Monday, May 9, 2016

Ida, Sweet as Apple Cider

During one of our recent walks around the neighborhood, a nice old man stopped Ida and I for a chat. When I mentioned her name, he instantly started singing a lovely melody "Ida, sweet as apple cider..." which I had never heard before.  I asked him about it and he claimed it was just one of those old-timey songs he liked, "you know, one that a barbershop quartet would sing!"

So of course I looked it up when we returned home and learned it immediately.  She even dances when I play it for her :) Music time is my favourite part of our days!

Tuesday, April 19, 2016

Introducing Ida Luna

While this blog has been quiet over the last few months, my home certainly hasn't been, thanks to welcoming to the world my little girl: Ida Luna! 

She was born in February 2016, and started with a healthy amount of skepticism :)  here she is with her grandma on day 2: 

I'm not sure about this world, grandma, but i sure like your singing!
and a few weeks later, she's still got it!


she's a content little baby and we're enjoying this new life together.


this is our major mode of transportation.  both of us LOVE the Yoli & Otis carrier! 


her expressions are endlessly cute and varied!


to be honest, i'm really enjoying time off work.  i'm doing some fun side projects (stay tuned!) that are keeping my mind entertained, but overall, it's a nice break from the pressures of academia and media. 

Mama and Ida Luna at 7 weeks

Thursday, February 11, 2016

the gravity of new life

the rumour is that the LIGO project has detected a significant signal of gravitational waves originating from two distant black holes orbiting each other and merging together!

a big press release from the Laser Interferometer Gravitational-wave Observatory (LIGO) is scheduled for tomorrow (Thursday, Feb. 11, 2016 10:30 AM US EST).  you can WATCH the news of the project update HERE.

so what are gravitational waves?  PhD Comics explains them very well in this video:



and if you're curious about how we detect these amazingly weak gravitational waves?  check out this post by Markus Pössel.


in other major life events... i'm 40 weeks along and ready to meet my tiny baby ANY TIME NOW!  very exciting :)


Monday, January 25, 2016

Five things we know about the universe that will make you feel very small

Here is an article I contributed to ABC Science, originally posted here.


Five things we know about the universe that will make you feel very small.

One thing we know about the universe is that it's really big. Another is that thinking about it and trying to understand it will make your brain hurt.

Astronomer Amanda Bauer takes us through her top five mind-expanding things we know (or don't know) about the universe.

1. There is no edge of the universe
PHOTO: Full-sky map of the oldest light in the universe (NASA/WMAP Science Team)
There is one edge we know of - our horizon, which is the limit of how far we can see.

Imagine sailing on a boat on the ocean and seeing a horizon in the distance, past which you know there is more Earth, but you just can't see it. We've measured the universe to be flat (as opposed to curved like Earth or saddle-shaped), but our horizon exists because of the finite speed of light.

Beyond that visible horizon, we think the universe just keeps going in the same way - forever.

We have no reason to believe there is an edge. But we also have no way of measuring this infinity because we physically cannot see it.


2. Dark matter and dark energy make up 95 per cent of the universe

PHOTO: A composite image showing the galaxy cluster 1E 0657-56, better known as the bullet cluster. Gravitational lensing was used to locate the dark matter (shown as blue patches) in these two colliding galaxies. The pink colour shows gas blown apart by the collision. (NASA/Chandra X-Ray Observatory)

Only 5 per cent of the universe is made of ordinary material like planets, stars, cars, and coffee. This "normal matter" is made mostly of protons, neutrons, and electrons.

Another 24 per cent is an exotic material that interacts through gravity, but produces no light, making it invisible to us. We call this "dark matter".

While dark matter only interacts with normal matter very weakly, particle physicists have plausible candidates for what dark matter is.

Hopefully particle accelerators like the Large Hadron Collider will provide more insight for scientists very soon.

That brings us to the final 71 per cent of the stuff in the universe, which is a truly bizarre type of matter. Perhaps it's not matter at all, but a property of the universe itself. We call this mysterious stuff "dark energy".

What we do know is that dark energy has a gravitationally repulsive effect that is causing the expansion of the universe to speed up. But we don't understand how this acceleration is happening.


3. There is no centre of the universe

PHOTO: In a way, we're all at the centre of our own universe. (NASA/Ames/JPL-Caltech)
The universe has been expanding ever since the Big Bang 13.8 billion years ago.

But the Big Bang should not be imagined as a normal explosion in space. Rather, the Big Bang is an explosion of space itself, so that every point in space expands equally away from every other point in space. There is no centre to the expansion.

From our galaxy we measure that all galaxies are moving away from us, and the farther the galaxy, the faster away it is moving.

The interesting thing is that if you zoomed off to any other galaxy in the universe, you would measure the exact same effect - all other galaxies would be moving away from you.

In this way, you could argue that you are the centre of the universe. But then, so is everyone else.


4. Far-away galaxies offer a glimpse into the past

PHOTO: At 3 million light years from Earth, the Triangulum galaxy is even further away than Andromeda, so gives us a glimpse even further back in time. (NASA)
When we look at distant galaxies, we are actually looking at a snapshot of the past.

Some galaxies are located so far away their light takes billions of years to reach us, even travelling at the speed of light. The images we collect through our telescopes tell us what the galaxies looked like billions of years ago, when the light left the galaxy.

Andromeda is the nearest spiral galaxy to our Milky Way. It floats at a distance of 2.5 million light-years, so the views we capture of Andromeda show us what it looked liked 2.5 million years ago. And that's the closest spiral galaxy.

The farthest galaxy we have detected is 13 billion light years away. This means we are looking at galaxy light as it was only 2 billion years after the Big Bang.

We will never capture light from the future though, only the distant past.


5. The future will be dominated by black holes

PHOTO: Pretty much all galaxies have a supermassive black hole at their centre. This one, a spiral galaxy known as NGC 4258, also has two unusual spiral arms that glow in X-ray, shown in purple. (ASA/CXC/JPL-Caltech/STScI/NSF/NRAO/VLA)
We are currently in the Stelliferous Era - meaning the universe has a lot of stars. This era began a few hundred million years after the Big Bang when the very first stars formed.

Now, almost 13.7 billion years later, new stars continue to form, although the number of new stars forming each year is dropping.

Eventually, new stars will stop forming and all stars will slowly burn out. But in that very distant future, supermassive black holes will still thrive.

It's believed that nearly every galaxy in the universe has a supermassive black hole at its centre, which means that eventually hundreds of billions of supermassive black holes will be spread throughout our ever-expanding universe.

Over trillions and trillions and trillions, and many more trillions, of years these black holes will slowly evaporate through Hawking Radiation.

The leftover elementary particles will be left to zoom through a vast, cold space with nothing much around to bump into.

Sounds very empty.

Monday, January 18, 2016

in conversation with neil degrasse tyson

here are some video highlights from neil degrasse tyson's tour around australia last year.

i hosted the melbourne and brisbane shows while the sydney and canberra stops were hosted by derek muller (veritasium).



and a few of my favourite photos from the events:

Tamara Davis, Neil deGrasse Tyson, and me in Brisbane

sharing a pre-show moment during sound check




Sunday, January 17, 2016

All 5 bright planets up in the morning sky!

all of you early risers may have noticed the lovely line of bright planets across the sky in the morning hours before sunrise lately.  definitely get out and have a look between jan 20th and feb 20th for a spectacular view, no matter where on earth you live!


you'll need to be able to see low on the horizon to spot mercury until early february or so, but you can do it if you have an unobstructed view!

this alignment of the planets has not occurred for over ten years. it's rare because all the planets have to be on the same side of the sun in their orbits.  while venus, mars, jupiter, and saturn have been in the morning sky all year, mercury is just getting ready to transition from being visible in our evening sky to being visible in the morning sky.  hopefully the visualisation below makes that clear.

via The Conversation
so... get out early and LOOK UP! 

Thursday, December 31, 2015

natural woman

the one, the only, ARETHA FRANKLIN!   this brought me to tears - so pure, so passionate, so powerful.  a great way to say goodbye to 2015.

Friday, December 25, 2015

special full moon on christmas day

today's full moon is the first on christmas day in 38 years.  the year was 1977 - when Star Wars Episode IV was released!

via NASA

without any spoilers - i really enjoyed the new star wars, the force awakens, released this holiday season.  i enjoyed most of the new characters they introduced, including Rey, who is a major character.  but how pathetic that she's not included by several retailers?   DO BETTER HUMANS!

From Jamie Ford on twitter

anyway, happy holidays, everyone!

Sunday, November 29, 2015

Cloudy with a chance of life: how to find alien life on distant exoplanets

This article was originally published in The Conversation on on 26th November 2015.


Cloudy with a chance of life: 

by Brad Carter, Amanda Bauer, & Jonti Horner

How do you go about hunting for life on another planet elsewhere in our galaxy? A useful starting point is to imagine looking from afar for signs of life on Earth. In a telescope like those we have on Earth, those aliens would likely just see the Earth and sun merged together into a single pale yellow dot.

If they were able to separate the Earth from the sun, they’d still only see a pale blue dot. There would be no way for them to image our planet’s surface and see life roving upon it.

However, those aliens could use spectroscopy, taking Earth’s light and breaking it into its component colours, to figure out what gases make up our atmosphere. Among these gases, they might hope to find a “biomarker”, something unusual and unexpected that could only be explained by the presence of life.

On Earth, the most obvious clue to the presence of life is the abundance of free oxygen in our atmosphere. Why oxygen? Because it is highly reactive and readily combines with other molecules on Earth’s surface and in our oceans. Without the constant resupply coming from life, the free oxygen in the atmosphere would largely disappear.

Biomarkers

But the story isn’t quite that simple. Life has existed on Earth for at least 3.5 billion years. For much of that time, however, oxygen levels were far lower than those seen today.

And oxygen alone is not enough to indicate life; there are many abiological processes that can contribute oxygen to a planet’s atmosphere.

The concentration of oxygen in the Earth’s atmosphere over the last billion years. As a reference, the dashed red line shows the present concentration of 21%.  Wikimedia

For example, ultraviolet light could produce abundant oxygen in the atmosphere of a world covered with water, even if it was devoid of life.

The upshot of this is that a single gas does not a biomarker make. Instead, we must instead look for evidence of a chemical imbalance in a planet’s atmosphere, something that can not be explained by anything other than the presence of life.

Here on Earth, we have one: our atmosphere is not just rich in oxygen, but also contains significant traces of methane. While abundant oxygen or methane could easily be explained on a planet without life, we also know that methane and oxygen react with each other strongly and rapidly.

When you put them together, that reaction will cleanse the atmosphere of whichever is least common. So to maintain the amount of methane in our oxygen-rich atmosphere, you need a huge source of methane, replenishing it against oxygen’s depleting influence. The most likely explanation is life.

Observing exoplanetary atmospheres

If we find an exoplanet sufficiently similar to our own, there are several ways in which we could study its atmosphere to search for biomarkers.

When a planet passes directly between us and its host star, a small fraction of the star’s light will pass through the planet’s atmosphere on its way to Earth. If we could zoom in far enough, we would actually see the planet’s atmosphere as a translucent ring surrounding the dark spot that marks the body of the planet.

How much starlight passes through that ring gives us an indication of the atmosphere’s density and composition. What we get is a “transmission spectrum”, which is an absorption spectrum of the planetary atmosphere, illuminated by the background light of the star.

Our technology has only now become capable of collecting and analysing these spectra for the first time. As a result, our interpretation remains strongly limited by our telescopic capabilities and our burgeoning understanding of planetary atmospheres.

Despite the current challenges, the technique continues to develop with great success. In the past few years, astronomers have discovered a wide variety of different chemical species in the atmospheres of some of the biggest and baddest of the known transiting exoplanets.

Many exoplanets may have no atmosphere at all. NASA/JPL-Caltech

Eclipses

Another approach involves observing a transiting planet and its star as they orbit one another. The goal here is to collect some observations when the planet is visible (but not in transit), and others when it is eclipsed by its star.

With some effort, astronomers can subtract one observation from the other, effectively cancelling the hugely dominant contribution of light from the star. Once that light is removed, what we have left is the day-side spectrum of the planet.

[Star + Planet] - [Star] = [Planet] NASA/JPL-Caltech/R. Hurt (SSC/Caltech)

The future

Astronomers are constantly developing new techniques to glean information about exoplanetary atmospheres. One that shows particular potential, especially for the search for planets like our own, is the use of polarised light.

Most of the light we receive from planets is reflected, originating with the host star. The process of reflection brings with it a subtle benefit - the reflected light gains a degree of polarisation. Different surfaces yield different levels of polarisation, and that polarisation might just hold the key to finding the first oceans beyond the solar system.

By rotating a polarising filter, we can block light of certain polarisation. This is how polarised sunglasses cut the glare from puddles and the ocean on a sunny day.  Wikimedia, CC BY-SA

These methods are still severely constrained by two factors: the relative faintness of the exoplanets, and their proximity to their host star. The ongoing story of exoplanetary science is therefore heavily focused on overcoming these observational challenges.

Further down the line, advances in technology and the next generation of telescopes may allow the light from an Earth-like planet to be seen directly. At that point, the task becomes (slightly) easier, in part because the planet can be observed for far longer, rather than just relying on eclipse/transit observations.

But even then, spectroscopy will be the way to go; the planets will still be just pale blue dots.

What we have seen so far

The exoplanets we have discovered to date are highly inhospitable to life as we know it. None of the planets studied so far would even be habitable to the most extreme of extremophiles.

The planets whose atmospheres we have studied are primarily “hot Jupiters”, giant planets orbiting perilously close to their host stars. As they skim their host’s surface, they whizz around with periods of just a few days, yielding transits and eclipses with every orbit.

Because of the vast amounts of energy they receive from their hosts, many of these “hot Jupiters” are enormous, inflated far beyond the scale of our solar system’s largest planet. That size, that heat and their speed, make them the easiest targets for our observations.

But as our technology has improved, it has also become possible to observe, through painstaking effort, some smaller planets, known as “super-Earths”.

Atmospheres of distant planets…

The hot Jupiter HD189733 has one of the best understood planetary atmospheres beyond the solar system.

Artists impression of the broiling blue marble, HD 189733 b. NASA, ESA, M. Kornmesser

Observations by the Hubble Space Telescope, in 2013, suggest a deep-blue world, with a thick atmosphere of silicate vapour. Other studies have shown its atmosphere to contain significant amounts of water vapour, and carbon dioxide.

Overall, however, it appears to be a hydrogen-rich gas giant like Jupiter, albeit super-heated, with cloud tops exceeding 1,000 degrees. Beneath the cloud turps lies a widespread dust layer, featuring silicate and metallic salt compounds.

The young giant planets in the HR8799 system appear to have hydrogen-rich but complex atmospheres, with compounds such as methane, carbon monoxide and water. They are likely larger, younger, and hotter versions of our own giant planets - with their own unique subtleties.

A direct image of the four planets known to orbit the star HR 8799. Ben Zuckerman

For the super-Earth GJ1214b the lesson is to be careful about making conclusions. Early suggestions that this might be a “water world” or have a cloudless hydrogen atmosphere have since been superseded by models featuring a haze of hydrocarbon compounds (like on Titan), or grains of potassium salt or zinc sulphide.

While the search for Earth-like planets continues using ground- and space-based telescopes, exoplanetary scientists are eagerly awaiting the launch of the James Webb Space Telescope JWST.

That immense telescope, scheduled for launch in around October 2018, could mark the true beginning of the exciting search for distant atmospheric biomarkers and exoplanetary life.