Mars is a small, rocky world that's about half the diameter of Earth. Like our home planet, it has seasons, volcanoes, canyons, weather and polar ice caps.

The average temperature on Mars is minus 80 Fahrenheit. Red dust covers most of its surface and oxidised iron particles in the soil are responsible for this distinctive red colour.

​Mars has clouds and wind just like Earth, but its sand storms can cover the entire planet in a dusty haze for weeks.

The planet is also home to the largest volcanic mountain in the Solar System (Olympus Mons) and it has two small moons, Phobos and Deimos.

There are signs that huge floods once overcame the Martian surface some 3.5 billion years ago and this water may have pooled to form shallow oceans or lakes. It is still unclear where the floodwater came from and what happened to it.

However, Mars is now too cold and its atmosphere is too thin for liquid water to exist on the surface for very long. Findings from NASA'S Mars Reconnaissance Orbiter (MRO) suggest salty liquid water may still flow on Mars.​

Yes. NASA's Mars Exploration Rover Project landed twin rovers Spirit and Opportunity on Mars in 2004. Both missions were only meant to last three months but Spirit worked for six years, and Opportunity is still active.

Also, check out these amazing images from NASA's Curiosity Rover that's been scouring the planet's surface for more than five years.

Not all missions have been as successful, including the UK's Beagle 2 Mars probe and the Schiaparelli rover, which crashed into the Martian surface last year. But there are hopes for an upcoming rover, which should touch down on the Red Planet in 2020. Schiaparelli and the 2020 rover are part of the wider ExoMars mission from ESA (European Space Agency) and Russian space agency Roscosmos.

NASA has ambitious plans to get humans to Mars in the 2030s and the Mars 2020 mission also plans to answer key questions about the potential for life on Mars.

Here are 10 amazing facts you probably didn't know about the Red Planet and you can find out more about NASA's plans to get to Mars here, or find out more about all the Martian missions (past, present and future) here.

Here's a summary of all NASA's work on the Red Planet:

Despite being named after the Roman goddess of love and beauty, there's not much to love about Venus.

​If you landed on the planet, you'd be incinerated by 870 degree Fahrenheit temperatures, burnt alive by clouds of sulphuric acid and crushed by a surface pressure that's 90 times that of the Earth.

There are some similarities between Venus and Earth: including the planets' size, mass, density, composition and gravity. Just like a pair of twins. Except one will kill you instantly and the other nurtures life.

Yes. Quite an extensive list of probes have investigated Venus. NASA first sent the Mariner 2 probe in 1962 and the space agency's last dedicated mission to the planet was Magellan. 

Magellan launched in 1990 and mapped more than 98% of the planet's surface over a four year period. More recently, ESA's Venus Express probe investigated the planet for more than eight years. There are more plans to visit Venus - including a crewed mission from NASA.

Here are some quick fun facts and a more in-depth article about Venus. And here's a video explaining all there is to know about Venus and the closest planet to the Sun, Mercury:

Mercury is a planet of extremes. It's the fastest and smallest planet in the Solar System - and it's also the closest planet to our Sun.

On average, Mercury is just one-third of the distance from the Sun than the Earth is. It's only slightly larger than Earth's moon, but it's incredibly dense - something that has baffled scientists until a recent discovery was made.

To shoehorn in a quick Lego scale example, if Ironman is the same size as the Earth, his helmet would be Mercury:

Mercury has a rocky surface and, much like our Moon's surface, it has a lot of impact craters because there's no atmosphere to burn up any space debris that gets in its way.

This lack of atmosphere also means Mercury sees extremes of temperature.

On the side facing the Sun, temperatures reach a scorching 800 degrees Fahrenheit and, on the other side, temperatures drop to -300 degrees Fahrenheit.

Because Mercury is so close to the Sun, it's difficult to study from the Earth. Although no one has ever stepped on the surface of Mercury, it has had quite a few visits from various spacecraft.

​The most recent is NASA's MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) probe, which orbited Mercury for four years. Some significant findings include evidence of water ice at the planet's poles and that the planet's core makes up 85% of its radius. To compare, Earth's core only makes up 50% of its radius. This massive core explains why Mercury is so dense compared to other planets.

MESSENGER concluded its mission in April 2015 when the probe dramatically slammed into the planet's surface, gouging a new crater in the planet's heavily dimpled surface.

NASA gives a great overview of Mercury here, including information on how the planet got its name, and you can find out more about the MESSENGER mission here.​

This week, NASA's Juno spacecraft flew past the largest planet in our solar system - Jupiter. The planet's 10,000-mile wide spinning storm, called the Great Red Spot, was the craft's primary target.

The images are just starting to come in, but the Juno spacecraft did not disappoint. While it could be months before we understand the full implications of the data and images captured, Jupiter's structure could help us understand more about how the planets in our Solar System* formed.

In the first of a special series on our Solar System, let's find out more about Jupiter.

* The term Solar System just refers to the planets and other bodies orbiting around the Sun.

Jupiter sits between Mars and Saturn in the Solar System, some 484 million miles from the Sun. It takes Jupiter 12 Earth years to orbit the Sun and a "day" is only 10 hours. Jupiter rotates faster than any other planet in our Solar System.

Jupiter is covered in thick red, yellow, brown and white clouds that give it a striped appearance. The planet is classified as a "gas giant". This simply means that it's a very big planet that's made up of gas. 

In fact, it's so big that you could fit more than 1,300 Earths inside Jupiter. Here's a quick Lego scale reference:

But you couldn't stand on Jupiter. It is made up of predominately hydrogen and helium gas so there is no firm ground. 

If you parachuted into the planet then you'd first fall through its visible clouds containing ammonia and hydrogen.

As you approached the centre of the planet, you'd pass through increasingly thicker clouds and the pressure would build until the hydrogen gas assumes a state similar to a metal.

This liquid "metallic hydrogen" could be the source of the planet's incredibly strong magnetic field. 

Questions still remain unanswered around the planet's core so who knows what you'd find there. Some scientists believe the core is a hot molten ball of liquid, others think it could be a solid rock that's up to 18 times more massive than the Earth.

The Juno spacecraft is destined for quite a dramatic finale. At the end of its mission, the craft will fly into Jupiter and burn up as it travels to the core of the planet, gathering plenty of data as it plummets to its death.

Juno's demise isn't planned until February 2018 and the next flyby will come on 1 September 2017, although the spacecraft will not be passing over the storm again soon.

​So, it could be some time before the inner workings of this mysterious planet are unrevealed.

Did you know that if Jupiter was 80 times more massive, it would have formed into a star? And that it has 53 moons and three faint rings? NASA's Jupiter pages are full of fascinating facts about the gas giant.

​It's also hoped that Juno will help us understand planetary formation. Most solar system formation theories focus on giant clouds of gas and dust collapsing until distinct bodies like the Sun and the planets form. What is less clear is how this happens. For example, does a planet's core form first and then all the other layers evolve over time? Or is it a quicker process?

Unlike the Earth, Jupiter is so massive that it has held onto its original composition when the Solar System first came into being, so it gives us a way of tracing our Solar System's history.

The Juno spacecraft is not the first mission to Jupiter - here's a great summary of the nine of missions to the Solar System's largest planet.

And here's the most recent news from the Juno spacecraft, courtesy of the BBC. You can find out all about the mission on the NASA site too and here's a round-up of the craft and its recent images:

Another interesting fact about Jupiter is that it has no song, according to the Moon from comedy series the Mighty Boosh:

Hello. I’m the freelance writer who gets tech. I have two degrees in Physics and, during my studies, I became increasingly frustrated with the complicated language used to describe some outstanding scientific principles. Language should aid our understanding — in science, it often feels like a barrier.
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So, I want to simplify these science sayings and this blog series “Sunday Science” gives a quick, no-nonsense definition of the complex-sounding scientific terms you often hear, but may not completely understand. 

If there’s a scientific term or topic you’d like me to tackle in my next post, fire an email to [email protected] or leave a comment below. If you want to sign up to our weekly newsletter, click here.

Today, a government review of employment practices (the Taylor Report) called for all work in the UK economy to be fair. It focused on the gig economy in particular and recommended such workers have the same rights as permanent staff in terms of holiday and sick pay. And that the self-employed should get paid maternity and paternity leave.

Hear, hear.

Theresa May responded by acknowledging that it was important to have a "flexible" approach that didn't "exploit workers", while the unions slammed the report for its "spectacular failure" to deliver on promises.

I think I may agree with, um, May. We need to introduce flexibility into future legislation so that every worker is protected from exploitation and is paid a fair amount for their time.

Today, I spoke to the BBC Radio 4 show You and Yours about the report and my life as a freelancer. When asked how fair my pay and conditions are, I have to admit that they're more than fair.

Self-employment is, to me, a huge opportunity. ​I chose to work this way. I chose to leave permanent employment with its protection and rights for workers because, as the freelance writer who gets tech, I can command a higher income and achieve a better work/life balance.

So, do I have the right to ask for extra rights? Does the very nature of self-employment not mean that I am already compensated for the lack of maternity leave, pension or sick pay?

Should all self-employed workers just be grateful for what they have?

No. The real problem is that no two self-employed workers are the same. It's the lack of definition around the way I and others in the self-employment sector work that is dangerous for the future of work and, ultimately, the British economy.

The lack of clarity around defined worker roles is the real problem that the Taylor report failed to address.

​​The Taylor report introduced a new "dependent contractor" category that sits between fully employed and self-employed status. Dependent contractors would be eligible for certain rights and companies, like Uber and Deliveroo, that rely on these workers would not be able to dodge their obligations.

However, I am not a dependent contractor. I do not rely on the gig economy. I use it to fund a small fraction of my income as and when I need to. My working situation is a world away from a zero hours contract. I'm not an Uber driver. 

So, what am I?

I'm self-employed. I'm one of almost five million British workers that count themselves as self-employed and, arguably, prop up the British economy.

Ahead of the Taylor Review, a survey by PwC  suggested more people would consider gig work or a zero-hours contract if they had better guarantees around pay, job security and benefits such as holiday and sick pay.

Surely, more employment in any guise means more wealth and should be widely encouraged?

Yet, the Taylor Review has deemed it necessary to introduce a hybrid "dependent contractor" category, without first providing a statutory definition of self-employment. And this is a huge oversight.

Whether you're a permanent employee, self-employed or somewhere in between, we first need to be clear about the boundaries between different worker roles so we can give all workers the rights they deserve.

Speaking in a statement, Chris Bryce, chief executive at self-employment association IPSE,  said: "Any changes to employment status should bring clarity and not add to the confusion around how government treats the way people choose to work." 

"When people talk about the gig economy, there is often the mistaken assumption that the services operating in it are all the same. Each relationship has to be judged on its own particular merits, and it would have been a huge error to simply place everyone in the gig economy within the revised worker status. This is why it’s essential to enshrine what it means to be self-employed in law," he added.

If the ultimate goal of the Taylor Review was to protect all workers' rights, then it needs to first give the self-employment sector the recognition  it deserves.

As Theresa May takes the summer to flick through the report and plan her next move, I sincerely hope the self-employment sector is not left on the sidelines.

We all have the right to a fair deal at work.

Nuclear energy is released when you interfere with the nucleus that sits at the centre of an atom.

There are two ways to release nuclear energy: nuclear fission and nuclear fusion.​

During nuclear fission, a heavy nucleus either splits spontaneously or splits because it collides with another particle. Fission is another word for splitting.

During nuclear fusion, a light nucleus is fused with another light nucleaus to form a heavy nucleus.

​Here's a quick Lego example where two nuclei are fused together to form a bigger nucleus, and some energy is released.

No. Only nuclear fission can be used to generate electricity in nuclear reactors.

​Uranium or plutonium isotopes are often used in fission because these large nuclei are easy to split. (Isotopes are just atoms with a few extra neutrons shoved in.) Neutrons are fired at the large isotopes to help them split up.

Let's look at another example. Ironman fires a tiny yellow neutron at a large nucleus. This causes the nucleus to split into two smaller nuclei, a couple of neutrons and some energy is released. 

​If you have lots of uranium or plutonium isotopes, then these two or three released neutrons may also hit other uranium or plutonium nuclei.

Then, these nuclei will split and release more neutrons and energy. This, in turn, can cause more nuclei to split. And so on. This is called a chain reaction.

The chain reaction in a nuclear reactor is controlled to stop it getting out of control. And the nuclear energy released is captured and used to create electricity.

The Sun and other stars use a sequence of nuclear fusion reactions to release energy. In simple terms, hydrogen nuclei are fused together to form helium, which causes an energy release.

However, in the Sun massive gravitational forces create the right conditions for fusion - and these are incredibly difficult to replicate on Earth. If we could recreate fusion, then we would have an energy source that produces very short-lived nuclear waste.

The waste produced in nuclear fission, however, takes much longer to decay. The Plutonium-239 isotope, for example, takes 24,000 years for its radioactivity to drop by half.
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Fusion has a chequered past in the scientific community, but progress is being made in the nuclear fusion field.

If a stable nuclear fusion power plant was created on Earth, it could solve the planet's energy crisis.

Here's a great explanation covering nuclear fusion and the challenges it presents from the World Nuclear Association. And New Scientist covers the topic of nuclear energy quite extensively.

This week, the Chinese reportedly got one step closer to a steady state nuclear fusion operation. Here's a nice retro video from the BBC explaining the differences between nuclear fission and fusion: