From white dwarves to dark matter: 75 years of discovery at McDonald Observatory

Editor’s Note: Today’s post comes to you from Rebecca Johnson, Editor of the StarDate Magazine at the McDonald Observatory.

A year-long celebration is underway to celebrate the 75th anniversary of the University of Texas at Austin’s McDonald Observatory, with the first event of 2014 being held at HMNS on Tues., Jan. 14 with a public lecture by Dr. Jon Winget.

McDonald Observatory 1

Photo credit: Sandia National Laboratories

Dubbed “impossible stars,” white dwarfs are the simplest stars with the simplest surface chemical compositions known — yet they are very mysterious. The McDonald Observatory leads in investigating white dwarfs along several avenues: telescope observations, theory, and most recently, the making of “star stuff,” using the most powerful X-ray source on Earth at Sandia National Laboratory.

Dr. Don Winget, one of the world’s leading experts on white dwarfs, will give a Distinguished Lecture at HMNS to examine the how studies of these stars can shed light on everything from the age of the universe to the understanding of dark matter and dark energy.

White dwarves are often difficult to locate due to the larger, brighter stars they are paired with

Located near Fort Davis, Texas, under the darkest night skies of any professional observatory in the continental United States, McDonald Observatory  hosts multiple telescopes undertaking a wide range of astronomical research. McDonald is home to the consortium-run Hobby-Eberly Telescope (HET), one of the world’s largest, which is being upgraded to begin the HET Dark Energy Experiment. An internationally known leader in astronomy education and outreach, McDonald Observatory is also pioneering the next generation of astronomical research as a founding partner of the Giant Magellan Telescope. The McDonald Observatory was dedicated May 5, 1939, and has supported some of the most important astronomical discoveries of recent decades about everything from extrasolar planets to exotic stars and black holes.

The Observatory plans a full year of activities around the state to celebrate. Events will run through August 2014, including a lecture series featuring McDonald Observatory astronomers in multiple cities and an Open House at the Observatory.

The celebration continues at the observatory’s website. Visitors to the anniversary pages can peruse a timeline of observatory history, watch several historical videos, and share their memories and photos of McDonald on an interactive blog called “Share Your Story.”

McDonald Observatory 2
(And while we’re at it, don’t forget about our own George Observatory‘s anniversary this year as well — 25 years of showcasing the night sky to the Greater Houston area!)

HMNS Distinguished Lecture
Date: Tues., Jan. 14, 6:30 p.m.
Topic: “Small Stars in a Large Context: All Things White Dwarf”
Speaker: Don Winget, Ph.D.
Where: HMNS Wortham Giant Screen Theater
How: Click here for advance tickets

Sponsored by the University of Texas at Austin’s McDonald Observatory in celebration of their 75th anniversary, with a pre-lecture reception at 5 p.m.


ANTS! [Cockrell Butterfly Center]

I would say that my feelings about ants are very mixed at the moment.

Feasting time (close in) Kentridge Park
Creative Commons License photo credit: williamcho

As an Entomologist, I’m absolutely fascinated by ants. Who wouldn’t be fascinated by these tiny insects that form amazingly complex and efficient societies that parallel those of humans?

Millions of Ants

We often think of ourselves as the most intelligent or civilized but I think ants can give us a run for our money! Their ability to cooperate with each other, to build nests, care for their young, exploit and manipulate resources of all kinds and defend themselves in many different ways have made them so successful that we often butt heads. We are struggling to keep the upper hand in agricultural and urban situations. They can be quite a nuisance, but one can’t help being intrigued!

Ants share the order Hymenoptera with bees and wasps, some of which also live in social groups. Ant colonies can range from a few dozen to millions of individuals, but unlike bees and wasps, there is no such thing as a solitary ant. Many form permanent nests while others are nomadic. Most are predators or scavengers, while some grow their own food. Some even farm and “milk” other insects like we do with cattle.

The Queen

Ant colonies typically consist of a queen (occasionally many), the only member of the colony to reproduce, and her sterile daughters or workers. Each year, new reproductive females and males, called drones, are produced. The winged males and females leave the colony to mate and start new colonies. The males die immediately after mating and the females shed their wings and become queens of their own colonies. Some colonies do not even have queens, only reproductive workers called gamergates. Some ant queens can live for up to 30 years, placing them high among the longest lived insects.

If the queen is the heart of the colony, the workers are the blood. She produces them, they develop into adults and they take care of every aspect of the colony. Their responsibilities range from tending to the queen, the young, the nest and each other, to foraging for food or building materials and protecting the nest. The younger ants can be founding tending to the inner workings of the nest while the older ones, who are more expendable, have the more hazardous task of foraging.

Worker Ants

Workers can be different sizes, but the largest are the soldiers (remember, all are female!). Soldiers are strong, brave, and often have sizable mandibles! Any worker ant will sacrifice itself for the good of the colony. Who do you think invented suicide missions? This selfless devotion and ability to work together as one unified organism is what has made them so successful. There are so many ants that they make up an estimated 20% of the terrestrial biomass on earth. That number far surpasses that of vertebrates!

We have several types of ants here at the Cockrell Butterfly Center, some captive, and some, well, not so captive. A facility such as ours is a haven for pest species including cockroaches, fruit flies, and lots and lots of ants. We’ve always had ants in the conservatory. The conditions are favorable and the food, including fallen butterflies, is plentiful. In the conservatory, they are manageable and they don’t really bother anyone.

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Creative Commons License photo credit: emills1
Can you see the queen leafcutter ant?
She’s so much bigger than the rest!

Of over 12,000 described species of ants, only about 20 species are considered “pests” – i.e., they mess with humans or our possessions in some way.  The pest species are mostly very small ants including sugar ants, ghost ants, pavement ants, and others, that sometimes get into our houses and larders.  Unfortunately one of our uninvited residents is  perhaps the hardest species of household pest ants to control, crazy ants.

Crazy Ants!

Ant Fight
Creative Commons License photo credit: zayzayem

Crazy ants, also known as longhorn crazy ants (Paratrechina longichornis) have earned their common name from their erratic and “crazy” movements. They move extremely quickly and in all different directions. They do not form foraging trails like most other ants, instead, they will go straight towards a food source, then meander all over the place back to their nest, making their actual nest very difficult to find!

Crazy ants feed on a wide variety of things including live or dead insects, fruits, nectar, honeydew (a secretion from hemipteran insects), and many household foods. The best way to control these ants is exclusion, or  keeping them out and keeping food and water sources out of the area.

Crazy ants are very easily identified. They are small, dark colored ants with very long antennae. They are monomorphic, meaning all of the workers look the same and are the same size. They do not sting but they can be present in such great numbers that they can be quite a nuisance. We’re currently doing everything we can to combat them!

New Leaf Cutter Ant Colonies!

Luckily, there are also ants that we are glad to have. After losing our tropical leaf cutter ant colonies in 2010, we have been blessed with 3 new colonies of Texas Leaf cutter ants (Atta texana).

I bet you didn’t know that leaf cutter ants are native to Texas! Leaf cutter ants are very fascinating and fun to watch! The workers use their powerful jaws to cut pieces of about 200 different types of leaves. They do not eat the leaves but carry them back to the nest. Once there, they chew them into a mulch that they use to grow a special type of fungus. The fungus is what the ant larvae feed on, so they are true fungus farmers!

Leaf cutter workers are polymorphic, meaning the workers differ in size and appearance. The smallest workers, called minims, are meant to tend to the fungus garden, queen, and brood. The minor workers, which are a bit bigger, patrol the nest and are the first line of defense. Mediae are larger workers with strong mandibles that forage, cut leaves and bring them back to the nest. The largest are the major workers. They act as the soldiers and are often very large with big strong mandibles that can break the skin. I know this from experience!

Leaf cutter ants also do not posses a stinger, but they sure do bite and will not let go! The mutualistic relationship between the ants and the fungus is quite incredible. The fungus must be actively maintained and cultivated by the ants. It constantly needs new fresh leaves to grow and survive. The ant larvae feed exclusively on the fungus and need it in order for them and the colony to survive. The ants constantly monitor the fungus to see if any leaves are toxic or if any other competing fungus is growing. They will destroy any other fungi with a bacterium that grows on their skin and secretes antimicrobial chemicals. WOW!

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Creative Commons License photo credit: emills1
A Mediae worker going after a leaf

Two of our new colonies came from the University of Texas, which was so generous to donate them to us! When we got them I noticed that the fungus gardens, which are usually green, were all white. These ants had been fed on oats instead of leaves, which they can apparently manipulate in the same manner. It’s really cool, they look like some formations you would find in a cave. One of these colonies will soon be on display for everyone to watch as they busily carry leaf fragments to their gardens.

There are so many interesting things about ants. They really are diverse and fascinating. I encourage you to read up on them a little bit; even just by clicking the links in this blog, you may find out things you would have never expected!

Next time you see ants trailing in your house or outdoors, don’t think of them as just a nuisance, think of how incredible they are and how hard they work. You may have a newfound respect for the little critters.

Until next time, happy bug watching!

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Creative Commons License photo credit: emills1
The white fungus garden

My love affair with the tropics (how and why I became a biologist)

 Our fearless leader
Dr. Larry Gilbert

My introduction to the tropics was in the summer of 1983, when I lucked into accompanying Dr. Larry Gilbert (UT Zoology) and his students on a field course to Corcovado National Park in Costa Rica.  Not being a student at the time (I’d gotten a BA in linguistics a couple years before but was working as a secretary on the UT campus), but having some proficiency in Spanish, I was hired by Dr. Gilbert as his assistant and translator since his regular teaching assistant was off making a film in New Guinea. 

After several weeks in Patterson Hall on the UT campus, translating documents and readying equipment, we left for Costa Rica, flying into the capitol, San Jose.  Here our party (5 graduate students plus Dr. Gilbert – Larry to his students – and myself) spent a couple of days at the “Costa Rica Inn” – a rambling one-story labyrinth of a hotel near the downtown area.  San Jose is a typical Central American city, with lots of traffic and pollution, no interesting architecture to speak of…but great ice cream and plenty of activity – and in those days, very safe at all hours.  We visited the Natural History Museum and the local university, picked up some supplies (foam mattresses and rum are what I remember!), and made our flight arrangements.  We were flying in to the park in two 5-seater Cessnas; there was no other access to the remote field site location. 

View of the Corcovado canopy from the plane.
Photo by Dr. Larry Gilbert.

The day arrived and we boarded the tiny planes.  I was quite nervous as I had never flown in such a small plane before, and the pilot warned us that it might be a bumpy ride due to rising air currents as we crossed the mountains.  And Larry joked about the two wrecked planes that decorated the end of the airstrip in the park… 

The flight took about an hour, and it was indeed turbulent.  Finally we flew out over the Osa Peninsula and saw nothing but forest below us, and then the Pacific Ocean beyond. We suddenly turned at right angles to the coastline to land at a tiny airstrip cleared in the rainforest, ending at the beach…and there, indeed, were the two wrecks.  Welcome to Sirena Station of Corcovado National Park!

We pitched tents in the clearing/horse pasture behind the rustic park station building; this would be our home for the next six weeks.  The students included Darlyne, studying heliconius butterflies; Kirk, studying the fish communities in freshwater streams; Jamie, studying howler monkeys, and Peggy and John, new students who had not yet decided on projects.  Two senior students, Peng Chai and Sue Boinski, were already in the park.  Peng was studying bird predation on butterflies.  “Bo” as she was called, was the equivalent of a mountain man, in my somewhat awed view.  She had spent the past several years following troupes of squirrel monkeys to learn about their behavior and mating habits, sometimes staying in the park for over a year at a stretch. In the course of her wanderings she had dodged fer-de-lance and bushmaster snakes, and had some (very shaky) video footage of a pair of jaguars lazily playing together, oblivious of their nervous human watcher. 

Fruits of the
Corcovado rainforest.
Photo by Dr. Larry Gilbert.

The Sirena station was a bustling place.  Since in those days (before the gold miner crisis of 1985) it served as the park headquarters, it was the central point in Corcovado for communications and supplies, which were all brought in by plane.  The park director was stationed here, along with about 5-6 park guards.  Other park guards travelling by horseback from the outlying stations came in to pick up their allotment of supplies, or to rotate out for a week’s holiday.  The radio crackled all day long:  “Sierra Papa Norte Dos a Sierra Papa Norte” (National Park Service station 2 to headquarters).  I learned all sorts of things in radio lingo – “Cambio” meant over, “Dos” meant good, “Dos y medio” was so-so, “Tres” meant bad, “un 22” was a telephone call, “10” was crazy, etc. 

The station in those days was rustic.  Electricity was provided by generator only at lunchtime and for a couple hours in the evening.  Running water was ingeniously piped in from a nearby stream.  Course participants and park guards all ate together in a little open-sided building:  generous portions of rice and beans, smaller portions of meat and vegetables, inventive desserts, and drinks made from fresh tropical fruits, all deliciously prepared by Maria, the feisty and attractive cook.

Buttress of a tropical giant.
Photo by Dr. Larry Gilbert.

The first few days Larry led his students and me on long, sometimes wild walks through the forest – up over the steep knife-edged ridges, crashing down through stream beds, slogging along the beach or sweltering through open areas.  What an amazing place!  I was in love with the forest from the moment I saw it.  So many plants – so many insects, birds, monkeys, frogs, snakes, etc.  But especially plants.  It was like being in the most amazing botanical garden.  Here things I’d only seen as houseplants grew rampantly everywhere.  Ferns were not just ferns but trees.  And trees, with their huge buttresses as big around as a house, towered into the canopy.

Squirrel Monkies are common
near Sirena

After a week or so of our introductory walks, the students settled down to their research projects.  Since I wasn’t a student and didn’t have my own project, I helped some of the others where I could.  I soon was spending most of my time with Kirk, helping him census the fish in the many small streams that cut across the peninsula – streams so clear and clean that we drank out of them.  I learned a lot about fish that summer!  At night, we all sat in the little screened porch behind the radio room, burning candles and mosquito coils while we read or wrote up our field notes, or listened to one of the students give a status report on his or her project.  Larry often regaled us with funny stories of his past students…considerably embellished over the years, I am sure!

 Tropical leaf-footed bug

All too soon the summer came to an end, and we had to leave the park and head back to Texas to begin the new semester.  We packed the tents and our supplies into coolers to keep out the mildew.  Said our goodbyes to the park guards and to Maria.  Cleaned up the area we had taken over as our evening “lab.”  While we waited for the planes to arrive I took a last walk up the Claro trail to a ridge where, sitting on the buttress root of a huge strangler fig, I could see over the forest and out to sea.  What an adventure it had been!  What a lot of amazing biology I had learned!  Nostalgia for the place swept over me – but I heard the drone of the plane and had to rush back to camp.  We boarded the Cessna, and as it rumbled down the bumpy airstrip and began to lift into the air, I thought – if the plane crashes on the way back, I will die happy.  I have just spent the most amazing summer of my life.

I ended up becoming one of Larry’s students and spending several more summers in the park and elsewhere in the tropics.  However, that first experience stays with me as one of the real highlights of my existence on this earth. 

 Ornate flower of a tropical passionvine
 Red-eyed treefrogs.

Science Doesn’t Sleep (7.16.08)

Now all he needs is 20 years or martial arts
training and a lair.
Creative Commons License
photo credit: Beard Papa

So here’s what went down after you logged off.

He’s the only superhero without any real superhuman powers – unless extreme bitterness counts. So – is a real Batman scientifically possible?

Tomorrow, Texas’ Public Utility Commission will decide which of several wind energy proposals to adopt. More on the plans they’re evaluating here.

The Brooklyn Museum is in the process of putting their entire collection online – complete with photos, descriptive information and where the object can be found in the physical museum. You can check out a preview of this very cool new feature here.

Nanoparts are really small (hence the name) and it takes a really long time to build something that’s even visible out of them – much less an organ. Now, researchers at MIT and Harvard are working to find a way for nanoparts to self assemble – which would make the process of fabricating different types of organs much quicker.

Researchers at the University of Texas may have found the Achilles Heel of the HIV virus – an antibody that disables the virus’ ability to infect cells.

Just like humans, sick bees are much less productive at work.