Universe Today

October 25, 2013December 23, 2015 by Shannon Hall

Changing the Paradigm: Exoplanet Interview with Dr. Sara Seager

Planetary Scientist Sara Seager. Image courtesy MIT.

Astronomers have now discovered one thousand extrasolar planets, reaching a milestone in modern astronomy. (See a recent Universe Today article on the subject.) While many have contributed to this achievement, Dr. Sara Seager of MIT has played a large role over the past two decades by contributing vastly to the field of exoplanet characterization. Her theoretical work led to the first detection of an exoplanet atmosphere.

The following is a condensed interview I held with Seager earlier this week.

What first pulled you in to the field of astronomy?
When I was 10 I got to see a really dark sky (well outside her hometown of Toronto, Canada). I stepped out in the middle of the night and I just saw so many stars. I wish you and everyone could see that. So many stars, I just couldn’t believe it.

You were working at Harvard for your PhD in the mid ‘90s when we first detected exoplanets. What was that like?
The mood was quite different. Today everybody wants to talk about it (exoplanets) and write about it. There’s a lot of hype. But back then it was very quiet.

There was a huge amount of skepticism too. People don’t like change. I want you to imagine a world where the gas giants like Jupiter and Saturn are very far from the star and the terrestrial planets like Earth, Mercury, Venus, and Mars are very close to the star. People had constructed theories on how planetary bodies form based on that one example.

So when the first planets around sun-like stars were found, they were Jupiter-mass planets, but they were several times closer to their star than Mercury is to our Sun. It offended all thoughts, theories, and paradigms … As scientists we’re supposed to be skeptical and push back on new discoveries and theories that are upsetting the system. There was huge skepticism.

An exoplanet seen from its moon (artist's impression). Via the IAU. — An exoplanet seen from its moon (artist’s impression). Via the IAU.

How difficult was it during this time to work on exoplanets?
Many people, including my graduate student peers and faculty said, “Why are you doing this (working on exoplanet research)? This is not going to happen. And even if exoplanets are real we’re never going to be able to study their atmospheres,” which is what my PhD was on.

What pushed you through despite all the skepticism?
Ironically, I was not committed to a career in science. I didn’t feel like I needed to be involved with something that was at the 100 percent certainty level. I was free because I didn’t have a plan. I had nothing to lose by doing something I thought was really cool and exciting.

When you’re doing a PhD you’re really learning how to answer a tough question. Usually if you do a homework set in high school, or college, there’s already a known answer. But when you’re doing a PhD, if you’re asking a really hard question that has never been asked before you’re answering that question with your own tools that you’ve developed yourself.

At that time, I knew… the real thing is not just what you’re working on but it’s the tools that you’re using and the things that you’re learning. At the end of the day if you don’t stay in science you have gained a skill that most people don’t have.

Artist concept of an exoplanet. Credit: David A. Hardy.

What changed then? What kept you in science after graduate school?
I had freedom and really enjoyed what I was doing.

What is your motivation for studying exoplanets? Why should we study exoplanets?
We want to know: Are we alone? We want to know if there is life beyond earth. Eventually we will have dozens to hundreds of potential earth-like planets to study in detail. We want to look at their atmospheres for signs of life by way of biosignature gases.

What do you think is the likelihood that we will discover an earth-like planet orbiting a sun-like star?
Well, it really just depends if we can rally resources and interest in doing this problem. We think we know how to find an earth-like planet around a sun-like star. But it’s a very very very hard endeavor. We think that the earths are out there. It’s just a matter of building the sophisticated space telescopes that we need.

So what are the chances? It’s really more of a political and economical question more than anything else. I think it’s inevitable that eventually we will find one.

Do you have a favorite planet?
I always like to say my favorite planet is the next planet. We have a sort of ADD (attention deficit disorder) in this field where we’re propelled and motivated forward by finding the next exciting planet.

Artist's impression of exoplanets around other stars. Credits: ESA/AOES Medialab — Artist’s impression of exoplanets around other stars. Credits: ESA/AOES Medialab

We’ve reached a huge milestone in astronomy of detecting one thousand exoplanets. What does this milestone mean to you?
There’s a caveat here, an uncertainty. We don’t know which one is going to be number one thousand because we don’t agree on the definition of a planet. And even if we did, there’s an uncertainty in the mass and size measurements such that some objects that are called planets probably aren’t planets depending on what definition you want. Occasionally a planet is retracted.

But in general, we’re about to pass the one thousandth mark. What do I think? I think it’s phenomenal. I mean I’m so excited.

The study of exoplanets really started as a field where no one wanted to work on it. People thought it was never going to happen, they thought even if there were real planets we’d never get any measurements beyond stamp collecting – a derogatory phrase we sometimes use in astronomy for science that is not that useful. You just find discoveries and they pile up because you don’t know what to do with them.

We’ve changed the paradigm of planet formation, found exotic types of planets, and we’re right on our way to finding another Earth. So I think it couldn’t be better.

October 25, 2013December 23, 2015 by Nancy Atkinson

Watch Live: Defending Earth from Asteroids

Asteroid mining concept. Credit: NASA/Denise Watt

Live streaming video by Ustream

We know that hundreds of thousands of asteroids orbit the Sun, and a very few have a high risk of striking Earth. There are also asteroids that haven’t been discovered yet that can surprise us, as evidenced by the explosion over Chelyabinsk, Russia, last February. This event was confirmation that an asteroid strike is a risk we do face. But also, how do scientists counter the pseudo-scientific claims and fears that asteroids seem to generate? And what opportunities do asteroids provide for mining useful resources?

Watch live today (Friday, October 25, 2013) at 15:00 UTC (11 am EDT) as astrophysicist Neil deGrasse Tyson, astronauts Rusty Schweickart, Tom Jones, Ed Lu, Soichi Noguchi and others discuss the research and the steps that are being taken to avoid these potential natural disasters. With current space technology, scientists know how to deflect the majority of hazardous near-Earth objects, but these technologies have not yet been tested in space, and prevention is only possible if nations work together on detection and deflection.

This webcast is sponsored by the American Museum of Natural History. You can see their webpage about this event here.

October 25, 2013December 23, 2015 by Elizabeth Howell

What Caused The Spacesuit Leak? Astronauts Are Working To Hunt That Down

NASA astronauts Mike Hopkins and Karen Nyberg (edge of picture, at left) examine a faulty spacesuit aboard the International Space Station during Expedition 37 in October 2013. In July 2013, Italian astronaut Luca Parmitano had to abort a spacewalk after a water leak arose while wearing the spacesuit. The cause is still under investigation. Credit: NASA/YouTube (screenshot)

Here’s the latest attempt to hunt down the water leak that aborted Luca Parmitano’s spacewalk in July: two astronauts aboard the International Space Station removed and replaced a fan pump and water separator inside the spacesuit earlier this week.

All spacewalks with NASA suits are on hold while the agency investigates the leak, and they have been trying mightily. In late July, then on-station NASA astronaut Chris Cassidy demonstrated how the pool of water spread within the helmet (as you can see in these YouTube videos).

This week, on-orbit NASA astronauts Mike Hopkins and Karen Nyberg delved further. While the astronauts are trained before their missions on some suit repairs, this particular type was not something that was covered before they left Earth. After Mission Control walked them through what to do, the astronauts proceeded cautiously as they did the work, NASA said.

“Our engineering teams have identified several different components of the suit, designing a big fault tree, and this is just one of the components that we think could have contributed to the leak in the suit,” said Alex Kanelakos, an extra-vehicular activity flight controller and astronaut instructor, in a new YouTube video.

“Specifically, the water separator is what we’re concentrating our efforts on today.”

As Kanelakos explained, a motor inside the suit drives the fan pump and water separator. The fan circulates oxygen, and the pump pumps the coolant fluid. The water separator, meanwhile, takes out moisture (water) from the ventilation loop and gas that could be trapped inside the water coolant loop. The dried-out air is then returned to the crew member for breathing, and the cycle continues.

Astronaut Chris Cassidy works with Luca Parmitano's spacesuit, which had a water leak on July 16, 2013. Credit: NASA — Astronaut Chris Cassidy works with Luca Parmitano’s spacesuit, which had a water leak on July 16, 2013. Credit: NASA

In September, Cassidy told Universe Today that the spacesuit is expected to come back to Earth during a future SpaceX Dragon cargo flight. That type of spacecraft is (unusually among space trucks) designed to survive re-entry in the atmosphere, allowing engineers on the ground to examine the spacesuit after it comes back.

Cassidy added that the situation was serious, and he supported NASA’s decision to end the spacewalk (which he was also participating in.) He didn’t think, however, that Parmitano was in immediate danger of drowning. For his part, Parmitano wrote a blog post on the European Space Agency website after his spacewalk, saying that space is an “inhospitable” arena.

Italian astronaut Luca Parmitano during a spacesuit fit check before his mission. Credit: NASA

As any astronaut is trained to do, Parmitano did consider other contingencies while the leak was happening, he wrote:

“The only idea I can think of is to open the safety valve by my left ear: if I create controlled depressurisation, I should manage to let out some of the water, at least until it freezes through sublimation, which would stop the flow. But making a ‘hole’ in my spacesuit really would be a last resort,” he wrote.

That fix, however, was not implemented as Parmitano and Cassidy made their way back to the station in time for their crewmates to repressurize the hatch and bring their Italian crewmate safely inside.

Besides investigating the spacesuit, NASA has an ongoing parallel investigation to look at “lessons learned” from the mishap and ways of implementing procedures to stop such an incident from happening again.

October 24, 2013December 23, 2015 by Nancy Atkinson

Why Is Comet ISON Green?

Recent images of Comet ISON along with spectral data. Credit and copyright: Chris Schur.

Undoubtedly, you’ve been seeing the recent images of Comet ISON now that it is approaching its close encounter with the Sun on November 28. ISON is currently visible to space telescopes like the Hubble and amateur astronomers with larger telescopes. But you might be wondering why many images show the comet with a green-ish “teal” or blue-green color.

Amateur Astronomer Chris Schur has put together this great graphic which provides information on the spectra of what elements are present in the comet’s coma.

For the conspiracy theorists out there, the green color is actually a good omen, and lots of comets display this color. The green color is a sign the comet is getting more active as gets closer to the Sun – meaning it is now putting on a good show for astronomers, and if it can continue to hold itself together, it might become one of the brightest comets in the past several years.

“ISON’s green color comes from the gases surrounding its icy nucleus,” says SpaceWeather.com’s Tony Phillips. “Jets spewing from the comet’s core probably contain cyanogen (CN: a poisonous gas found in many comets) and diatomic carbon (C2). Both substances glow green when illuminated by sunlight in the near-vacuum of space.”

Comet ISON on October 4, 2013 as seen over Arizona, viewed with a 12.5" telescope, over an hour exposure time. Credit and copyright: Chris Schur. — Comet ISON on October 4, 2013 as seen over Arizona, viewed with a 12.5″ telescope, over an hour exposure time. Credit and copyright: Chris Schur.

Both are normally colorless gases that fluoresce a green color when excited by energetic ultraviolet light in sunlight.

And if those poisonous gasses sound dangerous, don’t worry. They are spread out in space much too thinly to touch us here on Earth. So don’t fall prey to fear mongers who are out to bilk the masses – like people did in 1910 when Comet Halley made a return to the skies and swindlers pitched their ‘gas masks’ and special ‘comet pills’ for protection. And of course, nothing happened.

But back to the color. Chris Schur provided this info along with his graphic:

Your readers may appreciate knowing why comets can appear this color. The background image is the shot I took with my 12.5″ and an ST10xme CCD camera for 20 minutes in mid-October. A pale coloration of the front of the coma is seen. To the lower left is a shot with the same instrument but with a 100 lpmm (line pair per millimeter) diffraction grating in front of the CCD chip to break out the spectra of the objects in the entire field.

Here ISON is faintly seen to the left of center, and the first order spectra a band to its right. But the real answer comes when we use the software called Rspec to analyze this band of light. The result is on the lower right. Normally reflected sunlight is rather flat and bland, and mostly that is what ISON is right now, reflected from dust. But labeled are two humps in the blue and green parts of the spectrum labeled “C2” for a carbon molecule. This blue/green emission pair is what gives ISON the color.

Chris notes that as the comet nears the Sun, astronomers and astrophotographers will be able to resolve more spectral details in the comet. “It will be exciting to watch the changes as more molecules pop out,” Chris said via email, “and possibly when it is closest to the Sun, we just may see some metal lines like iron or magnesium from MELTED vaporized rock. How exciting!”

And for those who insist there is something nefarious about Comet ISON, take a look at this FAQ from our friend Stuart Atkinson, who hosts the great site Waiting for ISON. He addresses the many conspiracy theories that are out there regarding this comet.

October 24, 2013December 23, 2015 by Elizabeth Howell

‘Light Echos’ Reveal Old, Bright Outbursts Near Milky Way’s Black Hole

X-ray emissions from the supermassive black hole in the center of the Milky Way galazy, about 26,000 light years from Earth. Credit: NASA/CXC/APC/Université Paris Diderot/M.Clavel et al

How’s that for a beacon? NASA’s Chandra X-ray Observatory has tracked down evidence of at least a couple of past luminous outbursts near the Milky Way’s huge black hole. These flare-ups took place sometime in the past few hundred years, which is very recently in astronomical terms.

“The echoes from Sagittarius A were likely produced when large clumps of material, possibly from a disrupted star or planet, fell into the black hole,” the Chandra website stated.

“Some of the X-rays produced by these episodes then bounced off gas clouds about 30 to 100 light years away from the black hole, similar to how the sound from a person’s voice can bounce off canyon walls. Just as echoes of sound reverberate long after the original noise was created, so too do light echoes in space replay the original event.”

The astronomers saw evidence of “rapid variations” in how X-rays are emitted from gas clouds circling the hole, revealing clues that the area likely got a million times brighter at times.

Check out more information on Chandra’s website.

October 24, 2013December 23, 2015 by Elizabeth Howell

Japanese ‘Space Cannon’ On Track For Aiming At An Asteroid: Reports

Painting of Asteroid 2012 DA14. © David A. Hardy/www.astroart.org

Watch out, asteroid 1999 JU3: you’re being targeted. As several media reports reminded us, the Japan Aerospace Exploration Agency (JAXA)’s Hayabusa-2 asteroid exploration mission will carry a ‘space cannon’ on board — media-speak for the “collision device” that will create an artificial crater on the asteroid’s surface.

“An artificial crater that can be created by the device is expected to be a small one with a few meters in diameter, but still, by acquiring samples from the surface that is exposed by a collision, we can get fresh samples that are less weathered by the space environment or heat,” JAXA states on its website.

Reports indicate JAXA is on schedule to, er, shoot this thing into space for a 2018 rendezvous with an asteroid. The spacecraft will stick around the asteroid for about a year before heading back to Earth in 2020. The overall aim is to learn more about the origin of the solar system by looking at a C-type asteroid, considered to be a “primordial body” that gives us clues as to the early solar system’s makeup.

Check out more on Hayabusa-2 on JAXA’s website.

October 24, 2013December 23, 2015 by Nancy Atkinson

Beautiful Comet ISON Timelapse and Recent Images

Comet ISON, as seen on October 21, 2013 from Marion, Ohio, USA, using a QHY9 monochrome CCD camera and TEC 140 F7, 5 inch Refractor telescope. Credit and copyright: Cliff Spohn and Terry Hancock.

This beautiful new view of Comet ISON comes from a collaborative effort between astrophotographers Cliff Spohn in Ohio and Terry Hancock in Michigan, taken on October 21, 2013. “The first time in almost two weeks that we have had a break in the clouds and rain we could not miss this rare opportunity to capture ISON using Cliff’s equipment,” said Terry via email. “Credit goes to Cliff for capturing the object while I did the calibration, stacking in CCDStack post processing in CS5 and video editing.”

You can see a timelapse video below, covering 93 minutes of imaging, again on October 21. It’s obvious ISON is still intact and it continues to bright, as it is currently about magnitude 9.

More recent images:

Update: This new one is just in from astrophotographer Damian Peach, and its a beauty! Taken on October 24.

Comet C/2012 S1 ISON captured passing fairly close to the bright barred spiral galaxy M95 in Leo on October 24, 2013. Credit and copyright: Damian Peach.

Comet ISON C/2012 S1, Mars, & Regulus on 10-18-2013 Warrenton, Virginia 6:27am EST Canon Rebel Xsi & 170mm lens F6.3, ISO 400, 6 minutes 6 secs. Credit and Copyright: John Chumack. — Comet ISON C/2012 S1, Mars, & Regulus on 10-18-2013
Warrenton, Virginia 6:27am EST
Canon Rebel Xsi & 170mm lens F6.3, ISO 400,
6 minutes 6 secs. Credit and Copyright: John Chumack.

From John Chumack: “I just had to try just a telephoto on Comet ISON while it was near Mars,” John said via email. This view shows Comet ISON (C/2012 S1) near Mars and Regulus, the brightest star in the constellation Leo. This image was taken on October 18, 2013 from
Warrenton, Virginia at 6:27am EST looking over Washington D.C.

Triple conjunction of Comet ISON, Mars, Regulus on October 14, 2013, as seen from Payson, Arizona, USA. Credit and copyright: Chris Schur.

This nice image comes from Chris Schur from Arizona, taken on October 14, and is also of the conjunction. “As you may recall, on this date of 10/14 the three objects were in a perfect line going from south to north in Leo,” Chris said via email. “What a spectacular sight in the 11 x 80 binoculars! While the comet was quite faint, a short 1/4 degree of tail could be seen, and the gorgeous blue and orange colors of the planets.”

Chris used a Canon Xti, ASA800 with 10 minutes total integration time, with a 80mm f/4.8 Ziess APO refractor on a Televue GEM. Taken from Payson, Arizona at 5,100 feet elevation.

October 24, 2013December 23, 2015 by Jason Major

Watch the Sun Split Apart

Canyon of Fire on the Sun, Credit: NASA/SDO/AIA)

Here’s your amazing oh-my-gosh-space-is-so-cool video of the day — a “canyon of fire” forming on the Sun after the liftoff and detachment of an enormous filament on September 29-30. A new video, created from images captured by the Solar Dynamics Observatory (SDO) and assembled by NASA’s Goddard Space Flight Center, shows the entire dramatic event unfolding in all its mesmerizing magnetic glory.

Watch it below:

Solarrific! (And I highly suggest full-screening it in HD.) That filament was 200,000 miles long, and the rift that formed afterwards was well over a dozen Earths wide!

Captured in various wavelengths of light by SDO’s Atmospheric Imaging Assembly (AIA) the video shows the solar schism in different layers of the Sun’s corona, which varies greatly in temperature at different altitudes.

According to the description from Karen Fox at GSFC:

“The red images shown in the movie help highlight plasma at temperatures of 90,000° F and are good for observing filaments as they form and erupt. The yellow images, showing temperatures at 1,000,000° F, are useful for observing material coursing along the sun’s magnetic field lines, seen in the movie as an arcade of loops across the area of the eruption. The browner images at the beginning of the movie show material at temperatures of 1,800,000° F, and it is here where the canyon of fire imagery is most obvious.”

Now, there’s not really any “fire” on the Sun — that’s just an illustrative term. What we’re actually seeing here is plasma contained by powerful magnetic fields that constantly twist and churn across the Sun’s surface and well up from its interior. The Sun is boiling with magnetic fields, and when particularly large ones erupt from deep below its surface we get the features we see as sunspots, filaments, and prominences.

When those fields break, the plasma they contained gets blasted out into space as coronal mass ejections… and this is what typically happens when one hits Earth. (But it could be much worse.)

Hey, that’s what it’s like living with a star!

Stay up to date on the latest solar events on the SDO mission page here.

October 24, 2013December 23, 2015 by Nancy Atkinson

Video: Spider Flown in Space Has Trouble Readapting to Gravity

Nefertiti, the "Johnson Jumper" spider hunting for flies inside her habitat on board the International Space Station (ISS). (NASA)

Astronauts have said adapting to weightlessness is much easier than readapting to gravity when they returned to Earth. Muscle weakness, wobbly legs, and feeling like the room is spinning is common after long duration spaceflight, not to mention the long-term issues like bone loss, diminished eyesight, and a heart that has to recondition itself to pump blood harder to overcome gravity. As Canadian Chris Hadfield said, “My body was quite happy in space without gravity.”

It turns out spiders have similar issues. This Phiddipus Johnsoni, or red-backed jumping spider named Nefertiti is shown walking and preying on flies in her habitat while in orbit on the International Space Station and then doing the same while readapting to gravity on Earth. While trying to capture its prey, it ends up flopping awkwardly onto its back. No more flying like SuperSpider.

Nefertiti was in space 100 days in 2012 as part of a student-initiated science experiment of YouTube’s Space Lab, an online video contest. After returning home, this spidernaut was sent to the Smithsonian Institution’s National Museum of Natural History in Washington, D.C. and was part of exhibition of the first jumping spider to survive the trip to space. Unfortunately Nefertiti died just a few days after being sent to the museum.

October 24, 2013December 23, 2015 by Elizabeth Howell

Space Trucks! A Pictorial History Of These Mighty Machines

A view of Orbital Sciences' Cygnus spacecraft while it was being released from the International Space Station on Oct. 22. Credit: NASA/Karen Nyberg

Cargo resupply ships are vital for space exploration. These days they bring food, experiments and equipment to astronauts on the International Space Station. And in recent years, it hasn’t just been government agencies sending these things up; SpaceX’s Dragon spacecraft and (just this week) Orbital Sciences’ Cygnus spacecraft brought up cargo of their own to station in recent months.

NASA just published a brief timeline of (real-life) cargo spacecraft, so we thought we’d adapt that information in pictorial form. Here are some of the prominent members of that elite group. Did we miss anything? Let us know in the comments.