Rise of the Super Telescopes: The Large UV Optical Infrared Surveyor (LUVOIR) aka Hubble 2.0

An artist's illustration of a 16 meter segmented mirror space telescope. There are no actual images of LUVOIR because the design hasn't been finalized yet. Image: Northrop Grumman Aerospace Systems & NASA/STScI

We humans have an insatiable hunger to understand the Universe. As Carl Sagan said, “Understanding is Ecstasy.” But to understand the Universe, we need better and better ways to observe it. And that means one thing: big, huge, enormous telescopes.

In this series we’ll look at the world’s upcoming Super Telescopes:

The Giant Magellan Telescope
The Overwhelmingly Large Telescope
The 30 Meter Telescope
The European Extremely Large Telescope
The Large Synoptic Survey Telescope
The James Webb Space Telescope
The Wide Field Infrared Survey Telescope
The Large UV Optical Infrared Surveyor (LUVOIR)

The Large UV Optical Infrared Surveyor Telescope (LUVOIR)

There’s a whole generation of people who grew up with images from the Hubble Space Telescope. Not just in magazines, but on the internet, and on YouTube. But within another generation or two, the Hubble itself will seem quaint, and watershed events of our times, like the Moon Landing, will be just black and white relics of an impossibly distant time. The next generations will be fed a steady diet of images and discoveries stemming from the Super Telescopes. And the LUVOIR will be front and centre among those ‘scopes.

If you haven’t yet heard of LUVOIR, it’s understandable; LUVOIR is in the early stages of being defined and designed. But LUVOIR represents the next generation of space telescopes, and its power will dwarf that of its predecessor, the Hubble.

LUVOIR (its temporary name) will be a space telescope, and it will do its work at the LaGrange 2 point, the same place that JWST will be. L2 is a natural location for space telescopes. At the heart of LUVOIR will be a 15m segmented primary mirror, much larger than the Hubble’s mirror, which is a mere 2.4m in diameter. In fact, LUVOIR will be so large that the Hubble could drive right through the hole in the center of it.

This not-to-scale image of the Solar System shows the LaGrangian points. LUVOIR will be located in a halo orbit at L2, along with the JWST. Image: By Xander89 - File:Lagrange_points2.svg, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=36697081 — This not-to-scale image of the Solar System shows the LaGrangian points. LUVOIR will be located in a halo orbit at L2, along with the JWST. Image: By Xander89 – File:Lagrange_points2.svg, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=36697081

While the James Webb Space Telescope will be in operation much sooner than LUVOIR, and will also do amazing work, it will observe primarily in the infrared. LUVOIR, as its name makes clear, will have a wider range of observation more like Hubble’s. It will see in the Ultra-Violet spectrum, the Optical spectrum, and the Infrared spectrum.

Recently, Brad Peterson spoke with Fraser Cain on a weekly Space Hangout, where he outlined the plans for the LUVOIR. Brad is a recently retired Professor of Astronomy at the Ohio State University, where served as chair of the Astronomy Department for 9 years. He is currently the chair of the Science Committee at NASA’s Advisory Council. Peterson is also a Distinguished Visiting Astronomer at the Space Telescope Science Institute, and the chair of the astronomy section of the American Association for the Advancement of Science.

Different designs for LUVOIR have been discussed, but as Peterson points out in the interview above, the plan seems to have settled on a 15m segmented mirror. A 15m mirror is larger than any optical light telescope we have on Earth, though the Thirty Meter Telescope and others will soon be larger.

“Segmented telescopes are the technology of today when it comes to ground-based telescopes. The JWST has taken that technology into space, and the LUVOIR will take segmented design one step further,” Peterson said. But the segmented design of LUVOIR differs from the JWST in several ways.

“…the LUVOIR will take segmented design one step further.” – Brad Peterson

JWST’s mirrors are made of beryllium and coated with gold. LUVOIR doesn’t require the same exotic design. But it has other requirements that will push the envelope of segmented telescope design. LUVOIR will have a huge array of CCD sensors that will require an enormous amount of electrical power to operate.

The Hubble Space Telescope on the left has a 2.4 meter mirror and the James Webb Space Telescope has a 6.5 meter mirror. LUVOIR, not shown, will dwarf them both with a massive 15 meter mirror. Image: NASA

LUVOIR will not be cryogenically cooled like the JWST is, because it’s not primarily an Infrared observatory. LUVOIR will also be designed to be serviceable. In fact, the US Congress now requires all space telescopes to be serviceable.

“Congress has mandated that all future large space telescopes must be serviceable if practicable.” – Brad Peterson

LUVOIR is designed to have a long life. It’s multiple instruments will be replaceable, and the hope is that it will last in space for 50 years. Whether it will be serviced by robots, or by astronauts, has not been determined. It may even be designed so that it could be brought back from L2 for servicing.

LUVOIR will contribute to the search for life on other worlds. A key requirement for LUVOIR is that it do spectroscopy on the atmospheres of distant planets. If you can do spectroscopy, then you can determine habitability, and, potentially, even if a planet is inhabited. This is the first main technological challenge for LUVOIR. This spectroscopy requires a powerful coronagraph to suppress the light of the stars that exoplanets orbit. LUVOIR’s coronagraph will excel at this, with a ratio of starlight suppression of 10 billion to 1. With this capability, LUVOIR should be able to do spectroscopy on the atmospheres of small, terrestrial exoplanets, rather than just larger gas giants.

“This telescope is going to be remarkable. The key science that it’s going to do be able to do is spectroscopy of planets in the habitable zone around nearby stars.” – Brad Peterson

This video from NASA’s Goddard Space Flight Center talks about the search for life, and how telescopes like LUVOIR will contribute to the search. At the 15:00 mark, Dr. Aki Roberge talks about how spectroscopy is key to finding signs of life on exoplanets, and how LUVOIR will take that search one step further.

Using spectroscopy to search for signs of life on exoplanets is just one of LUVOIR’s science goals.

LUVOIR is tasked with other challenges as well, including:

Mapping the distribution of dark matter in the Universe.
Isolating the source of gravitational waves.
Imaging circumstellar disks to see how planets form.
Identifying the first starlight in the Universe, studying early galaxies and finding the first black holes.
Studying surface features of worlds in our Solar System.

To tackle all these challenges, LUVOIR will have to clear other technological hurdles. One of them is the requirement for long exposure times. This puts enormous constraints on the stability of the scope, since its mirror is so large. A system of active supports for the mirror segments will help with stability. This is a trait it shares with other terrestrial Super Telescopes like the Thirty Meter Telescope and the European Extremely Large Telescope. Each of those had hundreds of segments which have to be controlled precisely with computers.

A circumstellar disk of debris around a matured stellar system may indicate that Earth-like planets lie within. LUVOIR will be able to see inside the disk to watch planets forming. Credit: NASA — A circumstellar disk of debris around a matured stellar system may indicate that Earth-like planets lie within. LUVOIR will be able to see inside the disk to watch planets forming.
Credit: NASA

LUVOIR’s construction, and how it will be placed in orbit are also significant considerations.

According to Peterson, LUVOIR could be launched on either of the heavy lift rockets being developed. The Falcon Heavy is being considered, as is the Space Launch System. The SLS Block 1B could do it, depending on the final size of LUVOIR.

“I’s going to require a heavy lift vehicle.” – Brad Peterson

Or, LUVOIR may never be launched into space. It could be assembled in space with pre-built components that are launched one at a time, just like the International Space Station. There are several advantages to that.

With assembly in space, the telescope doesn’t have to be built to withstand the tremendous force it takes to launch something into orbit. It also allows for testing when completed, before being sent to L2. Once the ‘scope was assembled and tested, a small ion propulsion engine could be used to power it to L2.

It’s possible that the infrastructure to construct LUVOIR in space will exist in a decade or two. NASA’s Deep Space Gateway in cis-lunar space is planned for the mid-20s. It would act as a staging point for deep-space missions, and for missions to the lunar surface.

LUVOIR is still in the early stages. The people behind it are designing it to meet as many of the science goals as they can, all within the technological constraints of our time. Planning has to start somewhere, and the plans presented by Brad Peterson represent the current thinking behind LUVOIR. But there’s still a lot of work to do.

“Typical time scale from selection to launch of a flagship mission is something like 20 years.” – Brad Peterson

As Peterson explains, LUVOIR will have to be chosen as NASA’s highest priority during the 2020 Decadal Survey. Once that occurs, then a couple more years are required to really flesh out the design of the mission. According to Peterson, “Typical time scale from selection to launch of a flagship mission is something like 20 years.” That gets us to a potential launch in the mid-2030s.

Along the way, LUVOIR will be given a more suitable name. James Webb, Hubble, Kepler and others have all had important missions named after them. Perhaps its Carl Sagan’s turn.

“The Carl Sagan Space Telescope” has a nice ring to it, doesn’t it?

May 5, 2017May 5, 2017 by Evan Gough

A Single Wave, Bigger Than the Milky Way, is Rolling Through the Perseus Galaxy Cluster

NASA has discovered a wave of hot gas larger than the Milky Way rolling through the Perseus galaxy cluster. This X-ray image is the result of 16 days of observing with the Chandra X-ray Observatory. The image was filtered to make details easier to see.Credit: NASA's Goddard Space Flight Center/Stephen Walker et al.

An international team of scientists has discovered an enormous wave of hot gas rolling its way through the Perseus galaxy cluster. The wave is a giant version of what’s called a Kelvin-Helmholtz wave. They’re created when two fluids intersect at different velocities: for example, when wind blows over water.

In this instance, the wave was caused by a small galaxy cluster grazing the Perseus cluster, and setting off a chain of events lasting billions of years. The findings appear in a paper in the June 2017 issue of the journal Monthly Notices of the Royal Astronomical Society.

“The wave we’ve identified is associated with the flyby of a smaller cluster, which shows that the merger activity that produced these giant structures is still ongoing.” – Stephen Walker, NASA’s Goddard Space Flight Center.

“Perseus is one of the most massive nearby clusters and the brightest one in X-rays, so Chandra data provide us with unparalleled detail,” said lead scientist Stephen Walker at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “The wave we’ve identified is associated with the flyby of a smaller cluster, which shows that the merger activity that produced these giant structures is still ongoing.”

The Perseus galaxy cluster, also known as Abell 426, is 240 million light years away, and is about 11 million light years across. It’s one of the most massive objects we know of, and it’s named after the Perseus constellation, which appears in the same part of the sky.

Galaxy clusters are the largest gravitationally-bound objects in the Universe. Most of the observable matter in galaxy clusters is gas. But the gas is super hot—tens of millions of degrees hot—which means it emits x-rays.

X-Ray observations of Perseus have revealed several features and structures in the gas structure of the cluster. Some of them are bubble-like features caused by the super-massive black hole (SMBH) in NGC 1275, the Perseus cluster’s central galaxy. Another of these features is known as “the bay.” The bay is a concave feature which couldn’t have been formed by the SMBH.

This Hubble image shows NGC 1275, the Super-Massive Black Hole at the center of the Perseus cluster. NGC 1275 could not have been responsible for the "bay" feature found in Perseus. Image: By NASA, ESA, and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration - http://hubblesite.org/newscenter/archive/releases/2008/28/image/a/, Public Domain, https://commons.wikimedia.org/w/index.php?curid=4634173 — This Hubble image shows NGC 1275, the Super-Massive Black Hole at the center of the Perseus cluster. NGC 1275 could not have been responsible for the “bay” feature found in Perseus. Image: By NASA, ESA, and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration – http://hubblesite.org/newscenter/archive/releases/2008/28/image/a/, Public Domain, https://commons.wikimedia.org/w/index.php?curid=4634173

The bay is a puzzle because it doesn’t produce any emissions, which would be expected of something formed by a SMBH. The bay also doesn’t conform to models of how gas should behave in this situation.

The lead scientist behind the study is Stephen Walker at NASA’s Goddard Space Flight Center. Walker turned to the Chandra X-ray Observatory to help solve this puzzle. Existing Chandra images of the Perseus cluster were filtered in order to highlight the edges of structures, and to make any subtle details more visible.

These filtered and processed images were then compared to computer simulations of galaxy clusters merging. John ZuHone, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics, has created an online catalog of these simulations.

“Galaxy cluster mergers represent the latest stage of structure formation in the cosmos.” -John ZuHone, Harvard-Smithsonian Center for Astrophysics.

“Galaxy cluster mergers represent the latest stage of structure formation in the cosmos. Hydrodynamic simulations of merging clusters allow us to produce features in the hot gas and tune physical parameters, such as the magnetic field. Then we can attempt to match the detailed characteristics of the structures we observe in X-rays.” -John ZuHone, Harvard-Smithsonian Center for Astrophysics.

This alternate image of the Perseus galaxy cluster shows the wave at the 7 o'clock position. Image: NASA's Goddard Space Flight Center/Stephen Walker et al. — This alternate image of the Perseus galaxy cluster shows the wave at the 7 o’clock position. Image: NASA’s Goddard Space Flight Center/Stephen Walker et al.

One of the simulations matched what astronomers were seeing in Perseus. In it, a large cluster like Perseus had settled itself into two regions: a colder region of gas around 30 million degrees Celsius, and a hotter region of gas at almost 100 million degrees Celsius. In this model, a cluster smaller than Perseus, but about a thousand times more massive than the Milky Way passes close to Perseus, missing its center by about 650,000 light years.

That happened about 2.5 billion years ago, and it set off a chain of events still playing itself out.

The near miss caused a gravitational disturbance that created an expanding spiral of the colder gas. An enormous wave of gas has formed at the edge of the spiral of colder gas, where it intersects with the hotter gas. This is the Kelvin-Helmholtz wave seen in the images.

“We think the bay feature we see in Perseus is part of a Kelvin-Helmholtz wave, perhaps the largest one yet identified, that formed in much the same way as the simulation shows,” Walker said. “We have also identified similar features in two other galaxy clusters, Centaurus and Abell 1795.”

The study provided another benefit besides just spotting an impossibly enormous wave. It allowed the team to measure the magnetic properties of the Perseus cluster. The researchers discovered that the strength of the magnetic field in the cluster affected the size of the wave of gas. It the field is too strong, the waves don’t form at all, and if the magnetic field is too weak, then the waves would be even larger.

According to the team, there is no other known way to measure the magnetic field.

Source: Scientists Find Giant Wave Rolling Through the Perseus Galaxy Cluster

May 4, 2017May 4, 2017 by Evan Gough

Enjoy The Biggest Infrared Image Ever Taken Of The Small Magellanic Cloud Without All That Pesky Dust In The Way

The Small Magellanic Cloud is one of the highlights of the southern sky. It can be seen with the naked eye. But it is obscured by clouds of interstellar gas and dust, which makes it hard for optical telescopes to get a good look at it. This image, taken with the ESO's VISTA. is the biggest-ever image of the SMC, and shows millions of stars. Credit: ESO/VISTA VMC

The Small Magellanic Cloud (SMC) galaxy. Credit: ESA/VISTA

The Small Magellanic Cloud (SMC) is one of the Milky Way’s nearest companions (along with the Large Magellanic Cloud.) It’s visible with the naked eye in the southern hemisphere. A new image from the European Southern Observatory’s (ESO) Visible and Infrared Survey Telescope for Astronomy (VISTA) has peered through the clouds that obscure it and given us our biggest image ever of the dwarf galaxy.

The SMC contains several hundred million stars, is about 7,000 light years in diameter, and is about 200,000 light years away. It’s one of the most distant objects that we can see with the naked eye, and can only be seen from the southern hemisphere (and the lowest latitudes of the northern hemisphere.)

The Small Magellanic Cloud is located in the Tucana constellation (The Toucan) in the southern hemisphere. The SMC is shown in green outline around the word 'Tucana'. Also shown are NGC 104 and NGC 362, unrelated objects that are much closer to Earth. Image: ESO, IAU and Sky & Telescope — The Small Magellanic Cloud is located in the Tucana constellation (The Toucan) in the southern hemisphere. The SMC is shown in green outline around the word ‘Tucana’. Also shown are NGC 104 and NGC 362, unrelated objects that are much closer to Earth. Image: ESO, IAU and Sky & Telescope

The SMC is a great target for studying how stars form because it’s so close to Earth, relatively speaking. But the problem is, its detail is obscured by clouds of interstellar gas and dust. So an optical survey of the Cloud is difficult.

But the ESO’s VISTA instrument is ideal for the task. VISTA is a near-infrared telescope, and infrared light is not blocked by the dust. VISTA was built at the ESO’s Paranal Observatory, in the Atacama Desert in Chile where it enjoys fantastic observing conditions. VISTA was designed to perform several surveys, including the Vista Magellanic Survey.

Explore the Zoomable image of the Small Magellanic Cloud. (You won’t be disappointed.)

The VISTA Magellanic Survey is focused on 3 main objectives:

The study of stellar populations in the Magellanic Clouds
The history of star formation in the Magellanic Clouds
The three-dimensional structure of the Magellanic Clouds

An international team led by Stefano Rubele of the University of Padova has studied this image, and their work has produced some surprising results. VISTA has shown us that most of the stars in this image are much younger than stars in other neighbouring galaxies. It’s also shown us that the SMC’s morphology is that of a warped disc. These are only early results, and there’s much more work to be done analyzing the VISTA image.

VISTA inside its enclosure at Paranal. VISTA has a 4.1 meter mirror, and its job is to survey large sections of the sky at once. In the background is the ESO's Very Large Telescope. Image: G. Hüdepohl — VISTA inside its enclosure at Paranal. VISTA has a 4.1 meter mirror, and its job is to survey large sections of the sky at once. In the background is the ESO’s Very Large Telescope. Image: G. Hüdepohl (atacamaphoto.com)/ESO

The team presented their research in a paper titled “The VMC survey – XIV. First results on the look-back time star formation rate tomography of the Small Magellanic Cloud“, published in the journal Monthly Notices of the Royal Astronomical Society.

As the authors say in their paper, the SMC is a great target for study because of its “rich population of star clusters, associations, stellar pulsators, primary distance indicators, and stars in shortlived evolutionary stages.” In a way, we’re fortunate to have the SMC so close. But studying the SMC was difficult, until the VISTA came online with its infrared capabilities.

VISTA saw first light on December 11th, 2009. It’s time is devoted to systematic surveys of the sky. In its first five years, it has undertaken large surveys of the entire southern sky, and also studied small patches of the sky to discern extremely faint objects. The leading image in this article is from the Vista Magellanic Survey, a survey covering 184 square degrees of the sky, taking in both the Small Magellanic Cloud and the Large Magellanic Cloud, and their environment.

Source: VISTA Peeks Through the Small Magellanic Cloud’s Dusty Veil

May 2, 2017May 2, 2017 by Evan Gough

Rise Of The Super Telescopes: The Wide Field Infrared Survey Telescope

NASA's Wide Field Infrared Survey Telescope (WFIRST) will capture Hubble-quality images covering swaths of sky 100 times larger than Hubble does, enabling cosmic evolution studies. Its Coronagraph Instrument will directly image exoplanets and study their atmospheres. Credits: NASA/GSFC/Conceptual Image Lab — NASA's Wide Field Infrared Survey Telescope (WFIRST) will capture Hubble-quality images covering swaths of sky 100 times larger than Hubble does. These enormous images will allow astronomers to study the evolution of the cosmos. Its Coronagraph Instrument will directly image exoplanets and study their atmospheres. Credits: NASA/GSFC/Conceptual Image Lab

In this series we’ll look at the world’s upcoming Super Telescopes:

The Giant Magellan Telescope
The Overwhelmingly Large Telescope
The 30 Meter Telescope
The European Extremely Large Telescope
The Large Synoptic Survey Telescope
The James Webb Space Telescope
The Wide Field Infrared Survey Telescope

The Wide Field Infrared Survey Telescope (WFIRST)

It’s easy to forget the impact that the Hubble Space Telescope has had on our state of knowledge about the Universe. In fact, that might be the best measurement of its success: We take the Hubble, and all we’ve learned from it, for granted now. But other space telescopes are being developed, including the WFIRST, which will be much more powerful than the Hubble. How far will these telescopes extend our understanding of the Universe?

“WFIRST has the potential to open our eyes to the wonders of the universe, much the same way Hubble has.” – John Grunsfeld, NASA Science Mission Directorate

The WFIRST might be the true successor to the Hubble, even though the James Webb Space Telescope (JWST) is often touted as such. But it may be incorrect to even call WFIRST a telescope; it’s more accurate to call it an astrophysics observatory. That’s because one of its primary science objectives is to study Dark Energy, that rather mysterious force that drives the expansion of the Universe, and Dark Matter, the difficult-to-detect matter that slows that expansion.

WFIRST will have a 2.4 meter mirror, the same size as the Hubble. But, it will have a camera that will expand the power of that mirror. The Wide Field Instrument is a 288-megapixel multi-band near-infrared camera. Once it’s in operation, it will capture images that are every bit as sharp as those from Hubble. But there is one huge difference: The Wide Field Instrument will capture images that cover over 100 times the sky that Hubble does.

Alongside the Wide Field Instrument, WFIRST will have the Coronagraphic Instrument. The Coronagraphic Instrument will advance the study of exoplanets. It’ll use a system of filters and masks to block out the light from other stars, and hone in on planets orbiting those stars. This will allow very detailed study of the atmospheres of exoplanets, one of the main ways of determining habitability.

WFIRST is slated to be launched in 2025, although it’s too soon to have an exact date. But when it launches, the plan is for WFIRST to travel to the Sun-Earth LaGrange Point 2 (L2.) L2 is a gravitationally balanced point in space where WFIRST can do its work without interruption. The mission is set to last about 6 years.

Probing Dark Energy

“WFIRST has the potential to open our eyes to the wonders of the universe, much the same way Hubble has,” said John Grunsfeld, astronaut and associate administrator of NASA’s Science Mission Directorate at Headquarters in Washington. “This mission uniquely combines the ability to discover and characterize planets beyond our own solar system with the sensitivity and optics to look wide and deep into the universe in a quest to unravel the mysteries of dark energy and dark matter.”

In a nutshell, there are two proposals for what Dark Energy can be. The first is the cosmological constant, where Dark Energy is uniform throughout the cosmos. The second is what’s known as scalar fields, where the density of Dark Energy can vary in time and space.

We used to think that the Universe expanded at a steady rate. Then in the 1990s we discovered that the expansion had started accelerating about 5 billion years ago. Dark Energy is the name given to the force driving that expansion. Image: NASA/STSci/Ann Feild — We used to think that the Universe expanded at a steady rate. Then in the 1990s we discovered that the expansion had accelerated. Dark Energy is the name given to the force driving that expansion. Image: NASA/STSci/Ann Feild

Since the 1990s, observations have shown us that the expansion of the Universe is accelerating. That acceleration started about 5 billion years ago. We think that Dark Energy is responsible for that accelerated expansion. By providing such large, detailed images of the cosmos, WFIRST will let astronomers map expansion over time and over large areas. WFIRST will also precisely measure the shapes, positions and distances of millions of galaxies to track the distribution and growth of cosmic structures, including galaxy clusters and the Dark Matter accompanying them. The hope is that this will give us a next level of understanding when it comes to Dark Energy.

If that all sounds too complicated, look at it this way: We know the Universe is expanding, and we know that the expansion is accelerating. We want to know why it’s expanding, and how. We’ve given the name ‘Dark Energy’ to the force that’s driving that expansion, and now we want to know more about it.

Probing Exoplanets

Dark Energy and the expansion of the Universe is a huge mystery, and a question that drives cosmologists. (They really want to know how the Universe will end!) But for many of the rest of us, another question is even more compelling: Are we alone in the Universe?

There’ll be no quick answer to that one, but any answer we find begins with studying exoplanets, and that’s something that WFIRST will also excel at.

Artist's concept of the TRAPPIST-1 star system, an ultra-cool dwarf that has seven Earth-size planets orbiting it. We're going to keep finding more and more solar systemsl like this, but we need observatories like WFIRST, with starshades, to understand the planets better. Credits: NASA/JPL-Caltech — Artist’s concept of the TRAPPIST-1 star system, an ultra-cool dwarf that has seven Earth-size planets orbiting it. We’re going to keep finding more and more solar systems like this, but we need observatories like WFIRST to understand the planets better. Credits: NASA/JPL-Caltech

“WFIRST is designed to address science areas identified as top priorities by the astronomical community,” said Paul Hertz, director of NASA’s Astrophysics Division in Washington. “The Wide-Field Instrument will give the telescope the ability to capture a single image with the depth and quality of Hubble, but covering 100 times the area. The coronagraph will provide revolutionary science, capturing the faint, but direct images of distant gaseous worlds and super-Earths.”

“The coronagraph will provide revolutionary science, capturing the faint, but direct images of distant gaseous worlds and super-Earths.” – Paul Hertz, NASA Astrophysics Division

The difficulty in studying exoplanets is that they are all orbiting stars. Stars are so bright they make it impossible to see their planets in any detail. It’s like staring into a lighthouse miles away and trying to study an insect near the lighthouse.

The Coronagraphic Instrument on board WFIRST will excel at blocking out the light of distant stars. It does that with a system of mirrors and masks. This is what makes studying exoplanets possible. Only when the light from the star is dealt with, can the properties of exoplanets be examined.

This will allow detailed measurements of the chemical composition of an exoplanet’s atmosphere. By doing this over thousands of planets, we can begin to understand the formation of planets around different types of stars. There are some limitations to the Coronagraphic Instrument, though.

The Coronagraphic Instrument was kind of a late addition to WFIRST. Some of the other instrumentation on WFIRST isn’t optimized to work with it, so there are some restrictions to its operation. It will only be able to study gas giants, and so-called Super-Earths. These larger planets don’t require as much finesse to study, simply because of their size. Earth-like worlds will likely be beyond the power of the Coronagraphic Instrument.

These limitations are no big deal in the long run. The Coronagraph is actually more of a technology demonstration, and it doesn’t represent the end-game for exoplanet study. Whatever is learned from this instrument will help us in the future. There will be an eventual successor to WFIRST some day, perhaps decades from now, and by that time Coronagraph technology will have advanced a great deal. At that future time, direct snapshots of Earth-like exoplanets may well be possible.

But maybe we won’t have to wait that long.

Starshade To The Rescue?

There is a plan to boost the effectiveness of the Coronagraph on WFIRST that would allow it to image Earth-like planets. It’s called the EXO-S Starshade.

The EXO-S Starshade is a 34m diameter deployable shading system that will block starlight from impairing the function of WFIRST. It would actually be a separate craft, launched separately and sent on its way to rendezvous with WFIRST at L2. It would not be tethered, but would orient itself with WFIRST through a system of cameras and guide lights. In fact, part of the power of the Starshade is that it would be about 40,000 to 50,000 km away from WFIRST.

Dark Energy and Exoplanets are priorities for WFIRST, but there are always other discoveries awaiting better telescopes. It’s not possible to predict everything that we’ll learn from WFIRST. With images as detailed as Hubble’s, but 100 times larger, we’re in for some surprises.

“This mission will survey the universe to find the most interesting objects out there.” – Neil Gehrels, WFIRST Project Scientist

“In addition to its exciting capabilities for dark energy and exoplanets, WFIRST will provide a treasure trove of exquisite data for all astronomers,” said Neil Gehrels, WFIRST project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “This mission will survey the universe to find the most interesting objects out there.”

With all of the Super Telescopes coming on line in the next few years, we can expect some amazing discoveries. In 10 to 20 years time, our knowledge will have advanced considerably. What will we learn about Dark Matter and Dark Energy? What will we know about exoplanet populations?

Right now it seems like we’re just groping towards a better understanding of these things, but with WFIRST and the other Super Telescopes, we’re poised for more purposeful study.

April 25, 2017April 28, 2017 by Evan Gough

Designing The Hanging Gardens Of Mars

The prototype greenhouse is being designed to provide astronauts with a continuous vegetarian diet. Image: University of Arizona.

NASA is all about solving challenges, and the goal of having a prolonged presence in space, or a colony on Mars or some other world, is full of challenges, including the necessity of growing food. Scientists at Kennedy Advanced Life Support Research are working on the Prototype Lunar/Mars Greenhouse Project to try and meet that challenge.

The Prototype Lunar/Mars Greenhouse Project (PLMGP) is all about growing vegetables for astronauts during extended stays on the Moon, on Mars, or anywhere they can’t be resupplied from Earth. Beyond growing food, the Project aims to understand how food-growing systems can also be a part of life-support systems.

“The approach uses plants to scrub carbon dioxide, while providing food and oxygen.” – Dr. Ray Wheeler

“We’re working with a team of scientists, engineers and small businesses at the University of Arizona to develop a closed-loop system. The approach uses plants to scrub carbon dioxide, while providing food and oxygen,” said Dr. Ray Wheeler, lead scientist in Kennedy Advanced Life Support Research.

The prototype itself is an inflatable, deployable system that researchers call a bioregenerative life support system. As crops are grown, the system recycles, water, recycles waste, and revitalizes the air.

The system is hydroponic, so no soil is needed. Water that is either brought along on missions or gathered in situ—on the Moon or at Mars for example—is enriched with nutrient salts, and flows continuously through plant root systems. Air in the system is recycled too. Astronauts exhale carbon dioxide, which plants absorb. Through photosynthesis, the plants produce oxygen for the astronauts.

This 18 foot long tube is a prototype of a bioregenerative life support system. The system grows crops, but also regenerates water and air. It's at the University of Arizona's Controlled Environment Agriculture Center. Image: University of Arizona — This 18 foot long tube is a prototype of a bioregenerative life support system. The system grows crops, but also regenerates water and air. It’s at the University of Arizona’s Controlled Environment Agriculture Center. Image: University of Arizona

“We’re mimicking what the plants would have if they were on Earth and make use of these processes for life support,” said Dr. Gene Giacomelli, director of the Controlled Environment Agriculture Center at the University of Arizona. “The entire system of the lunar greenhouse does represent, in a small way, the biological systems that are here on Earth.”

“The entire system of the lunar greenhouse does represent, in a small way, the biological systems that are here on Earth.” – Dr. Gene Giacomelli

A key part of a system like this is knowing what astronauts will have to bring with them, and what resources they can find at their destination. This includes which type of plants and seeds will be needed, as well as how much water might be available once astronauts reach their destination. Methods of extracting water on Mars or the Moon are also being researched and developed.

Even if the necessary water can be found in situ on Mars and the Moon, that hardly means those are easy places to grow food. Astronauts have to be protected from radiation, and so will crops. These greenhouse chambers would have to buried underground, which means specialized lighting systems are also required.

“We’ve been successful in using electric LED (light emitting diode) lighting to grow plants,” Dr. Wheeler said. “We also have tested hybrids using both natural and artificial lighting.” Solar light could be captured with light concentrators that track the sun and then convey the light to the chamber using fiber optic bundles.

These systems are not NASA’s first experience at growing crops in space. Experiments aboard the International Space Station (ISS) have been an important part of the research into crop production in non-terrestrial environments. The Veggie Plant Growth System was NASA’s first attempt, and astronauts successfully harvested lettuce from that system.

NASA astronaut Shane Kimbrough harvesting lettuce from 'VEGGIE' on the International Space Station. Image: NASA — NASA astronaut Shane Kimbrough harvesting lettuce from ‘VEGGIE’ on the International Space Station. Image: NASA

Earth has well-established systems for sustaining life, and this project is all about taking some of that to distant destinations in space.

“I think it’s interesting to consider that we’re taking our terrestrial companions with us,” Wheeler said. “While there may be ways to engineer around it in terms of stowage and resupply, it wouldn’t be as sustainable. The greenhouses provide a more autonomous approach to long-term exploration on the moon, Mars and beyond.”

April 25, 2017April 28, 2017 by Evan Gough

Another Strange Discovery From LHC That Nobody Understands

New results from ALICE at the Large Hadron Collider show so-called strange hadrons being created where none were expected. As the number of proton-proton collisions (the blue lines) increase, the more of these strange hadrons are seen (as shown by the red squares in the graph). (Image: CERN)

There are some strange results being announced in the physics world lately. A fluid with a negative effective mass, and the discovery of five new particles, are all challenging our understanding of the universe.

New results from ALICE (A Large Ion Collider Experiment) are adding to the strangeness.

ALICE is a detector on the Large Hadron Collider (LHC). It’s one of seven detectors, and ALICE’s role is to “study the physics of strongly interacting matter at extreme energy densities, where a phase of matter called quark-gluon plasma forms,” according to the CERN website. Quark-gluon plasma is a state of matter that existed only a few millionths of a second after the Big Bang.

In what we might call normal matter—that is the familiar atoms that we all learn about in high school—protons and neutrons are made up of quarks. Those quarks are held together by other particles called gluons. (“Glue-ons,” get it?) In a state known as confinement, these quarks and gluons are permanently bound together. In fact, quarks have never been observed in isolation.

A cut-away view of the ALICE detector at CERN’s LHC. Image: By Pcharito – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=31365856

The LHC is used to collide particles together at extremely high speeds, creating temperatures that can be 100,000 times hotter than the center of our Sun. In new results just released from CERN, lead ions were collided, and the resulting extreme conditions come close to replicating the state of the Universe those few millionths of a second after the Big Bang.

In those extreme temperatures, the state of confinement was broken, and the quarks and gluons were released, and formed quark-gluon plasma.

So far, this is pretty well understood. But in these new results, something additional happened. There was increased production of what are called “strange hadrons.” Strange hadrons themselves are well-known particles. They have names like Kaon, Lambda, Xi and Omega. They’re called strange hadrons because they each have one “strange quark.”

If all of this seems a little murky, here’s the dinger: Strange hadrons may be well-known particles, because they’ve been observed in collisions between heavy nuclei. But they haven’t been observed in collisions between protons.

“Being able to isolate the quark-gluon-plasma-like phenomena in a smaller and simpler system…opens up an entirely new dimension for the study of the properties of the fundamental state that our universe emerged from.” – Federico Antinori, Spokesperson of the ALICE collaboration.

“We are very excited about this discovery,” said Federico Antinori, Spokesperson of the ALICE collaboration. “We are again learning a lot about this primordial state of matter. Being able to isolate the quark-gluon-plasma-like phenomena in a smaller and simpler system, such as the collision between two protons, opens up an entirely new dimension for the study of the properties of the fundamental state that our universe emerged from.”

Enhanced Strangeness?

The creation of quark-gluon plasma at CERN provides physicists an opportunity to study the strong interaction. The strong interaction is also known as the strong force, one of the four fundamental forces in the Universe, and the one that binds quarks into protons and neutrons. It’s also an opportunity to study something else: the increased production of strange hadrons.

In a delicious turn of phrase, CERN calls this phenomenon “enhanced strangeness production.” (Somebody at CERN has a flair for language.)

Enhanced strangeness production from quark-gluon plasma was predicted in the 1980s, and was observed in the 1990s at CERN’s Super Proton Synchrotron. The ALICE experiment at the LHC is giving physicists their best opportunity yet to study how proton-proton collisions can have enhanced strangeness production in the same way that heavy ion collisions can.

According to the press release announcing these results, “Studying these processes more precisely will be key to better understand the microscopic mechanisms of the quark-gluon plasma and the collective behaviour of particles in small systems.”

I couldn’t have said it better myself.

April 24, 2017April 28, 2017 by Evan Gough

Into The Submillimeter: The Early Universe’s Formation

A new study looked at 52 submillimeter galaxies to help us understand the early ages of our Universe. Image: University of Nottingham/Omar Almaini

In order to make sense of our Universe, astronomers have to work hard, and they have to push observing technology to the limit. Some of that hard work revolves around what are called sub-millimeter galaxies (SMGs.) SMGs are galaxies that can only be observed in the submillimeter range of the electromagnetic spectrum.

The sub-millimeter range is the waveband between the far-infrared and microwave wavebands. (It’s also called Terahertz radiation.) We’ve only had the capability to observe in the sub-millimeter range for a couple decades. We’ve also increased the angular resolution of telescopes, which helps us discern separate objects.

The submillimter wavelength is also called Terahertz Radiation, and is between Infrared and Microwave Radiation on the spectrum. Image: By Tatoute, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=6884073

SMGs themselves are dim in other wavelengths, because they’re obscured by dust. The optical light is blocked by the dust, and absorbed and re-emitted in the sub-millimeter range. In the sub-millimeter, SMGs are highly luminous; trillions of times more luminous than the Sun, in fact.

This is because they are extremely active star-forming regions. SMGs are forming stars at a rate hundreds of times greater than the Milky Way. They are also generally older, more distant galaxies, so they’re red-shifted. Studying them helps us understand galaxy and star formation in the early universe.

ALMA is an array of dishes located at the Atacama Desert in Chile. Image: ALMA (ESO/NAOJ/NRAO), O. Dessibourg

A new study, led by James Simpson of the University of Edinburgh and Durham University, has examined 52 of these galaxies. In the past, it was difficult to know the exact location of SMGs. In this study, the team relied on the power of the Atacama Large Millimeter/submillimeter array (ALMA) to get a much more precise measurement of their location. These 52 galaxies were first identified by the Submillimeter Common-User Bolometer Array (SCUBA-2) in the UKIDSS Ultra Deep Survey.

There are four major results of the study:

48 of the SMGs are non-lensed, meaning that there is no object of sufficient mass between us and them to distort their light. Of these, the team was able to constrain the red-shift (z) for 35 of them to a median range of z-2.65. When it comes to extra-galactic observations like this, the higher the red-shift, the further away the object is. (For comparison, the highest red-shift object we know of is a galaxy called GN-z11, at z=11.1, which corresponds to about 400 million years after the Big Bang.
Another type of galaxy, the Ultra-Luminous Infrared Galaxy (ULIRG) were thought to be evolved versions of SMGs. But this study showed that SMGs are larger and cooler than ULIRGs, which means that any evolutionary link between the two is unlikely.
The team calculated estimates of dust mass in these galaxies. Their estimates suggest that effectively all of the optical-to-near-infrared light from co-located stars is obscured by dust. They conclude that a common method in astronomy used to characterize astronomical light sources, called Spectral Energy Distribution (SED), may not be reliable when it comes to SMGs.
The fourth result is related to the evolution of galaxies. According to their analysis, it seems unlikely that SMGs can evolve into spiral or lenticular galaxies (a lenticular galaxy is midway between a spiral and an elliptical galaxy.) Rather, it appears that SMGs are the progenitors of elliptical galaxies.

The Pinwheel Galaxy (M101, NGC 5457) is a stunning example of a spiral galaxy. This study determines that there likely is no evolutionary link between sub-millimeter galaxies and spiral galaxies. Image: European Space Agency & NASA. CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=36216331

This study was a pilot study that the team hopes to extend to many other SMGs in the future.

April 22, 2017 by Evan Gough

Exciting New Views Of Opportunity’s Remarkable Landing Site

This image taken by the Mars Reconnaissance Orbiter's HiRise camera shows the bright landing platform left behind by NASA's Mars Exploration Rover Opportunity when it landed in 2004. Opportunity landed on the surface of Mars and then bounced and tumbled into the Eagle Crater. The image was taken on April 8, 2017. Image: NASA/JPL-Caltech/Univ. of Arizona

NASA’s eagle-eyed Mars Reconnaissance Orbiter (MRO) has captured orbital images of Opportunity’s Hole-In-One landing site, smack dab in the middle of Eagle Crater on the surface of Mars.

Opportunity arrived at Mars on January 25th, 2005. It’s landing was slowed by parachute, and cushioned by airbags. Once it hit the surface, it bounced its way into “Eagle Crater“, a feature a mere 22 meters across. Not a bad shot!

This is the first color image that the High Resolution Imaging Science Experiment (HiRise) has captured of Opportunity’s landing site. It shows the remarkable landing site inside the crater, where the landing pad was left behind after Opportunity rolled off of it and got going. It also shows the rover’s parachute and backshell.

It’s amazing that, given the relatively smooth surface in Opportunity’s landing area, the rover came to rest inside a small crater. When Opportunity “woke up” at its landing site, its first images were of the inside of Eagle Crater. This was the first look we ever got at the sedimentary rocks on Mars, taken by the rover’s navigation camera.

Opportunity's navigation camera took this picture, one of the rover's first, of the inside of Eagle Crater. Exposed Martian rocks are visible. NASA/JPL — Opportunity’s navigation camera took this picture, one of the rover’s first, of the inside of Eagle Crater. Exposed Martian rocks are visible. NASA/JPL

After leaving Eagle Crater, Opportunity took a look back and captured a panoramic image. Plainly visible is the rover’s landing pad, the exposed sedimentary rock, and the rover’s tracks in the Martian soil.

This panorama image, called "Lion King" was assembled from 558 images totalling over 75 megabytes. The rock outcrop, the landing pad, and the rover's tracks are all clearly visible. Image: NASA/JPL/Cornell — This panorama image, called “Lion King” was assembled from 558 images totalling over 75 megabytes. The rock outcrop, the landing pad, and the rover’s tracks are all clearly visible. Image: NASA/JPL/Cornell

MRO arrived at Mars a couple years later, and by that time Opportunity had already left its landing site and made its way south to the much larger Victoria Crater.

When the Mars Reconnaissance Orbiter arrived at Mars, 2 years after Opportunity touched down there, Opportunity had left Eagle Crater and travelled the 6 km to Victoria Crater. By NASA/JPL/University of Arizona - http://photojournal.jpl.nasa.gov/catalog/PIA08813, Public Domain, https://commons.wikimedia.org/w/index.php?curid=4211043 — When the Mars Reconnaissance Orbiter arrived at Mars, 2 years after Opportunity touched down there, Opportunity had left Eagle Crater and travelled the 6 km to Victoria Crater. By NASA/JPL/University of Arizona – http://photojournal.jpl.nasa.gov/catalog/PIA08813, Public Domain, https://commons.wikimedia.org/w/index.php?curid=4211043

Opportunity is still chugging along, doing valuable work. And so is the MRO and its HiRise instrument. At this point, Opportunity has to be considered one of the most successful scientific undertakings ever.

April 21, 2017April 28, 2017 by Evan Gough

Are Drylanders The Minority On Habitable Worlds?

Artist's depiction of a waterworld. A new study suggests that Earth is in a minority when it comes to planets, and that most habitable planets may be greater than 90% ocean. Credit: David A. Aguilar (CfA)

If we want to send spacecraft to exoplanets to search for life, we better get good at building submarines.

A new study by Dr. Fergus Simpson, of the Institute of Cosmos Sciences at the University of Barcelona, shows that our assumptions about exo-planets may be wrong. We kind of assume that exoplanets will have land masses, even though we don’t know that. Dr. Simpson’s study suggests that we can expect lots of oceans on the habitable worlds that we might discover. In fact, ocean coverage of 90% may be the norm.

At the heart of this study is something called ‘Bayesian Statistics’, or ‘Bayesian Probability.’

Normally, we give something a probability of occurring—in this case a habitable world with land masses—based on our data. And we’re more confident in our prediction if we have more data. So if we find 10 exoplanets, and 7 of them have significant land masses, we think there’s a 70% chance that future exoplanets will have significant land masses. If we find 100 exoplanets, and 70 of them have significant land masses, then we’re even more confident in our 70% prediction.

Is Earth in the range of normal when it comes to habitable planets? Or is it an outlier, with both large land masses, and large oceans? Image: Reto Stöckli, Nazmi El Saleous, and Marit Jentoft-Nilsen, NASA GSFC

But the problem is, even though we’ve discovered lots of exoplanets, we don’t know if they have land masses or not. We kind of assume they will, even though the masses of those planets is lower than we expect. This is where the Bayesian methods used in this study come in. They replace evidence with logic, sort of.

In Bayesian logic, probability is assigned to something based on the state of our knowledge and on reasonable expectations. In this case, is it reasonable to expect that habitable exoplanets will have significant landmasses in the same way that Earth does? Based on our current knowledge, it isn’t a reasonable expectation.

According to Dr. Simpson, the anthropic principle comes into play here. We just assume that Earth is some kind of standard for habitable worlds. But, as the study shows, that may not be the case.

“Based on the Earth’s ocean coverage of 71%, we find substantial evidence supporting the hypothesis that anthropic selection effects are at work.” – Dr. Fergus Simpson.

In fact, Earth may be a very finely balanced planet, where the amount of water is just right for there to be significant land masses. The size of the oceanic basins is in tune with the amount of water that Earth retains over time, which produces the continents that rise above the seas. Is there any reason to assume that other worlds will be as finely balanced?

Dr. Simpson says no, there isn’t. “A scenario in which the Earth holds less water than most other habitable planets would be consistent with results from simulations, and could help explain why some planets have been found to be a bit less dense than we expected.” says Simpson.

Simpson’s statistical model shows that oceans dominate other habitable worlds, with most of them being 90% water by surface area. In fact, Earth is very close to being a water world. The video shows what would happen to Earth’s continents if the amount of water increased. There is only a very narrow window in which Earth can have both large land masses, and large oceans.

Dr. Simpson suggests that the fine balance between land and water on Earth’s surface could be one reason we evolved here. This is based partly on his model, which shows that land masses will have larger deserts the smaller the oceans are. And deserts are not the most hospitable place for life, and neither are they biodiverse. Also, biodiversity on land is about 25 times greater than biodiversity in oceans, at least on Earth.

Simpson says that the fine balance between land mass and ocean coverage on Earth could be an important reason why we are here, and not somewhere else.

“Our understanding of the development of life may be far from complete, but it is not so dire that we must adhere to the conventional approximation that all habitable planets have an equal chance of hosting intelligent life,” Simpson concludes.

April 20, 2017April 28, 2017 by Evan Gough

Opportunity Leaving ‘Tribulation’ Behind

Opportunity took this panorama shot of "Rocheport Ridge" as it left Cape Tribulation. Rocheport is on the southern end of Cape Tribulation. Image:NASA/JPL-Caltech/Cornell Univ./Arizona State Univ.

You’d have to be an intrepid explorer to investigate something named ‘Cape Tribulation’. Opportunity, NASA’s long-lived rover on Mars’ surface, has been just that. But Opportunity is now leaving Cape Tribulation behind, after being in that area since late 2014, or for about 30 months.

Cape Tribulation is the name given to a segment of crater rim at Endeavour Crater, where Opportunity has been for over 5 1/2 years. During that time, Opportunity reached some important milestones. While there, it surpassed 26 miles in distance travelled, the length of a marathon race. It also reached its highest elevation yet, and in ‘Marathon Valley’, it investigated clay outcrops seen from orbit. Opportunity also had some struggles there, when its flash memory stopped working, meaning all data had to be transmitted every day, or lost.

Sol 3906, January 19, 2015. Summit panorama from Cape Tribulation from the Opportunity Mars Rover. Credit: NASA/Arizona State University.

Before reaching Cape Tribulation 30 months ago, Opportunity investigated other parts of Endeavour Crater called “Cape York,” “Solander Point” and “Murray Ridge.”

Some of the named features at Endeavour Crater. Image: NASA/JPL-Caltech/MSSS

The rover’s next destination is Perseverance Valley, where it will investigate how it was carved out billions of years ago: by water, by wind, or perhaps flowing material lubricated by water. Before leaving Cape Tribulation, Opportunity captured the panoramic image of Rochefort Ridge, a section of the Endeavour Crater rim marked by grooves on its side.”The degree of erosion at Rocheport is fascinating,” said Opportunity Deputy Principal Investigator Ray Arvidson, of Washington University in St. Louis. “Grooves run perpendicular to the crest line. They may have been carved by water or ice or wind. We want to see as many features like this on the way to Perseverance Valley as we can, for comparison with what we find there.”

Endeavour crater is about 22km in diameter, and Perseverance Valley is about 2 football fields long. The goal at Endeavour is to investigate its segmented rim, where the oldest rocks ever investigated on Mars are exposed. Since the beginning of April, Opportunity has travelled about 98 meters, to a point where Cape Tribulation meets the plain around the crater.

“From the Cape Tribulation departure point, we’ll make a beeline to the head of Perseverance Valley…” – Opportunity Deputy Principal Investigator Ray Arvidson

“From the Cape Tribulation departure point, we’ll make a beeline to the head of Perseverance Valley, then turn left and drive down the full length of the valley, if we can,” Arvidson said. “It’s what you would do if you were an astronaut arriving at a feature like this: Start at the top, looking at the source material, then proceed down the valley, looking at deposits along the way and at the bottom.”

It’s the nature of those deposits that can give vital clues to how Perseverance Valley was formed. Arvidson said, “If it was a debris flow, initiated by a little water, with lots of rocks moving downhill, it should be a jumbled mess. If it was a river cutting a channel, we may see gravel bars, crossbedding, and what’s called a ‘fining upward’ pattern of sediments, with coarsest rocks at the bottom.”

Opportunity, and its sister rover Spirit, arrived at Mars in 2004, with a planned mission length of 90 days. Opportunity has surpassed that by over 12 years, and continues to perform extremely well in the Martian environment.