news sciences

New Horizons has Ultima Thule in view

There are 2 highly processed images here, acquired by New Horizons on August 16, 2018. At left, a composite, produced by adding together 48 different exposures, each with an exposure time of 29.967 seconds. The predicted position of the Kuiper Belt object nicknamed Ultima Thule is indicated by the yellow crosshairs. At right, a magnified view of the region in the yellow box, after subtraction of background stars. There it is! Image via NASA/ Johns Hopkins University/ Southwest Research Institute.

The New Horizons spacecraft will remain forever in our hearts as the craft that provided our first glimpses of tiny Pluto and its system of moons, in 2015. Now New Horizons is headed toward its next target, a Kuiper Belt Object (KBO) called 2014 MU69, nicknamed Ultima Thule. New Horizons is moving fast. But space is vast, and distances in the outer solar system are great. So the New Horizons team was reassured earlier this month when the craft returned its first images of Ultima, showing the little KBO is very close to where scientists predicted it would be.

That’s good! It means New Horizons is being targeted in the right direction.

And so New Horizons will continue on its course toward this object, due to make its closest encounter on New Year’s Day, 2019.

Just how fast is New Horizons, by the way? At its launch on January 19, 2006, it was said to be the fastest spacecraft ever to leave Earth orbit. Since then, other craft have been determined to be faster. For example, the Parker Solar Probe, which launched earlier this month (August 12, 2018) is faster. Still, New Horizons is very fast, about 100 times faster than an earthly jet The tweet below, from 2015, is a great illustration.

Flying at 37k feet, this is what it would be like to look out the window of a 747 vs. an SR-71 vs. a New Horizons. pic.twitter.com/ChVsgK77Rl

— Clay Bavor (@claybavor) July 17, 2015

And now New Horizons has its first images of its next target, Ultima Thule, an object that had not been discovered yet when this craft was launched. The set of 48 images were transmitted home through NASA’s Deep Space Network.

NASA said the New Horizons team was thrilled – if not a little surprised – that New Horizons’ telescopic Long Range Reconnaissance Imager (LORRI) was able to see the small, dim object while still more than 100 million miles (160 million km) away, and against a dense background of stars. Hal Weaver, New Horizons project scientist, said in a statement:

The image field is extremely rich with background stars, which makes it difficult to detect faint objects. It really is like finding a needle in a haystack. In these first images, Ultima appears only as a bump on the side of a background star that’s roughly 17 times brighter, but Ultima will be getting brighter – and easier to see – as the spacecraft gets closer.

This first detection is important, NASA said, because the observations New Horizons makes of Ultima over the next four months will help the mission team refine the spacecraft’s course toward a closest approach to Ultima, at 12:33 a.m. EST on January 1, 2019.

The Ultima flyby will be the first-ever close-up exploration of a small Kuiper Belt object and the farthest exploration of any planetary body in history.

Ultima is clearly detected in this image, very close to where scientists predicted, indicating to the team that New Horizons is being targeted in the right direction. At the time of this observation, Ultima Thule was 107 million miles (172 million km) from the New Horizons spacecraft and 4 billion miles (6.5 billion km) from our sun. Image via NASA/ Johns Hopkins University/ Southwest Research Institute.

Bottom line: The New Horizons spacecraft acquired its first images of its next target – the Kuiper Belt Object called 2014 MU69, nicknamed Ultima Thule – on August 16, 2018.

Via Johns Hopkins University

from EarthSky https://ift.tt/2CenkXp

That’s good! It means New Horizons is being targeted in the right direction.

And so New Horizons will continue on its course toward this object, due to make its closest encounter on New Year’s Day, 2019.

Flying at 37k feet, this is what it would be like to look out the window of a 747 vs. an SR-71 vs. a New Horizons. pic.twitter.com/ChVsgK77Rl

— Clay Bavor (@claybavor) July 17, 2015

The image field is extremely rich with background stars, which makes it difficult to detect faint objects. It really is like finding a needle in a haystack. In these first images, Ultima appears only as a bump on the side of a background star that’s roughly 17 times brighter, but Ultima will be getting brighter – and easier to see – as the spacecraft gets closer.

The Ultima flyby will be the first-ever close-up exploration of a small Kuiper Belt object and the farthest exploration of any planetary body in history.

Bottom line: The New Horizons spacecraft acquired its first images of its next target – the Kuiper Belt Object called 2014 MU69, nicknamed Ultima Thule – on August 16, 2018.

Via Johns Hopkins University

from EarthSky https://ift.tt/2CenkXp

Hello, universe

Composite image by Karthik Easvur.

from EarthSky https://ift.tt/2wyXyXp

Composite image by Karthik Easvur.

from EarthSky https://ift.tt/2wyXyXp

How Gaia could help find Dyson spheres

View larger. | Artists’ concept of a Dyson sphere. Notice the little moon or planet on the left side, being ravaged for raw materials. This image – called Shield World Construction – is by Adam Burn. More about it here. Via FantasyWallpapers.com.

When contemplating extraterrestrial intelligence, one of the most tantalizing ideas is that a super-advanced alien civilization could build an enormous structure around its home star, to collect a significant portion of the star’s energy. This hypothetical megastructure is popularly known as a Dyson sphere. It’s a sci-fi-sounding concept, but some scientists have also seriously considered it. This week, a story emerged about how the European Space Agency’s Gaia mission – whose primary purpose is to create a 3D map of our Milky Way galaxy – might be instrumental in the search for Dyson spheres.

In the past, searches for Dyson spheres have focused on looking for signs of excess infrared or heat radiation in the vicinity of a star. That would be a telltale signature, but those attempts have come up empty, so far. The new peer-reviewed study – which was published in the Astrophysical Journal on July 18, 2018, and later described in Astrobites – proposes looking for Dyson spheres with little or no infrared excess. In other words, it describes a technique not attempted before.

Erik Zackrisson at Uppsala University in Sweden led the new study. It focuses on a type of Dyson sphere that would’ve been missed by prior searches focused on infrared radiation.

Suppose you were looking toward a Dyson sphere. What would you see? The visible light of the star would be reduced significantly since the Dyson sphere itself – by its nature – would mostly surround the star for purposes of energy collection. The star would continue shining; it would be shining on the inner portion of the Dyson sphere. Presumably, the star’s radiation would heat the sphere. According to earlier thoughts by scientists on the subject, a Dyson sphere should have a temperature between 50 and 1,000 Kelvin. At that temperature, radiation from the sphere would peak in infrared wavelengths.

That was the earlier idea, until Zackrisson’s study.

An all-sky view of the Milky Way and neighboring galaxies from the Gaia mission. This view includes measurements of nearly 1.7 billion stars. Image via Gaia Data Processing and Analysis Consortium (DPAC)/A. Moitinho/A. F. Silva/M. Barros/C. Barata – University of Lisbon, Portugal/H. Savietto – Fork Research, Portugal.

His study suggests the possibility that the sphere might be composed of a different kind of material than what had been previously supposed. Suppose this material had the ability to dim the star’s light equally at all wavelengths? That would make it a so-called gray absorber and would significantly affect methods used to search for Dyson spheres. If you measured the star’s distance spectrophotometrically – by comparing the star’s observed flux and spectrum to standard stellar emission models – then the measurements would suggest that the star is farther away than it actually is.

But then if you measured the star’s distance using the parallax method, you’d get a different number. The parallax method compares the apparent movement of a nearby against the star background, as Earth moves from one side of its orbit to another across a period of, say, six months. The size of a Dyson sphere could be determined by comparing the difference in distances between these two methods. The greater the difference, the greater the amount of the star’s surface that is being obscured by the sphere.

Now, thanks to new data from the Gaia mission, astronomers can do these kinds of comparisons, which could – in theory – detect a Dyson sphere. From the new study:

A star enshrouded in a Dyson sphere with a high covering fraction may manifest itself as an optically subluminous object with a spectrophotometric distance estimate significantly in excess of its parallax distance. Using this criterion, the Gaia mission will in coming years allow for Dyson sphere searches that are complementary to searches based on waste-heat signatures at infrared wavelengths. A limited search of this type is also possible at the current time, by combining Gaia parallax distances with spectrophotometric distances from ground-based surveys. Here, we discuss the merits and shortcomings of this technique and carry out a limited search for Dyson sphere candidates in the sample of stars common to Gaia Data Release 1 and Radial Velocity Experiment (RAVE) Data Release 5. We find that a small fraction of stars indeed display distance discrepancies of the type expected for nearly complete Dyson spheres.

In other words, using this new method, astronomers have found candidate Dyson sphere stars.

Graph showing distribution of covering fractions for all stars in the Gaia-RAVE database overlap (left) and just those stars with less than 10% error in their Gaia parallax distance and less than 20% error in their RAVE spectrophotometric distance (right). If the parallax distance is smaller than the spectrophotometric distance, that is interpreted this as a negative covering fraction, and could be an indication of a Dyson Sphere surrounding that star. Image via Zackrisson et al. 2018.

The Gaia mission is currently charting a three-dimensional map of our galaxy, providing unprecedented positional and radial velocity measurements with the highest accuracy ever. The goal is to produce a stereoscopic and kinematic census of about one billion stars in the Milky Way galaxy and throughout the Local Group of galaxies.

As it happens, these data are very useful when searching for Dyson spheres.

Using the parallax distances from the first data release of Gaia, Zackrisson and his colleagues compared that data to previously measured spectrophotometric distances from the Radial Velocity Experiment (RAVE), which takes spectra of stars in the Milky Way. This resulted in an estimate of what percentage of each star could be blocked by Dyson sphere material.

Illustration of how Gaia is measuring the distances to most stars in the Milky Way with unprecedented accuracy. Image via S. BRUNIER/ESO; GRAPHIC SOURCE: ESA.

Of course, figuring out if any of these could actually be Dyson sphere candidates required further analysis. Zackrisson and his team decided to focus on main-sequence stars (like the sun), spectral types F, G and K, and narrowed those down to those which displayed a potential blocking fraction greater the 0.7. Larger giant stars were removed from the data set since their spectrophotometric distances tend to be overestimated compared to main-sequence stars.

This alone left only six possible candidates. Those in turn were then narrowed down to only two, after eliminating four candidates due to problems with the data itself. One of those, the star TYC 6111-1162-1, was then considered to be the best remaining candidate.

Artist’s concept of Gaia in space. Image via D. DUCROS/ESA.

So… has the first Dyson Sphere been found? The simple answer is we don’t know yet. The star, a garden-variety late-F dwarf, seems to exhibit the sought-after characteristics, but more data is needed. No other glitch-related weirdness was found in the data, but the star was also found to be a binary system consisting of two stars (the other being a small white dwarf) which might explain the results, but none of that is certain yet. Additional study of the star will be required, including using future Gaia data releases, to determine what is really happening here. From the new study:

To shed light on the properties of objects in this outlier population, we present follow-up high-resolution spectroscopy for one of these stars, the late F-type dwarf TYC 6111-1162-1. The spectrophotometric distance of this object is about twice that derived from its Gaia parallax, and there is no detectable infrared excess. While our analysis largely confirms the stellar parameters and the spectrophotometric distance inferred by RAVE, a plausible explanation for the discrepant distance estimates of this object is that the astrometric solution has been compromised by an unseen binary companion, possibly a rather massive white dwarf. This scenario can be further tested through upcoming Gaia data releases.

What is a Dyson sphere?

An artist’s concept of a Dyson sphere, built by an advanced civilization to capture the energy of a star. Image via CapnHack, via energyphysics.wikispaces.com.

First step toward a Dyson sphere? Image via Flickr user langalex.

Proponents of solar power know that only a tiny fraction of the sun’s total energy strikes the Earth. What if we, as a civilization, could collect all of the sun’s energy? If so, we would use some form of Dyson sphere, sometimes referred to as a Dyson shell or megastructure. Physicist and astronomer Freeman J. Dyson first explored this idea as a thought experiment in 1960. Dyson’s two-page paper in the journal Science was titled Search for Artificial Stellar Sources of Infrared Radiation because he was imagining a solar-system-sized solar power collection system not as a power source for us earthlings, but as a technology that other advanced civilizations in our galaxy would, inevitably, use. Dyson proposed that searching for evidence of the existence of such structures might lead to the discovery of advanced civilizations elsewhere in the galaxy.

Freeman Dyson at the Long Now Seminar, San Francisco, October 5, 2005. Photo by Jacob Appelbaum/Wikimedia Commons.

In recent years, astronomers explored that possibility with a bizarre star, known to astronomers as KIC 8462852 – more popularly called Tabby’s Star for its discoverer Tabetha Boyajian. This star’s strange light was originally thought to indicate a possible Dyson sphere. That idea has been discarded, but, in 2018, other possibilities emerged, such as that of using the Gaia mission to search for Dyson spheres.

All of this is just to say that Dyson spheres – while in the realm of science fiction and scientific possibility during the 20th century – now seem real enough to astronomers that some are scrutinizing particular stars, looking for signs of them.

A solid, hollow shell around a star isn't mechanically possible. The simplest form of Dyson sphere might begin as a ring of solar power collections, sometimes called a Dyson ring. Image via Wikipedia.

The central dot in this image represents a star. The simplest form of Dyson sphere might begin as a ring of solar power collectors, at a distance from a star of, say, 100 million miles. This configuration is sometimes called a Dyson ring. Image via Wikimedia Commons.

So what are these odd megastructures, these Dyson spheres? Originally, some envisioned a Dyson sphere as an artificial hollow sphere of matter around a star, and Dyson did originally use the word shell. But Dyson didn’t picture the energy-collectors in a solid shell. In an exchange of letters in Science with other scientists, following his 1960 Science article, Dyson wrote:

A solid shell or ring surrounding a star is mechanically impossible. The form of ‘biosphere’ which I envisaged consists of a loose collection or swarm of objects traveling on independent orbits around the star.

As time passed, a civilization might continue to add Dyson rings to the space around its star, creating this form of relatively simple Dyson sphere. Image via Wikipedia.

As time passed, a civilization might continue to add Dyson rings to the space around its star, creating a relatively simple, but incredibly powerful, Dyson sphere. Image via Wikimedia Commons.

A Dyson sphere might be, say, the size of Earth’s orbit around the sun; we orbit at a distance of 93 million miles (about 150 million km). The website SentientDevelopments describes the Dyson sphere this way:

It would consist of a shell of solar collectors (or habitats) around the star. With this model, all (or at least a significant amount) of the energy would hit a receiving surface where it can be used. [Dyson] speculated that such structures would be the logical consequence of the long-term survival and escalating energy needs of a technological civilization.

And of course science fiction writers have had a field day writing about Dyson spheres. Dyson himself admitted he borrowed from science fiction before he began his technical exploration of the idea of a megastructure gathering energy from its star. Olaf Stapledon first mentioned this idea in his 1937 science fiction novel Star Maker, which Dyson apparently read and used as inspiration.

View larger. | Artist's concept of a Dyson sphere via SentientDevelopments.com

View larger. | Eventually, as a civilization evolves – aided by the boundless energy gathered from its star – its surrounding Dyson sphere will surely evolve as well, in ways that are hard to predict. This artist’s concept of a Dyson sphere is via SentientDevelopments.com.

What might astronomers look for, in the search for evidence of Dyson spheres in the space of our Milky Way galaxy? Even before the discovery of KIC 8462852 – feeling frustrated by decades of seeking radio signals from intelligent civilizations beyond Earth, and not finding any – a few astronomers in 2013 were contemplating new search strategy. Consider that if a system of solar power collectors – a megastructure – were put in place around a star, the star’s light, as seen from our perspective, would be altered. The solar collectors would absorb and reradiate energy from the star. Astronomers have spoken of seeking that reradiated energy.

Stephen Battersby at New Scientist wrote a great article about how astronomers search for Dyson sphere, using reradiated energy, released in April 2013. The article is available by subscription only, but if you search on the title (“Alien megaprojects: The hunt has begun”), you might find an alternative link.

There’s also a very cool diagram published in New Scientist that helps explain astronomers’ new search, which you can see here.

In 2018, scientists began speaking of using the European Space Agency’s Gaia mission to seek Dyson spheres. Read about that possibility here.

View larger. | Here is a completely fantastic artist's concept of a Dyson sphere. I like it. Notice the little moon on the left side, being ravaged for raw materials. Via FantasyWallpapers.com

View larger. | Artist’s concept of a Dyson sphere. Notice the little moon or planet on the left side, being ravaged for raw materials. This image – called Shield World Construction – is by Adam Burn. More about it here. Via FantasyWallpapers.com.

Bottom line: A Dyson sphere would consist of orbiting solar collectors in the space around the star of an advanced civilization. The goal would be to ensure a significant fraction of the star’s energy hits a receiving surface where it could be used to the civilization’s benefit. Freeman J. Dyson, who in 1960 became the first scientist to explore this concept, suggested that this method of energy collection be inevitable for advanced civilizations.

How to build a Dyson sphere in five (relatively) easy steps

from EarthSky https://ift.tt/19eUVwc

An artist’s concept of a Dyson sphere, built by an advanced civilization to capture the energy of a star. Image via CapnHack, via energyphysics.wikispaces.com.

First step toward a Dyson sphere? Image via Flickr user langalex.

Freeman Dyson at the Long Now Seminar, San Francisco, October 5, 2005. Photo by Jacob Appelbaum/Wikimedia Commons.

A solid shell or ring surrounding a star is mechanically impossible. The form of ‘biosphere’ which I envisaged consists of a loose collection or swarm of objects traveling on independent orbits around the star.

As time passed, a civilization might continue to add Dyson rings to the space around its star, creating a relatively simple, but incredibly powerful, Dyson sphere. Image via Wikimedia Commons.

It would consist of a shell of solar collectors (or habitats) around the star. With this model, all (or at least a significant amount) of the energy would hit a receiving surface where it can be used. [Dyson] speculated that such structures would be the logical consequence of the long-term survival and escalating energy needs of a technological civilization.

There’s also a very cool diagram published in New Scientist that helps explain astronomers’ new search, which you can see here.

In 2018, scientists began speaking of using the European Space Agency’s Gaia mission to seek Dyson spheres. Read about that possibility here.

How to build a Dyson sphere in five (relatively) easy steps

from EarthSky https://ift.tt/19eUVwc

‘No-deal’ Brexit: what the Government’s plans could mean for cancer treatment, care and research

Brexit dominated the headlines last week, as the Government published the first in a series of plans for how it will respond if the UK doesn’t reach a deal with the European Union by the end of this year – a so-called ‘no-deal’ Brexit.

If there is no deal, the planned 18 months in which the UK would keep EU laws so organisations and business can adapt would be lost, and on March 29 the UK would stop being an EU member overnight. The standards and rules for how the UK trades and cooperates with the EU would also immediately stop applying.

So how would a no-deal Brexit affect cancer patients and research?

What came up for cancer?

The key areas for cancer patients and research in the latest batch of notices were the supply of cancer medicines, approving new drugs and clinical trials.

Now, the UK follows the EU on the licensing of new medicines, ensuring patients have swift access to safe and effective new treatments as soon as they come to market.

The UK also works with EU countries on clinical trials. This is particularly important for rare and childhood cancers, when there often aren’t enough patients in an individual country to run trials that are big enough to give clear results.

A big concern is that losing this cooperation could lead to delays for UK patients getting the newest medicines, or hinder international clinical trials where patients get access to the most innovative treatments.

And from the notices released last week, the Government seem to agree. They confirm that, even if there is no deal, the UK will continue to use EU standards on medicines and clinical trials in the short term. This should mean UK patients can continue to access vital treatments whatever happens.

But even with these steps, the notices make clear that a no deal would still cause disruption – and that drugs companies should stockpile medicines just in case.

What happens next?

We’re expecting around 50 further no deal notices, released in two more batches in September.

One issue we’ll be keeping an eye on is immigration. Free movement around Europe is essential for cancer research, allowing scientists to work in and collaborate with labs in different countries.

About half of the researchers and PhD students we fund are from outside of the UK. And we’d like the Government to guarantee the rights of EU citizens in the UK, to end the uncertainty for our scientists and make sure that vital cancer research can continue.

And while preparing for a no deal is important, the priority now for both the UK and the EU is to reach a deal. They were hoping to have this done by the middle of October, when European leaders meet in Brussels for a summit. But progress has been slower than expected, and a deal is more likely to come in November or even December.

This deal would sort out the transition period and allow business to go on largely as normal after March 29. This would be much better for cancer patients than a no deal, ensuring that they continue to have access to new treatments and opportunities to join clinical trials.

After this deal is reached the UK and EU would go back to negotiations, fleshing out the details of the future relationship. Big issues like trade will then be decided, alongside how the UK works with the EU on medicines, research and health.

Find out more about our work to ensure the best deal for cancer patients and research

Mark Heffernan is a public affairs manager at Cancer Research UK

from Cancer Research UK – Science blog https://ift.tt/2MVvhVx

So how would a no-deal Brexit affect cancer patients and research?

What came up for cancer?

The key areas for cancer patients and research in the latest batch of notices were the supply of cancer medicines, approving new drugs and clinical trials.

Now, the UK follows the EU on the licensing of new medicines, ensuring patients have swift access to safe and effective new treatments as soon as they come to market.

But even with these steps, the notices make clear that a no deal would still cause disruption – and that drugs companies should stockpile medicines just in case.

What happens next?

We’re expecting around 50 further no deal notices, released in two more batches in September.

One issue we’ll be keeping an eye on is immigration. Free movement around Europe is essential for cancer research, allowing scientists to work in and collaborate with labs in different countries.

Find out more about our work to ensure the best deal for cancer patients and research

Mark Heffernan is a public affairs manager at Cancer Research UK

from Cancer Research UK – Science blog https://ift.tt/2MVvhVx

Cassiopeia points to Andromeda galaxy

Tonight, if you have dark sky, try star-hopping to the Andromeda galaxy from the constellation Cassiopeia the Queen. If your sky is truly dark, you might even spot this hazy patch of light with no optical aid, as the ancient stargazers did before the days of light pollution.

What if your sky is more lit up, and you can’t find the Andromeda galaxy with the eyes alone? Some stargazers use binoculars and star-hop to the Andromeda galaxy via this W-shaped constellation.

Cassiopeia appears in the northeast sky at nightfall and early evening, then swings upward as evening deepens into late night. In the wee hours before dawn, Cassiopeia is found high over Polaris, the North Star. Note that one half of the W is more deeply notched than the other half. This deeper V is your “arrow” in the sky, pointing to the Andromeda galaxy.

The Andromeda galaxy is the nearest large spiral galaxy to our Milky Way. It’s about 2.5 million light-years away, teeming with hundreds of billions of stars.

Enjoying EarthSky so far? Sign up for our free daily newsletter today!

View larger. | Josh Blash shot this in 2014. He wrote, “M31, the Andromeda Galaxy. I used 29 frames shot at 90mm and tracked for 60 seconds each, then stacked them using the DeepSkyStacker software.” See more photos by Josh Blash on Facebook.

View larger. | Draw an imaginary line from the star Kappa Cassiopeiae (abbreviated Kappa) through the star Schedar, then go about 3 times the Kappa-Schedar distance to locate the Andromeda galaxy (Messier 31).

Bottom line: You can find the Andromeda galaxy using the constellation Cassiopeia as a guide. Remember, on a dark night, this galaxy looks like a faint smudge of light. Once you’ve found it with the unaided eye or binoculars, try with a telescope – if you have one.

Use the Great Square of Pegasus to find the Andromeda galaxy