In the early Universe, things were quite different. The first stars were much more massive than stars today, and contained mostly Hydrogen. Astronomers have good ideas about how they formed, but other objects from around this time, namely black holes, are much tougher to account for. Early black holes were huge, with no explanation for how they grew so large. “Early” means “first Billion years after the Big Bang,” but even in that time, it’s hard to determine how observed black holes could grow as large as 100,000 solar masses. I say 100,000 solar masses, because that is the mass of two ‘seed’ black holes, discovered...
We know that galaxies like our Milky Way are far more massive than we can see. The dark matter in the Milky Way makes up 90% of it’s total mass. Another way of saying this is the Mass to Light ratio, comparing the total mass inferred by the rotation speed of the galaxy to the total mass of stars in the galaxy. This ratio, M/L, for the Milky Way, is about 10. But for a galaxy cluster, the M/L ratio is more like 100. Galaxy clusters are not just dense collections of stars and massive galaxies, they are also immense...
We are reaching the point in our study of exoplanets, planets orbiting other stars, where the atmospheres of distant worlds are within the limits of our technology. Once we could barely see the wobble of a star, the telltale sign of an exoplanet, and now we can see reflected starlight and study a distant atmosphere. Now we can probe deeper questions, are atmospheres of exoplanets similar to solar system planets? What are they made of? Do other solar systems have the same raw materials as ours? Do they have what we believe to be the raw materials for life? A...
As we push the limits of our technology, we naturally will find the biggest, the brightest, the smallest, the most extreme, and of course the most distant objects in the universe. We are at the time in history where we are beginning to see the edges of our universe in unprecedented detail. Eventually will will stop finding the biggest, brightest, and most distant, after which point our technology will serve to improve our precision and allow us to peer within these unique objects. Astronomers have used this incredible technology to discover the most distant galaxy in the universe, forming only...
NASA had announced a press conference for yesterday afternoon to reveal amazing findings that would ‘change how we look at galaxies.’ And they did just that, sort of. Findings from the Cosmic Infrared Background Experiment (CIBER) reveal that there is a huge surplus of Infrared light present in the vast darkness that exists between Galaxies. Infrared light is invisible to the human eye, but is emitted by most room temperature objects. It fills the EM spectrum at wavelengths longer than visible light (See yesterday’s post for the EM spectrum). This surplus of light is greater than what we would expect from galaxies...
I’ve seen a lot of lovely images from the Spitzer Space Telescope. It takes infrared images and can see the fine structure of galaxies, where stars are forming and where they are not forming. The photos paint a picture of the history and evolution of a galaxy. The latest image released last week shows some amazing features. The Cyan light in the image is a combination of blue and green coloured light representing infrared wavelengths of light at 3.4 and 4.5 microns. This wavelength shows the stellar population in the galaxy. The red light is representing dust features that glow...
