Using the oldest fossil micrometeorites - space dust - ever found, Monash University-led research has made a surprising discovery about the chemistry of Earth's atmosphere 2.7 billion years ago.

The findings of a new study published today in the journal Nature - led by Dr Andrew Tomkins and a team from the School of Earth, Atmosphere and Environment at Monash, along with scientists from the Australian Synchrotron and Imperial College, London - challenge the accepted view that Earth's ancient atmosphere was oxygen-poor. The findings indicate instead that the ancient Earth's upper atmosphere contained about the same amount of oxygen as today, and that a methane haze layer separated this oxygen-rich upper layer from the oxygen-starved lower atmosphere.

Unlike most asteroids, C/2014 S3 (PANSTARRS) was formed in the inner Solar System at the same time as the Earth itself, but was ejected at a very early stage and has not been baked by billions of years near the Sun.

Instead, it has been preserved in the best freezer there is: the Oort Cloud, a huge region surrounding the Sun like a giant, thick soap bubble. It is estimated that it contains trillions of tiny icy bodies.

C/2014 S3 (PANSTARRS) was originally identified by the Pan-STARRS1 telescope as a weakly active comet a little over twice as far from the Sun as the Earth. Its current long orbital period (around 860 years) suggests that its source is in the Oort Cloud, and it was nudged comparatively recently into an orbit that brings it closer to the Sun.

You can never predict what treasure might be hiding in your own basement - a year ago, a 1917 image on an astronomical glass plate from the Carnegie Observatories' collection shows the first-ever evidence of a planetary system beyond our own Sun. 

Here's what happened: about a year ago, the review's author, Jay Farihi of University College London, contacted our Observatories' Director, John Mulchaey. He was looking for a plate in the Carnegie archive that contained a spectrum of van Maanen's star, a white dwarf discovered by Dutch-American astronomer Adriaan van Maanen in the very year our own plate was made.

Are you keen on humans in space, but skeptical about colonization of Mars as our first objective for space exploration? Do you think we will start with settlements supported from Earth, such as we already have in inhospitable places such as Antarctica? Do you think our exploration should be open ended with science as a core objective, and planetary protection and reversible biological exploration as core principles?

If you are keen on Mars colonization, it is not hard to find a future vision to inspire you. Elon Musk has plans to send a hundred people at a time in his proposed "Mars Colonial Transporter" and found a city of 80,000, and eventually a million. He is due to reveal these plans at the IAC conference this September.

This is one of the questions I get asked most often since I started to cover the topic of asteroid impacts. Will humans will become extinct within a decade, or within a century? And can this happen through natural disasters? For instance if you watch the movies you may think there's a chance of a giant asteroid impact which will make us extinct. But what's the real situation? 

In case you haven't heard of it, Nibiru is a totally nuts idea. Yet it gets many people very scared. I started to get messages about it as a result of writing articles about asteroid impacts, and how we can detect and deflect asteroids. It is possible to have beliefs that don't make any sense if you look at them closely. For instance, if you believe that you can have a square with every point on its edges equally distant from its center in ordinary geometry - that's impossible. That's a square circle. Nibiru is a belief of this sort.

Solar storms trigger Jupiter's intense 'Northern Lights' by generating a new X-ray aurora that is eight times brighter than normal and hundreds of times more energetic than Earth's aurora borealis, new research finds. 

It is the first time that Jupiter's X-ray aurora has been studied when a giant storm from the sun has arrived at the planet.

The dramatic findings complement NASA's Juno mission this summer, which aims to understand the relationship between the two biggest structures in the solar system - the region of space controlled by Jupiter's magnetic field (its magnetosphere) and that controlled by the solar wind.

I wrote this soon after ExoMars's successful launch to Mars, 2015. Hurray! In the program about the mission, before and during the launch, the presenters talked about the care they take to sterilize the lander of microbes to protect Mars. And indeed, kudos to all the space faring countries, and the planetary protection officers, for doing this. But in the same program they talked about ideas to send humans to Mars, talking about all its benefits. For some reason it never seems to occur to anyone to ask if humans can be sterilized in the same way as robots. There is nothing unusual about this - it's the same for programs from NASA, or programs about Mars on UK television, and anywhere.

NASA hopes to go full speed ahead with its "Road to Mars" to land humans on the planet, and Elon Musk wants to build a city of a million on Mars by 2100, but it is rare for anyone in the debates to mention planetary protection. I think many assume it has already been dismissed by simple arguments like this one of Zubrin's - but far from it. As some of the listeners said to me when I was guest on the Space Show last Monday, the disconnect is enormous.