Prolonged spaceflight may give you a nasty case of diarrhea, at least if you are a mouse. Specifically, when mice were subjected to simulated spaceflight conditions, the balance of bacteria and the function of immune cells in the gut changed, leading to increased bowel inflammation.  

What do you say to Pluto’s demotion to “dwarf planet” status?  I did not approve of the demotion, but a few days ago our BBC Sky at Night team did give a reasonable reason why it does require a new category.  With Neptune, one can say “planets end here”, while Pluto is the first of many bodies such as the remarkable Eris that we now know inhabit the Kuiper Belt. 

NASA’s announcement of the discovery of a new extrasolar planet has been met with a lot of excitement.

But the truth is that it is impossible to judge whether it is similar to Earth with the few parameters we have – it might just as well resemble Venus, or something entirely different.

There is so much over enthusiastic hype about this planet today, I thought could do with a bit of more sober reporting of the results, interesting though they are. Much of that speculation derives from just one phrase in the press release I think, where they say:  "Today, and thousands of discoveries later, astronomers are on the cusp of finding something people have dreamed about for thousands of years -- another Earth." The idea of what that means by "another Earth" for astronomers who know the capabilities of Kepler, is rather different from what most of the general public would think of when you say "another Earth".

Galaxies in a cluster roughly 300 million light years from Earth could contain as much as 100 times more dark matter than visible matter, according to an Australian study. The research used computer simulations to study galaxies that have fallen into the Coma Cluster, one of the largest structures in the Universe in which thousands of galaxies are bound together by gravity.

"It found the galaxies could have fallen into the cluster as early as seven billion years ago, which, if our current theories of galaxies evolution are correct, suggests they must have lots of dark matter protecting the visible matter from being ripped apart by the cluster."

A type of two-star system known as a Cataclysmic Variable, where one super dense white dwarf star is stealing gas from its companion star, effectively 'cannibalizing' it, has been found by citizen scientists. It is the first known such system where one star completely eclipses the other. 

The system, named Gaia14aae, is located about 730 light years away in the Draco constellation. Amateurs discovered it in data from the European Space Agency's Gaia satellite of August 2014, when it suddenly became five times brighter over the course of a single day.

Pluto really does seem to have captured people’s imagination.  With the announcement that the (dwarf) planet is larger than we thought, a neighbour was asking me how one measured its size.

This got me looking up some values in Pluto Is Larger Than Thought, Has Ice Cap, NASA Probe Reveals, from

The new measurement of Pluto is 1,473 miles (2,370 kilometers) across

The previous estimate from Earth was 1,430 miles (2,301 km).

Pluto does not meet the definition of a planet but as we will see that does not diminish it.  Far from a random and uninteresting chunk of ice, with little local gravitational influence on it’s neighborhood, it is an example of binary planetoids with tantalizing features. 


ET phone Earth!

We could be on the verge of answering one of the essential questions of humanity that has captivated our minds for centuries.

There may be far fewer galaxies further out in the Universe then might be expected, suggests a new study based on simulations and published this week in the Astrophysical Journal Letters.

The simulations show the first results from the Renaissance Simulations, a suite of extremely high-resolution adaptive mesh refinement (AMR) calculations of high redshift galaxy formation and hundreds of well-resolved galaxies. 

"Most critically, we show that the ultraviolet luminosity function of our simulated galaxies is consistent with observations of redshift galaxy populations at the bright end of the luminosity function, but at lower luminosities is essentially flat rather than rising steeply," wrote researchers in their paper.