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You can feel the weight of an object on Earth because of its mass. But what is mass? Flickr/Jeremy Brooks

Explainer: what is mass?

We talk about mass all the time but what is it that actually gives an object mass? And why do some things have mass and others have no mass at all?
A visualisation of gravitational waves emitted by two orbiting supermassive black holes. CSIRO

Where are the missing gravitational waves?

A new study has failed to find evidence of gravitational waves, but that doesn't mean Einstein was wrong about their existence.
Astronaut Cady Coleman harvests one of our plants on Space Shuttle Columbia. NASA

Taking plants off planet – how do they grow in zero gravity?

Plants on the International Space Station must figure out how to grow in a completely novel environment. Their adaptability hints at how they'll react to changes here on Earth – or in future space outposts.
How do we think about something we can’t see and don’t experience in our everyday lives, but seems to be pushing our universe apart ever faster? NASA, ESA, G. Illingworth, D. Magee, and P. Oesch (University of California, Santa Cruz), R. Bouwens (Leiden University), and the HUDF09 Team

Explainer: the mysterious dark energy that speeds the universe’s rate of expansion

Einstein's theory of gravity says dark energy must be out there, accelerating the expansion of our universe. But what is it and how can we try to figure out more about it?
‘I realise it’s got flames on it, but does it go up to 11?’ Channel 4

Scientists at work: building the world’s fastest downhill racer

I’d like to say that it’s not every day you get asked to try to break a world record with a speed-obsessed truck mechanic from Grimsby, but for us at the Centre for Sports Engineering Research it’s starting…
There are millions of these lurking in Earth’s backyard. NASA

Gecko sticking forces hold rubble-pile asteroids together

Millions of asteroids of all shapes and sizes are littered throughout the inner solar system. In the past three decades, scientists have spotted as many as 500,000 but many more remain unseen. Many of…
George and Sandra were relieved to hear they wouldn’t actually be filming in space. Warner Brothers

How Harry Potter magic turned Gravity into Oscar gold

The huge success of Alfonso Cuarón’s Gravity at this year’s Oscars is a genuine cause for celebration for much of the UK film industry – not least for the many visual effects artists involved in its creation…
High-resolution gravity maps – such as this one showing Australia and its northern neighbours – were constructed from three billion calculations. Hirt et al

High-res gravity maps: a fundamental force for engineers

Think back to high-school science. Do you remember what the value of acceleration due to gravity at the Earth’s surface - denoted as “g” in textbooks - is? For those whose memories may need a bit of prodding…
We’re underestimating what primary school students can understand in science. Formula image from

Testing the theory: taking Einstein to primary schools

School students today are taught physics based on obsolete theories and outmoded ways of thinking. Instead of the truth, most learn a naive simplification - the 300 year-old Newtonian physics, itself based…
There’s more to gravity than apples falling from trees. Cea

Explainer: gravity

I have spent almost 40 years trying to detect gravity waves. When I started there were just a few of us working away in university labs. Today 1,000 physicists working with billion-dollar observatories…

Does antimatter weigh more than matter?

Researchers have developed, for the first time, a method to efficiently produce long-lived “positronium” – a bound state…

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