Newsflash: Earth Not 6000 Years Old!

This may come as a bit of a surprise to the Young Earth Creationists out there, but we have a pretty good handle on the age of the universe, and it's not 6,000 years old. Nope. It's 13.73 billion years old, give or take 120 million years.

It's the 120 million number that amazes me - we know the age of the universe to fantastic accuracy. What's more, we also know the age of the Universe when recombination occurred to within 3,100 years ( Recombination happened when electrons were first able to be captured by protons, forming neutral hydrogen for the first time after the big bang) just 375,938 years after the big bang.

How do we know this much cool stuff? It's all in the five year report of NASA’s Wilkinson Microwave Anisotropy Probe (WMAP), measuring the Cosmic Microwave Background - the photons that are left over from the big bang. Phil Plait has an excellent overview of the process:

It’s those photons WMAP sees. After 13.7 billion years, the expansion of the Universe has cooled the light, stretched its wavelength from ultraviolet to microwave. Another way to think about it is that the temperature associated with each photon went from thousands of Kelvins down to just a few, less than 3, in fact. That’s -270 Celsius, and -454 Fahrenheit.

That light emitted just after recombination tells us a vast amount about the Universe at that time. By carefully mapping the exact wavelength of the light and the direction from where it came, we can tell the density and temperature of the matter at that time. Incredibly we can also tell how much dark energy there was, and even the geometry of the Universe: whether it is flat, open, or closed.

Truly incredible. The important thing is that these results agree with the theory to an amazing degree - we can have high confidence that our theories of the beginning of the universe are not too far off the mark. That's what science is all about - generating testable theories that are either supported or knocked down by direct observational evidence. It's a process that has brought us incredibly far in our understanding of nature, and continues to build our knowledge.

Testable: what science is, and what religion isn't.

Avalanche on Mars!

This is just an incredible picture. the HiRISE camera on Mars Reconnaissance Orbiter took a picture of an avalanche in progress. Here's the shot:


The Bad Astronomer has more info on an amazing piece of luck.

Mapping light pollution

An astronomy post, for a change!

A majority of people now live in cities, so they have not seen all the wonders of the night sky from a truly dark environment. I live in the middle of nowhere, so it's less of a problem here, but there's still pollution from nearby streetlights and the town.

Well, now there's an effort underway to quantify how much light pollution is affecting stargazers around the world. The GLOBE project is asking for your help. It's pretty straightforward:

1) Find your latitude and longitude.

2) Find Orion by going outside an hour after sunset
(about 7-10pm local time).


3) Match your nighttime sky to one of their magnitude charts.

4) Report your observation.

5) Compare your observation to thousands around the world.

GLOBE will then be able to compare pollution levels to last year, when they had 8491 observations. They're hoping for more this year. It's a great excuse for you to go out and look at the stars - and, if you can, encourage others to do the same, especially kids. Generating an interest in Astronomy now will pay off down the road with more educated people in all aspects of science.

So, go out and enjoy the sky. They're accepting observations from now until March 8th.

Happy Sputnik Day

On October 4th, 1957, Sputnik launched the space age.

It was a tiny probe, but had a huge impact. Just 12 short years afterwards, there would be a man on the moon. It's amazing to think about. In future centuries, it will be one of the watershed moments in human history. The Bad Astronomer has a nice write up about it.

A real shooting star

This image from Nasa is amazing. It shows Mira, a star in the constellation Cetus. Turns out that Mira is a giant red star, and has been periodically shedding it's atmosphere as it moves along the main sequence to becoming a white dwarf, a path that our Sun will eventually take. What's cool about this though is that Mira has and extremely high speed relative to the interstellar medium - about 130 kilometers per second (about 80 miles per second). In the Interstellar medium is gas and dust, basically a thin fog floating among the stars. As Mira moves through this fog, the gas it is shedding blown backwards, leaving a long tail behind it, and resulting in the image you see below:


Now, you can't see this in visible light, but the these images were taken in the ultraviolet, which means the gas is emitting UV radiation. The images were taken by the Galaxy Explorer (GalEx) mission. You can see the differences in the image below (top is UV, bottom is visible, where Mira looks like a regular star.

This is why astronomy is so cool!

More GalaxyZoo!

The folks at Galaxy Zoo (see my previous post) sent out an update today on their progress so far:

To date, unbelievably, 80,000 of you have viewed and classified more than 10 million images of galaxies. Our initial target of having each galaxy (there are
a million in our initial sample from the Sloan Digital Sky Survey) viewed once is more than done, but we still need your help. Our NEW target is to have each and every galaxy classified by 20 separate users.

Obviously, with more people looking at a galaxy, the better statistics they get on the classification. It won't be too long, I think, before they achieve their goal. In the meantime, here are a couple more cool images of galaxies I've been assigned to analyze in the last few weeks:

Galaxy Zoo!

Today's astronomical telescopes of all kinds, ground and space based, take millions of pictures of the distant reaches of the Universe. All that data takes some analyzing, so a group of scientists working with the Sloan Digital Sky Survey (SDSS) have turned to the public for help. Galaxy Zoo gets amateurs involved in classifying galaxies as spirals or ellipticals. These are images that maybe no-one has ever seen before, tucked away in dusty corners of digital images. It's important work because:

...visitors will help astronomers to understand the structure of the universe. The new digital images were taken using the robotic Sloan Digital Sky Survey telescope in New Mexico.

‘It’s not just for fun’ said Kevin Schawinski of Astrophysics at Oxford University where the data will be analysed. ‘The human brain is actually better than a computer at pattern recognition tasks like this. Whether you spend five minutes, fifteen minutes or five hours using the site your contribution will be invaluable.’ Visitors will be able to print out posters of the galaxies they have explored and even compete to see who’s the best virtual astronomer.

I signed up (it's a fairly easy process), and I've already found a couple of interesting objects:

One word of warning though.....it's addictive!

Don't miss Saturn and Venus!

Tonight and tomorrow night, June 30th and July 1st, Saturn and
Venus will share the same patch of sky.
If you have a telescope or binoculars, with a magnification of 50x or less you;ll be able to see Venus' crescent and Saturn's rings in the same field of view. It should be spectacular! Don't miss it!

M81 writ large

The sharpest ever image of the spiral galaxy M81 was released yesterday at the American Astronomical Society Meeting in Honolulu.
The galaxy is 11.6 million light years distant (practically next door!), yet the image can resolve individual stars. The Hubble data was taken with the Advanced Camera for Surveys in 2004 through 2006. You can download the high resolution image here, although be warned, it is 690MB (yes, 690!!) in size, and full resolution is 22620 X 15200 pixels. What's really cool is picking an area and zooming in to see the individual stars (assuming your computer can handle the image).

Dark Matter: It exists!

A remarkable new image was revealed yesterday that constitutes strong new evidence for dark matter:


Dark matter is matter which makes up the bulk of the mass of the universe, but which has escaped detection by conventional means. It's required because observations of things like the rotational speeds of galaxies and orbital velocities of galaxies in clusters, Gravitational lensing of background objects by galaxy clusters and the temperature distribution of hot gas in galaxies and clusters of galaxies don't make sense unless there is additional, undetected mass. Dark matter also plays a central role in galaxy evolution and has measurable effects on the anisotropy of the cosmic microwave background. All these lines of evidence suggest that galaxies, clusters of galaxies, and the universe as a whole contain far more matter than that which interacts with electromagnetic radiation.

Unfortunately, because it doesn't interact with electromagnetic radiation, it's hard for us to see directly - we can only infer its presence via gravitational effects. That's what the new study, to be published in Astrophysics Journal, has done.

Astronomers using NASA's Hubble Space Telescope have discovered a ghostly ring of dark matter that formed long ago during a titanic collision between two massive galaxy clusters. The ring's discovery is among the strongest evidence yet that dark matter exists. Astronomers have long suspected the existence of the invisible substance as the source of additional gravity that holds together galaxy clusters. Such clusters would fly apart if they relied only on the gravity from their visible stars. Although astronomers don't know what dark matter is made of, they hypothesize that it is a type of elementary particle that pervades the universe.

This Hubble composite image shows the ring of dark matter in the galaxy cluster Cl 0024+17. The ring-like structure is evident in the blue map of the cluster's dark matter distribution. The map was derived from Hubble observations of how the gravity of the cluster Cl 0024+17 distorts the light of more distant galaxies, an optical illusion called gravitational lensing. Although astronomers cannot see dark matter, they can infer its existence by mapping the distorted shapes of the background galaxies. The map is superimposed on a Hubble Advanced Camera for Surveys image of the cluster taken in November 2004.

This ring will prove important to astronomers for many reasons. This is the first time a dark matter halo has been discovered that's different in shape from the other mass in a cluster, and it will allow researchers to make better predictions of how dark matter behaves, and how it can be shaped by normal matter. Plus, the image is just way cool!

Most Massive Supernova

The brightest supernova ever recorded may in fact be a new kind of supernova, according to researchers using the Chandra X-ray Observatory. The supernova is so bright, researchers are having to revise their ideas of what happens when supermassive stars (100-150 sun masses) explode. SN2006gy is 240 million light years distant in the galaxy NGC 1260, and it shone brighter than the galactic center:

Previously, it was thought that these types of supernovas usually occur when massive stars exhaust their fuel and collapse under their own gravity, forming a black hole. In these cases, much of the mass of the star doesn't explode, but is captured by the black hole.

It's postulated that in the case of SN2006gy however, that the core of a the massive star produced so much gamma ray radiation that some of the energy from the radiation converted into particle and anti-particle pairs. The resulting drop in energy caused the star to collapse under its own huge gravity.

After this violent collapse, runaway thermonuclear reactions ensue and the star explodes, spewing the remains into space. The SN2006gy data suggest that spectacular supernovas from the first stars - rather than completely collapsing to a black hole as theorized - may be more common than previously believed.

"Of all exploding stars ever observed, this was the king," said Alex Filippenko, leader of the ground-based observations at the Lick Observatory at Mt. Hamilton, Calif., and the Keck Observatory in Mauna Kea, Hawaii. "We were astonished to see how bright it got, and how long it lasted."

Full details can be found here.

Cool Jupiter Pictures

NASA's New Horizons probe to Pluto (our fastest ever space probe) has just passed Jupiter, and used the big planet's gravity to boost its speed. The flyby added 9,000 miles per hour, pushing the velocity of New Horizons past 50,000 miles per hour and setting up a flight by Pluto in July 2015. While it was there though, it took some amazing pictures, including Europa rising over Jupiter:

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

...and the most detailed picture ever of the Little Red Spot:

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Also from the article:

Under a range of lighting and viewing angles, New Horizons also grabbed the clearest images ever of the tenuous Jovian ring system. In them, scientists spotted a series of unexpected arcs and clumps of dust, indicative of a recent impact into the ring by a small object.

Movies made from New Horizons images also provide an unprecedented look at ring dynamics, with the tiny inner moons Metis and Adrastea appearing to shepherd the materials around the rings. (Scroll to the middle of this page to see the movies.)

"We're starting to see that rings can evolve rapidly, with changes detectable during weeks and months," said Jeff Moore, New Horizons Jupiter Encounter science team lead from NASA Ames Research Center, Moffett Field, Calif. "We've seen similar phenomena in the rings of Saturn."

Cool!