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Readers’ wildlife photos

Why Evolution is True Feed - Sat, 12/09/2017 - 5:45am

Just a reminder to send in your photos. Today’s come from reader Mark Richardson’s decade-old trip to Alaska. His notes are indented:

These are a mixture of wildlife and landscape photos from a 2006 fishing trip in Alaska. We flew into Anchorage and drove south toward the Kenai peninsula. We met our fishing guides at the Soldatna airport and took a small airplane up the Cook inlet to a secluded fishing cabin. We were fishing for Coho (silver) salmon as they were heading towards fresh water rivers to spawn. Since they were still in the ocean, they were feeding (salmon stop feeding once they hit fresh water). We were catching them using lightweight fly rods. It was a hoot! The first three are photos of wildlife, two of which are common animals seen on WEIT. The rest are landscapes- the first six were taken from the plane. A red fox (Vulpes vulpes) that hung around our camp looking for scraps.  One of the fishing guides fed it pieces of steak, so no wonder it liked to loiter.   A juvenile Grizzly bearUrsus arctos, combing the beach for noms. Grizzly bears were a common sight and this fact kept us all alert.
The ubiquitous (at least in Alaska) bald eagle Haliaeetus leucocephalus. Soldatna seen from the plane shortly after take-off.

A colorful landscape from the plane of an alpine lake. Big country up in Alaska- there is a glacier in the background. A beautiful braided river. A steaming volcano in the far background. The runway at our fishing camp- not cool! Low tide, big sky and two fishermen. Not wildlife…just some essentials for the perfect fishing trip!
Categories: Science

Saturday: Hili dialogue

Why Evolution is True Feed - Sat, 12/09/2017 - 4:30am

It’s the weekend: Saturday, December 9, 2017, and a week before I arrive in India. It’s also Nation Pastry Day and, according to the UN, International Anti-Corruption Day. I’m at work early as I have to do shopping later for India (my friends want some stuff not available there), and I’m waking up with a homemade giant latte in my favorite cup:

On this day in, 1531, The Virgin of Guadalupe made her first appearance: to Juan Diego Cuauhtlatoatzin in Mexico City.  On December 9, 1793, the first daily newspaper in America, the American Minerva, was established by Noah Webster.  In 1897, Parisian activist Marguerite Durand founded the feminist daily newspaper La Fronde.  Exactly seven years later, France passed the law separating church and state.  On this date in 1946, the Indian Assembly met to begin writing the Constitution of India.  And on December 9, 1960, the first episode of Coronation Street—the world’s longest-running t.v. soap opera (it’s still on), was broadcast in the UK.  And it’s a banner day in science and medicine: on this day in 1979, the World Health organization certified that the smallpox virus had been completely eradicated from the planet—still the only human disease driven to extinction. Here’s the last person to get it: two-year-old Rahima Banu from Bangladesh, who contracted the disease in 1975. She survived, and now has four children of her own:

But we’ve also driven an animal disease to extinction; do you know what it is? Finally, on this day in 1987, the first Intifada began in the Gaza Strip and West Bank.

Notables born on this day include John MIlton (1608), Peter Kropotkin (1842), Fritz Haber (1868), Joseph Pilates (1883; yes the inventor of the racist discipline of Pilates), Tip O’Neill (1912), Kirk Douglas (1916), Judi Dench (1934), and Donny Osmond (1957). Those who fell asleep on this day include Anthony van Dyck (1641), Edith Sitwell (1964), Branch Rickey (1965), Ralph Bunche (1971), and Mary Leakey (1996).

Here’s a lovely van Dyck:

Meanwhile in Dobrzyn, Hili’s dialogue is subject to interpretation (she’s not telling), but I’m pretty sure I know what it means.

Hili: Which invention was more important: a bed or a wheel? A: It depends on time of the day. Hili: I’m not sure. In Polish: Hili: Który wynalazek był ważniejszy – łóżko czy koło?
Ja: To zależy od pory dnia.
Hili: Nie jestem pewna.

Here is a tweet from Grania: Roy Moore accuses evolution of corrupting children.

Wanted to share a video of Roy Moore in 1997 arguing that kids commit drive-by shooting because they are taught evolution in school: "They're acting like animals because we've taught them they come from animals." pic.twitter.com/YoHZXKfpAl

— Christopher Massie (@chrismassie) December 7, 2017

Tweets from Matthew Cobb:

Red kites (Milvus milvus) in the snow (play video):

Red Kites in the snow today. Superb. pic.twitter.com/6WvsC6FYsw

— Drew Buckley (@drewbphoto) December 8, 2017

And the most perfect cat ball:

That's a 10/10 circle cat pic.twitter.com/iZP0jTctgp

— Luv Kittens Daily (@LuvKittensDaily) December 7, 2017

Another cat from reader Charleen:

When you know whats coming, but jump out of your skin anyway pic.twitter.com/RQiujmC7Df

— HUMOROUS ANIMALS (@CUTEFUNNYANIMAL) December 8, 2017

And a video of a kitten that appeared yesterday. LIVING THE DREAM!

Living the dream pic.twitter.com/01XthGvqIA

— Cute Emergency (@CuteEmergency) December 9, 2017


Categories: Science

Volumetric 3D printing promises nearly instant builds

Matter and energy from Science Daily Feed - Fri, 12/08/2017 - 2:18pm
By using laser-generated, hologram-like 3D images flashed into photosensitive resin, researchers have discovered they can build complex 3D parts in a fraction of the time of traditional layer-by-layer printing.
Categories: Science

Volumetric 3D printing promises nearly instant builds

Computers and Math from Science Daily Feed - Fri, 12/08/2017 - 2:18pm
By using laser-generated, hologram-like 3D images flashed into photosensitive resin, researchers have discovered they can build complex 3D parts in a fraction of the time of traditional layer-by-layer printing.
Categories: Science

Producing hydrogen from methane in a cleaner, cheaper way

Matter and energy from Science Daily Feed - Fri, 12/08/2017 - 2:17pm
A ceramic membrane makes it possible to produce compressed hydrogen from methane with near-zero energy loss.
Categories: Science

Producing hydrogen from methane in a cleaner, cheaper way

Computers and Math from Science Daily Feed - Fri, 12/08/2017 - 2:17pm
A ceramic membrane makes it possible to produce compressed hydrogen from methane with near-zero energy loss.
Categories: Science

Light from LIGO’s neutron star smashup just got even brighter

New Scientist Feed - Fri, 12/08/2017 - 1:43pm
The gravitational wave event from August still has surprises in store. Its light is three times brighter now, which may change how we think of gamma ray bursts
Categories: Science

I guess I just didn’t love my children enough

Pharyngula Feed - Fri, 12/08/2017 - 12:59pm

The callow young gentleman in the middle of this line of celebrities (I guess, I don’t know who any of them are) recently celebrated his 18th birthday.

His daddy gave him a nice present.

The party came to a total of about $4 million. And for his birthday gifts? The birthday boy received a full loaded blue Ferrari, an IWC Portugieser Tourbillion watch and a custom-made painting from Alec Monopoly.

Whoa. I betcha Donald Trump is giving the whole family a great big tax break, too.

Welcome to the world of wealth inequity!

Categories: Science

The Mueller Sanction

Why Evolution is True Feed - Fri, 12/08/2017 - 12:30pm

I don’t know who made this video, or how they got it to look so realistic, but it’s pretty cool. The Trump investigation as a James Bond story!

https://video.twimg.com/ext_tw_video/924111999306313729/pu/vid/1280x720/rzsxXzUZlwXav1RJ.mp4
Categories: Science

Revolutionizing electronics using Kirigami

Computers and Math from Science Daily Feed - Fri, 12/08/2017 - 12:23pm
A research team has developed an ultrastretchable bioprobe using a 'Kirigami' designs. The Kirigami-based bioprobe enables one to follow the shape of spherical and large deformable biological samples such as heart and brain tissues. In addition, its low strain-force characteristic reduces the force induced on organs, thereby enabling minimally invasive biological signal recording.
Categories: Science

Revolutionizing electronics using Kirigami

Matter and energy from Science Daily Feed - Fri, 12/08/2017 - 12:23pm
A research team has developed an ultrastretchable bioprobe using a 'Kirigami' designs. The Kirigami-based bioprobe enables one to follow the shape of spherical and large deformable biological samples such as heart and brain tissues. In addition, its low strain-force characteristic reduces the force induced on organs, thereby enabling minimally invasive biological signal recording.
Categories: Science

Scientists channel graphene to understand filtration, ion transport into cells

Matter and energy from Science Daily Feed - Fri, 12/08/2017 - 12:23pm
Nanometer-scale pores etched into layers of graphene can provide a simple model for the complex operation of ion channels, researchers have demonstrated.
Categories: Science

Too Big, Too Soon. Monster Black Hole Seen Shortly After the Big Bang

Universe Today Feed - Fri, 12/08/2017 - 12:10pm

It is a well known fact among astronomers and cosmologists that the farther into the Universe you look, the further back in time you are seeing. And the closer astronomers are able to see to the Big Bang, which took place 13.8 billion years ago, the more interesting the discoveries tend to become. It is these finds that teach us the most about the earliest periods of the Universe and its subsequent evolution.

For instance, scientists using the Wide-field Infrared Survey Explorer (WISE) and the Magellan Telescopes recently observed the earliest Supermassive Black Hole (SMBH) to date. According to the discovery team’s study, this black hole is roughly 800 million times the mass of our Sun and is located more than 13 billion light years from Earth. This makes it the most distant, and youngest, SMBH observed to date.

The study, titled “An 800-million-solar-mass black hole in a significantly neutral Universe at a redshift of 7.5“, recently appeared in the journal Nature. Led by Eduardo Bañados, a researcher from the Carnegie Institution for Science, the team included members from NASA’s Jet Propulsion Laboratory, the Max Planck Institute for Astronomy, the Kavli Institute for Astronomy and Astrophysics, the Las Cumbres Observatory, and multiple universities.

Artist’s impression of ULAS J1120+0641, a very distant quasar powered by a black hole with a mass two billion times that of the Sun. Credit: ESO/M. Kornmesser

As with other SMBHs, this particular discovery (designated ULAS J1120+0641) is a quasar, a class of super bright objects that consist of a black hole accreting matter at the center of a massive galaxy. The object was discovered during the course of a survey for distant objects, which combined infrared data from the WISE mission with ground-based surveys. The team then followed up with data from the Carnegie Observatory’s Magellan telescopes in Chile.

As with all distant cosmological objects, ULAS J1120+0641’s distance was determined by measuring its redshift. By measuring how much the wavelength of an object’s light is stretched by the expansion of the Universe before it reaches Earth, astronomers are able to determine how far it had to travel to get here. In this case, the quasar had a redshift of 7.54, which means that it took more than 13 billion years for its light to reach us.

As Xiaohui Fan of the University of Arizona’s Steward Observatory (and a co-author on the study) explained in a Carnegie press release:

“This great distance makes such objects extremely faint when viewed from Earth. Early quasars are also very rare on the sky. Only one quasar was known to exist at a redshift greater than seven before now, despite extensive searching.”

Given its age and mass, the discovery of this quasar was quite the surprise for the study team. As Daniel Stern, an astrophysicist at NASA’s Jet Propulsion Laboratory and a co-author on the study, indicated in a NASA press release, “This black hole grew far larger than we expected in only 690 million years after the Big Bang, which challenges our theories about how black holes form.”

This illustration shows the evolution of the Universe, from the Big Bang on the left, to modern times on the right. Image: NASA

Essentially, this quasar existed at a time when the Universe was just beginning to emerge from what cosmologists call the “Dark Ages”. During this period, which began roughly 380,000 years to 150 million years after the Big Bang, most of the photons in the Universe were interacting with electrons and protons. As a result, the radiation of this period is undetectable by our current instruments – hence the name.

The Universe remained in this state, without any luminous sources, until gravity condensed matter into the first stars and galaxies. This period is known as the “Reinozation Epoch”, which lasted from 150 million to 1 billion years after the Big Bang and was characterized by the first stars, galaxies and quasars forming. It is so-named because the energy released by these ancient galaxies caused the neutral hydrogen of the Universe to get excited and ionize.

Once the Universe became reionzed, photons could travel freely throughout space and the Universe officially became transparent to light. This is what makes the discovery of this quasar so interesting. As the team observed, much of the hydrogen surrounding it is neutral, which means it is not only the most distant quasar ever observed, but also the only example of a quasar that existed before the Universe became reionized.

In other words, ULAS J1120+0641 existed during a major transition period for the Universe, which happens to be one of the current frontiers of astrophysics. As if this wasn’t enough, the team was also confounded by the object’s mass. For a black hole to have become so massive during this early period of the Universe, there would have to be special conditions to allow for such rapid growth.

A billion years after the big bang, hydrogen atoms were mysteriously torn apart into a soup of ions. Credit: NASA/ESA/A. Felid (STScI)).

What these conditions are, however, remains a mystery. Whatever the case may be, this newly-found SMBH appears to be consuming matter at the center of a galaxy at an astounding rate. And while its discovery has raised many questions, it is anticipated that the deployment of future  telescopes will reveal more about this quasar and its cosmological period. As Stern said:

“With several next-generation, even-more-sensitive facilities currentlybeing built, we can expect many exciting discoveries in the very earlyuniverse in the coming years.”

These next-generation missions include the European Space Agency’s Euclid mission and NASA’s Wide-field Infrared Survey Telescope (WFIRST). Wheras Euclid will study objects located 10 billion years in the past in order to measure how dark energy influenced cosmic evolution, WFIRST will perform wide-field near-infrared surveys to measure the light coming from a billion galaxies.

Both missions are expected to reveal more objects like ULAS J1120+0641. At present, scientists predict that there are only 20 to 100 quasars as bright and as distant as ULAS J1120+0641 in the sky. As such, they were most pleased with this discovery, which is expected to provide us with fundamental information about the Universe when it was only 5% of its current age.

Further Reading: NASA, Carnegie Science, Nature

The post Too Big, Too Soon. Monster Black Hole Seen Shortly After the Big Bang appeared first on Universe Today.

Categories: Science

Three kinds of information from a single X-ray measurement

Matter and energy from Science Daily Feed - Fri, 12/08/2017 - 11:30am
The way in which electronic devices operate relies on the interaction between various materials. For this reason, researchers need to know exactly how specific chemical elements inside a computer chip or a transistor diode behave, and what happens when these elements bond. Physicists have now developed an innovative method that enables them to obtain several different types of information simultaneously from the interior of a nanoscale building block, and this while it is in the active state.
Categories: Science

Physicists excited by discovery of new form of matter, excitonium

Matter and energy from Science Daily Feed - Fri, 12/08/2017 - 11:30am
Excitonium has a team of researchers ... well... excited! They have demonstrated the existence of an enigmatic new form of matter, which has perplexed scientists since it was first theorized almost 50 years ago.
Categories: Science

Blackbody radiation from a warm object attracts polarizable objects

Matter and energy from Science Daily Feed - Fri, 12/08/2017 - 11:30am
You might think that a hot object pushes atoms and molecules away due to radiation pressure. But a research team showed that for a polarizable atom, the opposite occurs: the hot object attracts it. Using an atom interferometer, they found the attraction was 20 times stronger than the gravitational attraction between a tungsten object and a cesium atom. Though negligible in most situations, next-generation gravitational wave experiments may have to take this into account.
Categories: Science

Should a Christian baker be able to refuse to bake a cake for a gay wedding?

Why Evolution is True Feed - Fri, 12/08/2017 - 11:30am

In 2012, a Christian baker and self-proclaimed “cake artist” in Colorado, Jack Phillips, decided he wasn’t going to bake a wedding cake for a gay couple, Charlie Craig and David Mullins, because the request violated his religious beliefs. The couple sued for violation of the state’s anti-discrimination lawsuit, and won. The case was appealed, and now it’s been argued at the Supreme Court, as it has never been decided whether the Civil Rights Act of 1964, prohibiting discrimination on the basis of religion, color, sex, or national origin, also applies to sexual orientation. Phillips claims that, at least in this case, his First Amendment rights were being violated: that he should be able “to use his artistic talents to promote only messages that align with his religious beliefs.” The court will probably rule in a few months.

Remember, while it may be illegal to not make a cake requested by a gay customer or a Jewish customer, this case is about baking a wedding cake for a gay marriage, which could be construed as discrimination not against a person, but an act that violates the baker’s religion, so there are First Amendment considerations here.

Nevertheless, my own view is that the gay couple should prevail, for one could use one’s religion to discriminate against other things that seem wrong, like a Christian baker choosing not to make a Bar Mitzvah cake for a Jewish family, which comes close to discriminating against religion itself. (Remember, again, this is discrimination not against sexual orientation, but against an act that violates one’s religious beliefs.). Further, it gives weight to acts like Catholic doctors refusing to perform abortions when the pregnancy is due to rape or incest since such an act violates the doctor’s religion. While I believe that’s illegal in the U.S. (I’m not sure), but it’s still legal in Ireland, where abortion can be performed only to save the life of the mother. Given our new Supreme Court, all kinds of acts that seem discriminatory or dangerous could be approved because they privilege one’s religious belief over secular notions of equality. (I still, of course, believe that religious beliefs should be accommodated in public when they are not overly onerous to society.)

Andrew Sullivan is also conflicted (he’s a Catholic but also gay), but comes down on the side of the baker. In New York Magazine, he writes this:

Which is why I think it was a prudential mistake to sue the baker. Live and let live would have been a far better response. The baker’s religious convictions are not trivial or obviously in bad faith, which means to say he is not just suddenly citing them solely when it comes to catering to gays. His fundamentalism makes him refuse to make even Halloween cakes, for Pete’s sake. More to the point, he has said he would provide any form of custom-designed cakes for gay couples — a birthday cake, for example — except for one designed for a specific celebration that he has religious objections to. And those religious convictions cannot be dismissed as arbitrary (even if you find them absurd). Opposition to same-sex marriage has been an uncontested pillar of every major world religion for aeons.

And so, if there are alternative solutions, like finding another baker, why force the point? Why take up arms to coerce someone when you can easily let him be — and still celebrate your wedding? That is particularly the case when much of the argument for marriage equality was that it would not force anyone outside that marriage to approve or disapprove of it. One reason we won that debate is because many straight people simply said to themselves, “How does someone else’s marriage affect me?” and decided on those grounds to support or acquiesce to such a deep social change. It seems grotesquely disingenuous now for the marriage-equality movement to bait and switch on that core “live and let live” argument. And it seems deeply insensitive and intolerant to force the clear losers in a culture war into not just defeat but personal humiliation.

Nonetheless, here we are. And it is a hard case constitutionally. It pits religious and artistic freedom against civil equality and nondiscrimination. Anyone on either side who claims this is an easy call are fanatics of one kind or other. I’m deeply conflicted. I worry that a decision that endorses religious freedom could effectively nullify a large swathe of antidiscrimination legislation — and have a feeling that Scalia, for example, would have backed the gays in this case on those grounds alone. Equally, I worry that a ruling that backs the right of the state to coerce someone into doing something that violates their religious conscience will also have terrible consequences. A law that controls an individual’s conscience violates a core liberal idea. It smacks of authoritarianism and of a contempt for religious faith. It feels downright anti-American to me.

I sympathize with Sullivan, and feel a bit conflicted as well, as we have two “rights” competing with each other, but in the end I think the “freedom of speech” defense is weaker than the anti-discrimination principles that underlie our society.

The Supreme Court, which recently heard arguments on the case, seemed from their questions to be divided—largely along ideological lines. The case isn’t completely straightforward because baker considers himself an artist who can choose for whom to practice his art, and he has a First Amendment (constitutional) defense for his actions. Justice Anthony Kennedy may again be the swing vote.

So let’s take two polls here: one on how you feel and the other on how you think the Supreme Court (which has a conservative majority) will rule. As always, this is just my attempt to gauge opinion; I’m not pretending that this is a scientific result, or representative of anything beyond a sample of WEIT readers. And please take a few seconds to vote!

Take Our Poll (function(d,c,j){if(!d.getElementById(j)){var pd=d.createElement(c),s;pd.id=j;pd.src='https://s1.wp.com/wp-content/mu-plugins/shortcodes/js/polldaddy-shortcode.js';s=d.getElementsByTagName(c)[0];s.parentNode.insertBefore(pd,s);} else if(typeof jQuery !=='undefined')jQuery(d.body).trigger('pd-script-load');}(document,'script','pd-polldaddy-loader'));

and your prediction:

Take Our Poll (function(d,c,j){if(!d.getElementById(j)){var pd=d.createElement(c),s;pd.id=j;pd.src='https://s1.wp.com/wp-content/mu-plugins/shortcodes/js/polldaddy-shortcode.js';s=d.getElementsByTagName(c)[0];s.parentNode.insertBefore(pd,s);} else if(typeof jQuery !=='undefined')jQuery(d.body).trigger('pd-script-load');}(document,'script','pd-polldaddy-loader'));

 

h/t: Simon

 


Categories: Science

A terribly backwards take on the Franken resignation

Pharyngula Feed - Fri, 12/08/2017 - 11:28am

Ugh, New Yorker.

The case of Franken makes it all that much more clear that this conversation is, in fact, about sex, not about power, violence, or illegal acts. The accusations against him, which involve groping and forcible kissing, arguably fall into the emergent, undefined, and most likely undefinable category of “sexual misconduct.” Put more simply, Franken stands accused of acting repeatedly like a jerk, and he denies that he acted this way. The entire sequence of events, from the initial accusations to Franken’s resignation, is based on the premise that Americans, as a society, or at least half of a society, should be policing non-criminal behavior related to sex.

It’s not at all about sex. It’s about consent and respect. It’s about treating women as people.

If Al Franken had been participating in discreet wild orgies with consenting adult men and women, it would be fine — it would be none of our business, would have harmed no one, and would have been irrelevant to his position as a senator. I’m not interested in “policing non-criminal behavior related to sex” at all. The concern is the casual abuse of power, the expression of mocking contempt for a colleague, and the neglect of that all-important consent.

I don’t know why this is so hard to get across to some people. Your sexual behavior is personal and private, and as long as it only involves consenting adults, we shouldn’t care. It’s the Right that wants to bust into your bedroom and arrest you for your activities there.

Categories: Science

The Dorado Constellation

Universe Today Feed - Fri, 12/08/2017 - 11:00am

Welcome to another edition of Constellation Friday! Today, in honor of the late and great Tammy Plotner, we take a look at that fishiest of asterisms – the Dorado constellation. Enjoy!

In the 2nd century CE, Greek-Egyptian astronomer Claudius Ptolemaeus (aka. Ptolemy) compiled a list of all the then-known 48 constellations. This treatise, known as the Almagest, would be used by medieval European and Islamic scholars for over a thousand years to come, effectively becoming astrological and astronomical canon until the early Modern Age.

Since that time, many additional constellations have been discovered, such as Dorado. This southern constellation, which was discovered in the 16th century by Dutch navigators, is now one of the 88 constellations recognized by the International Astronomical Union (IAU). It is bordered by the constellations of Caelum, Horologium, Hydrus, Mensa, Pictor, Reticulum, and Volans.

Name and Meaning:

Because of its southerly position, Dorado was unknown to the ancient Greeks and Romans so no classical mythological connection exists. However, there are some very nice tales and history associated with this constellation. The name Dorado is Spanish for mahi-mahi, or the dolphin-fish. The mahi-mahi has a opalescent skin that turns blue and gold as the fish dies.

Image of the night sky taken at the European Southern Observatory’s Very Large Telescope in Chile. The Large and Small Magellanic Clouds are visible in the night sky. Credit: ESO, Y. Beletsky

This may very well be the reason Dorado is sometimes called the goldfish is certain stories and legends. Because the early Dutch explorers observed the mahi-mahi chasing swordfish, Dorado was added to their new sky charts following the constellation of the flying fish, Volans. Some very old star atlases refer to Dorado as Xiphias, another form of swordfish, but clearly its “fishy” nature stands!

History of Observation:

Dorado was one of twelve constellations named by Dutch astronomer Petrus Plancius, based on the observations of Dutch sailors that explored the southern hemisphere during the 16th century. It first appeared on a celestial globe published circa 1597-8 in Amsterdam. Dorado was taken a bit more seriously when it was included by Johann Bayer in 1603 in his star atlas, Uranometria, where it appeared under its current name.

It has endured to become one of the 88 modern constellations adopted and approved by the International Astronomical Union.

Notable Objects:

Covering 179 square degrees of sky, it consists of three main stars and contains 14 Bayer/Flamsteed designated stellar members. Dorado has several bright stars and contains no Messier objects. The brightest star in the constellation is Alpha Doradus, a binary star that is approximately 169 light years distant. This binary system is one of the brightest known, and is composed of a blue-white giant (classification A0III) and a blue-white subgiant (B9IV).

The Tarantula Nebula (NGC 2070) located in the southern Dorado constelaltion. Credit: ESO

Beta Doradus, the second brightest star in the constellation, is a Cepheid variable star located approximately 1,050 light years from Earth. Its spectral type varies from white (F-type) to yellow (G-type), like our Sun. Gamma Doradus is another variable, which serves as a prototype for stars known as Gamma Doradus variables, and is approximately 66.2 light years distant.

Another interesting character is HE 0437-5439, an unbound hypervelocity star in Dorado discovered in 2005. This star appears to be receding at the speed of 723 km/s (449 mi/s), and is therefore no longer gravitationally bound to the Milky Way. It is approximately 200,000 light years distant and is a main sequence star belonging to the spectral type BV (a white-blue subdwarf).

Most notable is the Large Magellanic Cloud (LMC), an irregular galaxy located in the constellations Dorado and Mensa. This satellite galaxy to the Milky Way is roughly 1/100 times as massive as our galaxy, with an estimated ten billion times the mass of the Sun. Located about 157,000 light years away, the LMC is home to several impressive objects – like the Tarantula Nebula and the Ghost Head Nebula.

There are no meteor showers associated with the constellation.

The Ghost Head Nebula (NGC 2080), . Credit: ESA/NASA/Mohammad Heydari-Malayeri

Finding Dorado:

The South Ecliptic Pole lies within Dorado and it is bordered by the constellations of Caelum, Horologium, Reticulum, Hydrus, Mensa, Volans and Pictor. It is visible at latitudes between +20° and -90° and is best seen at culmination during the month of January. Let’s begin our explorations with binoculars and Alpha Doradus – the “a” symbol on our map. One of the reasons this star shines so brightly is because it’s not one – but two.

Don’t get your telescope out just yet, because Alpha is separated by only only a couple tenths of a second of arc and both members are about a magnitude apart. Located about 175 light years away from our solar system, this tight pair averages a distance between each other that’s equal to about the same distance as Saturn from our Sun. That’s not particularly unusual for a binary star, but what is unusual is the primary star. Alpha Dor A’s spectrum is “peculiar” – very rich in silicon. It seems to be concentrated in a stellar magnetic spot!

Let’s have a look at Cephid variable star Beta Doradus – the “B” symbol on our map. Beta is an evolved super giant star and every 9.942 days it reaches a maximum brightness of magnitude 3.46 then drops to magnitude 4.08. While these types of changes are so slight they would be difficult to follow with just the eye, that doesn’t mean what happens isn’t important. By studying Cephids we understand “period-luminosity” relation. The pulsation period of a Cepheid gives us absolute brightness, and comparing it with apparent brightness gives us distance. That way, when we find a Cepheid variable star in another galaxy, we can tell just how far away that galaxy is!

Now, let’s go from one end of the constellation to the other with binoculars as we start with Delta Doradus – the “8” shape on our map. If you were on the Moon, this particular star would be the south “pole star” – just like Polaris is to the north on Earth! Sweep along the body of the fish and end at Gamma Doradus – the “Y” shape on our map. Guess what? Another variable star! But this one isn’t a Cepheid. Gamma Doradus variables are variable stars which display variations in luminosity due to non-radial pulsations of their surface.

The stars are typically young, early F or late A type main sequence stars, and typical brightness fluctuations are 0.1 magnitudes with periods on the order of one day. This is a relatively new class of variable stars, having been first characterised in the second half of the 1990s, and details on the underlying physical cause of the variations remains under investigation. We call these mysterious strangers Oscillating Blue Stragglers.

Don’t put away your binoculars yet. We have to look at R Doradus! Here we have a red giant Mira variable star that’s about 200 to 225 light years away from Earth. The visible magnitude of R Doradus varies between 4.8 and 6.6, which makes the variable changes easy to follow with binoculars, but when viewed in the infrared it is one of the brightest stars in the sky. However, this isn’t what the most interesting part is.

With the exception of our own Sun, R Doradus is currently believed to be the star with the largest apparent size as viewed from Earth. The stellar diameter of R Doradus could be as much as 585 million kilometers. That’s upwards to 400 times larger than Sol – yet it has about the same mass! If placed at the center of the Solar System, the orbit of Mars would be entirely contained within the star. Too cool…

Dorado contains a huge amount of deep sky objects very well suited for binoculars, small and large telescopes. So many, in fact, our small star chart would be so cluttered that it would be impossible to read designations. One of the most notable of all is the Large Magellanic Cloud, one of our Milky Way Galaxy’s neighbors and members of our local galaxy group. In itself, it is an irregular dwarf galaxy, distorted by tidal interaction with the Milky Way and may have once been barred spiral galaxies.

The Magellanic Clouds’ radial velocity and proper velocity were recently accurately measured by a team from the Harvard-Smithsonian Center for Astrophysics to produce a 3-D velocity measurement that clocked their passage through the Milky Way galaxy in excess of 480km/s (300 miles per second) using input from Hubble Telescope. This unusually high velocity seems to imply that they are in fact not bound to the Milky Way, and many of the presumed effects of the Magellanic Clouds have to be revised. Be sure to explore the LMC for its own host of nebula and star forming regions. It was host to a supernova (SN 1987A), the brightest observed in over three centuries!

For the telescope, there are many objects in Dorado that you don’t want to miss. (This article would be 10 pages long if I listed them all, so let’s just highlight a few.) For galaxy group fans, why not choose NGC 1566 (RA 04h 20m 00s Dec -56 56.3′) NGC 1566 is a spiral galaxy that dominates the Dorado Group and it is also a Seyfert galaxy as well. At the center of the cluster, look for interacting galaxies NGC 1549 and NGC 1553.

These two bright members are lenticular galaxy NGC 1553 (RA 04h 16m 10.5s Dec -55 46′ 49″), and elliptical galaxy NGC 1549 (RA 04h 15m 45.1s Dec -55 35′ 32″). Their interaction appears to be in the early stage and can be seen in optical wavelengths by faint but distinct irregular shells of emission and a curious jet on the northwest side. Chandra X-ray imaging of NGC 1553 show diffuse hot gas making up 70% of the emissions, dotted with many point-like sources (low-mass X-ray binaries) making up the rest.

Similar to Messier 60, these bright spots are binary star systems of black holes and neutron stars most of which are located in globular clusters and reflect this old galaxy’s very active past. In these systems, material pulled off a regular star is heated and gives off X-rays as it falls toward the accompanying black hole or neutron star.

The location of the southern Constellation Dorado. Credit: IAU/Sky&Telescope magazine

 

Turn your telescope towards NGC 2164 (RA 05h 58m 53s Dec -68 30.9′). Here we are resolving an open star cluster / globular cluster that’s in another galaxy, folks! Also nearby you’ll find faint open cluster NGC 2172 (RA 5 : 59.9 Dec -68 : 38) and galactic star cluster NGC 2159 (05 57.8, -68 38). What a treat to study in another galaxy!

Would you like to study another complex? Then let’s take a look at NGC 2032 (RA 05h 35m 21s Dec -67 34.1′). Better known as the “Seagull Nebula” this complex that contains four separate NGC designations: NGC 2029, NGC 2032, NGC 2035 and NGC 2040. Spanning across an open star cluster, there are many nebula types here including emission nebula, reflection nebula and HII regions. It is also bissected by a dark nebula, too!

Of course, no telescope trip through Dorado would be complete without stopping by NGC 2070 (RA 05h 38m 37s Dec -69 05.7′) – the “Tarantula Nebula”. Located about 180,000 light years from our solar system and first recorded by Nicolas Louis de Lacaille in 1751, this huge HII region is an extremely luminous object. Its luminosity is so bright that if it were as close to Earth as the Orion Nebula, the Tarantula Nebula would cast shadows. In fact, it is the most active starburst region known in our Local Group of galaxies! At its core lies the extremely compact cluster of stars that provides the energy to make the nebula visible. And we’re glad it does!

We have written many interesting articles about the constellation here at Universe Today. Here is What Are The Constellations?What Is The Zodiac?, and Zodiac Signs And Their Dates.

Be sure to check out The Messier Catalog while you’re at it!

For more information, check out the IAUs list of Constellations, and the Students for the Exploration and Development of Space page on Canes Venatici and Constellation Families.

Sources:

The post The Dorado Constellation appeared first on Universe Today.

Categories: Science

Record-breaking two-tonne fish is the heaviest of its kind

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