Tag Archives: astronomy

Potentially life-supporting planet found

The four space-based 3 metre telescopes of DARWIN will work together to find other planetsAstronomers have discovered a planet in the 55 Cancri system that orbits constantly in what is know as the ‘habitable zone’ of the solar system. Although the planet is a gas giant some 45 times the size of Earth, there’s a good chance one of its moons might have liquid water and hence encourage the development of earth-like life. Planets are found by studying their transits across the light of a star. By studying the amount the star dims when the planet crosses, the size of the planet can be estimated. This is limited to larger planets currently but future missions like the Kepler and Darwin projects may be able to find rocky planets like our own.

The search for ‘exoplanets’ outside our solar system is hitting its stride and regularly more are found. Whilst the planets found to date are all ‘Jupiters’ like the gas giants further out in our home system, we know that Jupiter, Saturn, Neptune and Uranus all have large satellites. If any of these were in the habitable region where Earth is, the possibility of liquid water and hence bacterial life would be likely. If 55 Cancri did support life on one of its moons it would resemble the world of Coyote in Allen Steele’s excellent series.

[via the guardian, image of Darwin project via Astronomy Online]

New carbon dioxide molecule found to heat Venus more

The green planet may tell us more about how the greenhouse effect worksA big team of astronomers studying Venus’ atmosphere have found a new type of heavier carbon dioxide molecule that absorbs more heat than the one more commonly found on Mars or Earth. The molecule, which is believed to have two additional neutrons in one of its oxygen atoms, allows it to absorb an additional infrared wavelength of 3.3 microns, which is what tipped the teams off to the discovery. They believe this is part of the reason Venus has such a hot atmosphere – the bigger percentage of these molecules creates an even bigger Greenhouse Gas effect than normal CO2.

As soon as I read this article comparing Mars’ cold atmosphere to Venus’ hot one in relation to the quantities of this new molecule, I immediately thought of Kim Stanley Robinson’s ‘Red Mars’. If this gas contributes more global warming than normal CO2, in the future it may be a very valuable tool if we ever came to terraform our red neighbour.

[link and image via ScienceDaily]

Scientists help out SF writers, create list of possible planet types

Chart of exoplanet types

Doing SF writers’ work for them, a U.S. research team has worked out the properties of a variety of weird planet types that could exist in alien solar systems, including graphite planets and carbon monoxide spheres. Of course, they didn’t do it to help writers (though that would be a fine reason do do such a thing): instead, they hope the models will help astronomers identify the properties of exoplanets they discover in the future.

And yes, say the scientists, weird as these worlds are, some of them could harbour life…though not necessarily Life As We Know It.

(Via New Scientist Space.)

(Illustration: Marc Kuchner/NASA-GSFC via New Scientist Space)

[tags]exoplanets, astronomy, science fiction, space[/tags]

Solved: someone found those pesky missing Dwarf Galaxies

Circinus dwarf galaxy

Image courtesy of NASA via spacetoday

A big conundrum in astronomy and cosmology over the last ten years has been the ‘Missing Dwarf Galaxy’ Problem. Dwarf Galaxies are much smaller than normal galaxies and though this makes them fainter and harder to find, astronomers have still been finding far fewer than predicted. The prediction comes from the ‘Cold Dark Matter’ model. Dark matter, which is thought to make up around 22% of all substance in the universe compared to about 2-5% of the matter we can see, forms in distinct ‘halos’, in which real galaxies form. (The remaining 74% of energy density is the mysterious dark energy, responsible for the expansion of the universe.)

By studying the distribution of these dark matter halos, astronomers predicted that a large galaxy such as our own Milky Way should have a hundred or so smaller dwarf satellites. The problem is, until very recently only a handful had been seen. A lot of these could have no visible stars and it was difficult to see a way to detect them. Until now. Two astronomers using the W. M. Keck Observatory in Hawaii think they may have found a load more, possibly solving one of the biggest questions in our study of the stars.

Incidentally, the name for a galaxy smaller than a dwarf class is known as a hobbit galaxy. [via science daily]

Black holes eat black holes

Time-lapse photo of star trails above treesIt’s (relatively) common knowledge that black holes consume pretty much anything and everything … and apparently that includes each other, as astronomers speculate that the black hole at the center of our own galaxy may have gobbled up a smaller sibling over 100 million years ago.

While we’re on the subject of astronomy, and just in case you get asked by a curious child and don’t want to get caught on the hop, you may wish to learn why space is dark. [Image by D P Hershman]