluto, 1993 SC, 1993 SB, and 1993 RO, and the second composed of1992 QB1 and 1993 FW. Astronomers called of the search for a trans-Neptunian Planet X in 1992. 

Our current Solar System. via

Along with the theorized planets there have been a host of theoretical moons: Venus’ moon Neith; a moon for Mercury; and additional moons of Jupiter, Saturn, Mars, and Uranus. While no new moons for the terrestrial planets have been confirmed, the few interplanetary missions we’ve launched have confirmed the existence of many new moons for the gas giants. 

So new planets and moons have a history of popping up, and in very few cases have they been confirmed as real bodies. So it’s probably not worth forgetting the order of the planets just yet.

 

Every Time We Look at Neptune, We Find More Moons

A composite showing Neptune, its fuzzy rings, and some moons. via

Though we’ve been exploring space for over a half century, there’s still plenty to find in our own backyard. Case in point: last week, Mark Showalter, a keen-eyed researching with the SETI institute, found a previously unseen moon orbiting Neptune in archival data from the Hubble Space Telescope. 

The moon, for the time being, is called S/2004 N 1. Preliminary estimates suggest it’s no more than 12 miles across, so small that from our Earthly vantage point i’s about 100 times as dim as the faintest star we can see. Even Voyager 2—the planet-hopping probe that flew past Neptune in 1989 and caught a brief glimpse of the planet’s moons and rings—didn’t see this moon. It is currently the smallest known moon in the Neptunian system and the 14th one we’ve found. It also moves fast; it orbits around Neptune once every 23 hours.  

Showalter noticed the moon as a tiny white dot about 65,500 miles away from Neptune. He tracked that dot, watching it move against the starry background through 150 Hubble pictures of Neptune taken between 2004 and 2009. After careful tracking, he was able to plot the moon’s orbit as sitting between the those of Larissa and Proteus.

Neptune‘s largest moon, Triton, was discovered by astronomer William Lassell in 1846, just seventeen days after the discovery of the planet itself. Lassell, like Showalter, noticed the moon as a dot near the planet and tracked its progress along the sky. 

Neptune, as seen by Voyager 2. via

It was over a century before astronomers found another Neptunian satellite. In 1949, Gerard Kuiper, for whom the Kuiper belt of distant small bodies is named, found the second moon Nereid. Nereid, interestingly, isn’t the next largest moon; Proteus is. But it’s too dark and close to its host planet to be seen easily from Earth.
It would take Voyager 2’s close pass by Neptune in 1989 to reveal more moons. Six, in fact: Naiad, Thalassa, Despina, Galetea, Larissa, and Proteus. In 2003, using improved ground-based telescopes, astronomers added five more moons to Neptune’s total:  Halimede, Sao, Psamathe, Laomedeia, and Neso. S/2004 N 1 brings the total to 14. For now.
That we’ve just discovered a previously unknown moon, particularly one as small as S/2004 N 1 raises an interesting question: when is a moon a moon and not just a rock in space?
Until the 17th century, we only knew about one moon: ours. Then Galileo invented the telescope, turned it skyward, found Jupiter’s four largest moons, and opened up a world where any planet could have moons.
Astronomically speaking, a moon is any natural celestial body that orbits around a planet. And for the sake of the “what is a moon” question, a planet includes (in our solar system) the four rocky planets, the four gas giants, the dwarf planets, and a number of minor bodies. So a moon can’t orbit a star—though perhaps the exception would be if some cosmic collision were to knock a moon out of its planetary orbit and into a stellar one.
But that doesn’t mean a moon has to be geologically dead like our Moon. There are a lot of moons some astronomers would happily call planets in light of their surface activity. And there are some moons astronomers think might have been small, independent planets before they were captured by a larger body. Neptune’s Triton, for example.

Triton, in false colour, as seen by Voyager 2 in 1989. via

Voyager 2 returned a wealth of information about Triton, from its cantaloupe rind-like surface to its icy volcanoes that likely spout a mixture of liquid nitrogen, methane, and dust that freezes and falls back onto the surface as snow. The moon is extremely icy, reflecting almost all of the little sunlight that hits it making it one of the coldest objects in the solar system, a frigid -400 degrees Fahrenheit. 

Triton is also the only moon in the solar system that circles its planet in the direction opposite that planet’s rotation. It’s a bizarre arrangement that suggests it might have passed so close to Neptune that it was captured by the planet’s much stronger gravitational pull. And the moon is getting closer to its host planet all the time. Neptune's gravity drags on the counter-orbiting Triton, slowing it down and bringing it closer to itself. It will take millions of years, but eventually Triton will fall close enough to Neptune that it will break apart. 

But in the mean time, there’s a lot to learn about Triton. And Neptune’s other moons. And probably a lot more moons to find. 

 

This composite Hubble Space Telescope picture shows the location of a newly discovered moon, designated S/2004 N1, orbiting the giant planet Neptune, nearly 3 billion miles from Earth.

Initial astrometry indicates that S/2004 N1 travels in a near-circular, uninclined orbit and has a mean radius of about 8-10 km, assuming an albedo of 0.01. This makes S/2004 N1 much smaller than any of Neptune's previously known satellites, and below the detection threshold of the Voyager cameras sent there in 1989. S/2004 N1 is so small and dim that it is roughly 100 million times fainter than the faintest star that can be seen with the naked eye.
S/2004 N1 orbits its parent planet Neptune every 23 hours. The projected radial distance from the parent planet's center is 105,300 +/- 500 km. This places the satellite between the orbits of two other moons of Neptune: Larissa and Proteus.
Discovery:
S/2004 N1 was discovered by Mark Showalter on 1 July 2013 using Hubble Space Telescope (HST) images taken of the Neptune system between 2004 and 2009. Showalter analyzed over 150 archival photographs of the system in which the same white dot appeared over and over again. He then plotted a circular orbit for the moon.
How S/2004 N1 Got its Name:
S/2004 N1 was so designated because it is the first satellite (S) of Neptune (N) to be found from images taken in 2004.

Touring Mars On-line, Real-time, and in 3D for Educators and Students.

James G Jones
Department of Technology and Cognition, College of Education
University of North Texas, Denton, Texas, USA
gjones@unt.edu
Jeramie Hicks
Created Realities Group

Abstract: This paper presents a project started in 2003 that placed over 97% of Mars topography from NASA into an interactive on-line learning environment for use by educators and students connected to the Internet. The possibilities for bringing students into an immersive environment to discuss and participate in math and science are many. This paper will discuss the 3D technology being developed for educational use.

Introduction

The planet Mars has always fascinated us; however, much of that fascination started with misunderstanding and myth. (James, 2003) Mars now represents a future challenge of our nation that the President is proposing in a new space initiative. (Bash, 2004; The Whitehouse, 2004) We have been sending missions to Mars to study the planet since 1964 when the Mariner 4 spacecraft flew by the planet Mars and sent back the first pictures of the Martian surface. (NASA, 2004a) In 1997, the Mars Global Surveyor reached the planet to begin its research. Part of that voyage of discovery included an experiment called the Mars Orbiter Laser Altimeter (MOLA). This experiment collected elevation data (heights) of the surface of Mars. While the research was released during the experiment, not until late 2002 did a normalized data set become available.
When the MOLA normalized data became available (NASA, 2004d), we saw this as a perfect opportunity to show the potential that 3D on-line environments could have in education. The MARS on-line project allows student/teachers/researchers to access information that represents real data collected about the planet Mars. Mars on-line allows a visitor to view in real time across the Internet on as low as a dial-up modem some 1 billion elevation measurements gathered between 1998 and 2001 by NASA (some 2 gigabytes of information). Our technology approach allows us to present small environments like a classroom discussion or scale up to very large environments like Mars within a single methodology. Students can tour and discuss the environments using collaborative tools (audio, text, etc). The real potential in this approach is the ability to provide equal interactions across various Internet user connection speeds. This is an important consideration for students affected by the digital divide.

Mars Global Surveyor

The Mars Global Surveyor (MGS) was launched on November 7, 1996 and research orbit on September 12, 1997. (NASA, 2004b) The Mars Global Surveyor was the first spacecraft to be launched in a decade-long exploration of Mars by NASA. Since the MGS was launched, NASA launches have occurred every 26 months in 1998, 2001, 2003 and 2005, involving orbiters, landers, rovers, and probes to Mars. Figure 1 is a graphic of the spacecraft.

Figure 1 Mars Global Surveyor computer graphic of the spacecraft. (NASA, 2004a)

MOLA ProjectOur project has focused on the data collected by the Mars Orbiter Laser Altimeter (MOLA) project. (NASA, 2004c) The MOLA project collected data until the end of June, 2001, when the instrument failed due to a technical problem (oscillator malfunctioned). Figure 2 shows a photograph of the instrument separated from the spacecraft. The project was designed to map the Martian global topography. The MOLA package works by transmitting a laser pulse from the spacecraft in orbit down towards the surface of the mars. The pulse is then reflected off the Martian surface (or cloud) back to the instrument, where the return is detected. The two-way travel time is recorded, giving a measure of the distance between the spacecraft and the surface. Corrections were then made to the recorded distance based on atmospheric effects and accurate tracking of the spacecraft position allowed an estimate of the surface altitude or cloud height to be adjusted.

Figure 2 MOLA (NASA, 2004c)
The dataset we reference consists of more than 600 million measurements gathered between 1999 and 2001 and was adjusted for consistency. This same dataset has been used by the US Geological Survey to generate new topographic map of mars shown in figure 3. This map can be downloaded from the USGS web site given in the reference section.
Figure 3 - Mars Topographic Map M 25M RKN (U.S. Geological Survey, 2004)

Created Realities Group

The Created Realities Group (CRG) was formed in 2001 with the focus to research and develop 3D online collaborative systems. (CRG, 2002) The goal is to provide a single, low-bandwidth, multi-purpose interface that allows the delivery of distributed education in both asynchronous and synchronous modes. CRG is working towards combining collaborative tools (audio, chat, overheads, white boards, etc), unified communications (e-mail, conferences, etc), and 3D environments such that it increases discourse and engaged learning. The presentation of the NASA Mars global topographic data demonstrates the ability to scale the system from a single classroom to an entire planet. The portal-based 3D presentation system provides for just-in-time display of information. This allows the over 2Gigabytes of MOLA data to be presented just as the user needs it to be displayed, allowing Internet connected users on as low as a dialup connection to access the world information. The elements of collaboration are then woven into the data presentation to allow students to work in the environment to achieve goals and learning. This will be discussed later in the paper.

Mars Online Project

The first step was to take the MOLA dataset and break it into portals, which are the basic building objects of the CRG 3D online system. The MOLA dataset represents some 600 million entries giving longitude, latitude, and elevation in 0.463km increments in long sequential lines of data representing sweeps of the MOLA package as it made orbital passes over the surface of Mars. Each portal is created from 64x64 data points creating a 29.623km square surface by portal (0.463km * 64 = 29.623sqr km). The 600 million entries generates a little over a 2 Gigabyte database of portal and related group information. Table 1 shows the basic information that was generated by this approach.
Table 1: CRG Mars Online Project Specifications (Created Realities Group, 2002) Portals: 253,440 contiguous portals (352 portals NS x 720 portals EW) Portal Size Representations: Single Portal: 29.632 km square Next 9 High-Res: 88.896 km square Next 16 Low-Res: 148.16 km square Maximum Visible Distance: 88.896 km Portal Coverage of Mars: 97.777% Travel Speed: Approx 2700kph Total Visible: 25 portals Database: 12 million group links entries This allows a user to login into the server and visit any location of the planet Mars that is available in the map data. The following figures are screen shots from the client.
Figure 4 - Panorama Shot of Olympus Mons, Top Cone (MARS_19.0_227.0).

Figure 5 - Nicholson crater central peaks (MARS_0.5_195.0).

Conclusion

We are currently working to develop several client widgets that can be used towards the Texas Essential Skills (TEKS) in the areas of 5th grade math and science. The concepts of measuring and scientific investigation can be placed into the Mars environment in order for the students to explore and learn together while completing these essential skills. The potential of taking scientific data and allowing students access to it in a collaborative settings allows new methods of engagement to be employed across many areas of the curriculum.
References:
Bash, D. (2004). Bush to seek manned flights to moon, Mars. Retrieved January 11, 2004, from http://www.cnn.com/2004/TECH/space/01/09/bush.space/index.html Created Realities Group. (2002). CRG Mars On-Line. Retrieved January 5, 2003, from http://created-realities.com/marsonline.html CRG. (2002). Overview of the Created Realities Group VXInteractive Distributed Learning System. Retrieved September 14, 2002, from http://www.created-realities.com James, R. (2003). Mars DOES Have "Canals" With Running Water After All. Retrieved January 13, 2004, from http://www.sciscoop.com/story/2003/3/14/54913/2464 NASA. (2004a). Mars. Retrieved January 13, 2004, from http://nssdc.gsfc.nasa.gov/planetary/planets/marspage.html NASA. (2004b). Mars Global Surveyor. Retrieved January 14, 2004, from http://nssdc.gsfc.nasa.gov/planetary/marsurv.htm NASA. (2004c). Mars Orbiter Laser Altimeter (MOLA). Retrieved January 14, 2004, from http://nssdc.gsfc.nasa.gov/database/MasterCatalog?sc=1996-062A&ex=3 NASA. (2004d). PDS Geosciences Node: Mars Global Surveyor MOLA MEGDRs, from http://pds-geosciences.wustl.edu/missions/mgs/megdr.html The Whitehouse. (2004). President Bush Announces New Vision for Space Exploration Program. Retrieved January 14, 2004, from http://www.whitehouse.gov/news/releases/2004/01/20040114-3.html U.S. Geological Survey. (2004). Maps & Globes Gallery: Mars. Retrieved June 22, 2004, from http://astrogeology.usgs.gov/Gallery/MapsAndGlobes/mars.html#MarsMOLA