News from Space: Planet Hunting Flower-Shaped Starshade

nasa-starshadeWith over 1800 extra-solar planets discovered in the past 30 years, the search for life beyond our Solar System has begun anew. Astronomers believe that every star in the galaxy has a planet, and that one fifth of these might harbor life. The greatest challenge, though, is in being able to spot these “Earth-like” exoplanets. Due to the fact that they emit very little light compared to their parent stars (usually less than one-millionth the level of radiance), direct imaging is extremely rare and difficult.

As such, astronomers rely predominantly on is what is known as Transit Detection – spotting the planet’s as they cross in front of the star’s disc. This too presents difficulties, because the transit method requires that part of the planet’s orbit intersect a line-of-sight between the host star and Earth. The probability that an exoplanet will be in a randomly oriented orbit that can allow for it be observed in front of its star is therefore somewhat small.

starshade-8Luckily, engineers and astronomers at NASA and other federal space agencies are considering the possibility of evening these odds with new technology and equipment. Once such effort comes from Princeton’s High Contrast Imaging Laboratory, where Jeremy Kasdin and his team are working on a revolutionary space-based observatory known as a “starshade” – a flower petal-shaped device that allows a telescope to photograph planets from 50,000 kilometers away.

Essentially, the starshade blocks light from distant stars that ordinarily outshine their dim planets, making a clear view impossible. When paired with a space telescope, the starshade adds a new and powerful instrument to NASA’s cosmic detection toolkit. The flower-shaped petals are part of what makes the starshade so effective. The starshade is also unique in that, unlike most space-based instruments, it’s one part of a two-spacecraft observation system.

starshade-foldedAs Dr. Stuasrt Shaklan, NASA Jet Propulsion Labratory’s lead engineer on the starshade project, explaned:

The shape of the petals, when seen from far away, creates a softer edge that causes less bending of light waves. Less light bending means that the starshade shadow is very dark, so the telescope can take images of the planets without being overwhelmed by starlight… We can use a pre-existing space telescope to take the pictures. The starshade has thrusters that will allow it to move around in order to block the light from different stars.

This process presents a number of engineering challenges that Shaklan and his team are working hard to unravel, from positioning the starshade precisely in space, to ensuring that it can be deployed accurately. To address these, his research group will create a smaller scale starshade at Princeton to verify that the design blocks the light as predicted by the computer simulations. Concurrently, the JPL team will test the deployment of a near-full scale starshade system in the lab to measure its accuracy.

starshade_petalsDespite these challenges, the starshade approach could offer planet-hunters many advantages, thanks in no small part to its simplicity. Light from the star never reaches the telescope because it’s blocked by the starshade, which allows the telescope system to be simpler. Another advantage of the starshade approach is that it can be used with a multi-purpose space telescope designed to make observations that could be useful to astronomers working in fields other than exoplanets.

As part of NASA’s New World’s Mission, the starshade engineers are optimistic that refining their technology could be the key to major exoplanet discoveries in the near future. And given that over 800 planets have been detected so far in 2014 – that’s almost half of the 1800 that have been detected in total – anything that can assist in their detection process at this point is likely to lead to an explosion in planetary discoveries.

And with one-fifth of these planets being a possible candidate for life… well, you don’t have to do the math to know that the outcome will be might exciting! In the meantime, enjoy this video from TED Talks, where Professor Jeremy Kasdin speaks about the starshade project:


Source:
ted.com, planetquest.jpl.nasa.gov, princeton.edu

News From Space: Birth of Black Hole Witnessed

big bang_blackholeWhen it comes to observational astronomy, scientists and cosmologists have been facing a sort of crisis of late. With so many instruments aimed at the heavens, recording what little information makes it all the way to Earth, simply observing distant stars has been providing diminishing returns. In order to keep moving forward, we must observe the most unusual and, in many cases, violent cosmic events so we can see some truly novel data.

This presents a bit of a challenge, since the the space industry can’t possibly set up enough telescopes to look at every part of the night sky all at once. With so much depth through which to zoom, it would seem a lost cause to try to capture unexpected, short-lived events. And yet, one such event, one that is truly cosmic in nature (no pun!), was captured just recently.

NASA's_Fermi,_Swift_See_'Shockingly_Bright'_Burst_(before_and_after_labels)It took place back in late November, when an “armada of instruments” from all over the world saw a massive gamma-ray burst originating from a point in space known as GRB 130427A. This burst was more powerful than what many researchers believed was theoretically possible, and is now thought to be the collapse of a giant star and the birth of a black hole.

The event has been described as a “Rosetta stone moment” by astronomers for a number of reasons. In addition to being a truly rare and awesome sight, this burst has also sent out information that astronomers will be studying for many years to come. And while it’s too soon to draw any real conclusions, there is already widespread excitement about the sheer newness of it.

blackhole_birthAnd yet, GRB 130427A only lasted about 80 seconds at observable intensities, so the fact that it was observed, letalone documented so thoroughly was truly surprising! This was all thanks to the Los Alamos National Laboratories in New Mexico, where six robotic cameras – collectively referred to as RAPTOR, or RAPid Telescopes for Optical Response – were able to respond in time to catch the event unfold.

The RAPTOR telescopes are networked together and all obey a central computer “brain”. Between their dedicated computing hardware and robotic swivel-mounts, they can turn to view any point in the sky in less than three seconds. As the world’s fastest “optical response” devices, RAPTOR’s telescopes are designed to make sure we don’t miss astronomical events when they happens, because in astronomy there are no second chances.

gamma-ray-burst The RAPTOR telescopes to ensure things aren’t missed by performing extremely diffuse, wide-angle sweeps of the sky to pick up hints at about where and when a major event is taking place. When one of the telescopes sees a hint of something good, it and the others quickly reorient and zoom to capture it in full detail. And with all six telescopes capturing the same event, the wealth of information gleamed is quite impressive.

The telescopes have different specializations as well. For example, the RAPTOR-T views all events through four aligned lenses with four different color filters. By looking at the differences in color distribution in the sample, RAPTOR-T can provide info about the distance to an event (by measuring Red Shift and Blue Shift) or about some elements of its environment.

grb130427aThis gamma ray burst is thought to be the brightest in decades, perhaps in a century. And if astronomers had missed it, it’s likely that nobody would have gotten the chance to capture one again. Luckily, the event was also seen by a number of other gamma ray detectors and x-ray telescopes. These included NASA’s Fermi, NuSTAR, and Swift satellites, all of which managed to see some portion of the event as it unfolded.

However, most telescopes joined in to view the event’s so-called afterglow, an incredibly violent occurrence where the newly-born black hole threw out debris and damage over a wide radius. For several hours, this radius glowed and astronomers watched as it faded. The intensity of high-energy gamma rays in that afterglow faded in tandem with its conventional light emissions.

This is one of the first useful bits of information provided by this event – the link between gamma rays and optical phenomena. But this is just one way that it could be astronomy’s latest Rosetta Stone observation. In the next few months, we can all look forward to a slew of exciting updates as astronomers sort through the implications of having witnessed the birth of an unprecedented singularity.

And in the meantime, check out this video of the gamma-ray burst, as observed by the RAPTOR All-Sky Monitor:


Source:
extremetech.com