Science

Physicists consider black holes one of the most mysterious objects that exist. Ironically, they’re also considered one of the simplest. For years, physicists like me have been looking to prove that black holes are more complex than they seem. And a newly approved European space mission called LISA will help us with this hunt.

Research from the 1970s suggests that you can comprehensively describe a black hole using only three physical attributes – their mass, charge and spin. All the other properties of these massive dying stars, like their detailed composition, density and temperature profiles, disappear as they transform into a black hole. That is how simple they are.

Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to curiouskidsus@theconversation.com.

Most Americans don’t know two key facts about pregnancy, including how they are dated and how long a trimester is – and this could matter, as a growing number of states place restrictions on abortion.

Florida enacted a new law on May 1, 2024, that bans abortions after six weeks of pregnancy, with a few exceptions – including documented rape, incest and to save the life of the mother.

Google on Tuesday said it would introduce AI-generated answers to online queries, in one of the biggest changes to its world leading search engine in 25 years.

"I'm excited to announce that we will begin launching this fully revamped experience, 'AI overviews,' to everyone in the US this week," Google chief executive Sundar Pichai said at an event in California.

Last year's northern hemisphere summer was the hottest in 2,000 years, according to a new study published on Tuesday.

Scientists say 2023 was the hottest year globally since records began in 1850, but the study in the journal Nature indicates human-caused climate change pushed northern summer highs well beyond anything seen in two millennia.

You’ve likely heard that you can get iron from eating spinach and steak. You might also know that it’s an essential trace element that is a major component of hemoglobin, a protein in red blood cells that carries oxygen from your lungs to all parts of the body.

A lesser known important function of iron is its involvement in generating energy for certain immune cells.

On Saturday evening before Mother’s Day, Australians witnessed a rare celestial spectacle: a breathtaking display of aurora australis, also known as the southern lights.

Social media was flooded with photos of the vivid pinks, greens and blues lighting up the skies from local beaches and backyards all over the country.

Auroras are normally visible near Earth’s north and south poles. In Australia, they are typically only seen in Tasmania. However, due to rare and special space weather conditions, this time people could see them as far north as Queensland.

The Australian Space Weather Forecasting Centre first issued a potential extreme (G5, most severe level) geomagnetic storm warning on Saturday morning.

Lucky Australians who received this warning, and those who happened to look outside that evening, were rewarded with an amazing spectacle. However, by sunset on Sunday, the chance of aurora had subsided, leaving many hopeful viewers in the dark.

What happened? Why are auroras so hard to predict, and how reliable are aurora forecasts? To answer this, we need to know a bit more about space weather.

What is space weather?

Auroras on Earth are related to the Sun’s magnetic field. The Sun’s activity increases and decreases over an 11-year period called the solar cycle. We are currently approaching the solar cycle maximum, meaning there’s a higher number of sunspots on the Sun’s surface.

These sunspot regions have intense magnetic fields, which can lead to huge explosions of electromagnetic radiation called “solar flares”, and eruptions of material into space, called “coronal mass ejections”.

When this material is directed towards Earth, it collides with Earth’s protective magnetic field, kicking off a series of complex interactions between the magnetic field and the plasma in the ionosphere, part of Earth’s upper atmosphere.

The charged particles resulting from these interactions then interact with the upper atmosphere, causing beautiful and dynamic auroras. The conditions in space produced by this chain of events are what we call “space weather”.

Everyday space weather generally poses no threat, but these events – known as geomagnetic storms – can impact power supply, satellites, communications and GPS, potentially leaving lasting damage.

Saturday’s dazzling display was produced by the most intense geomagnetic storm since November 2003. Fortunately, this time there have been no reports of major disruptions to power grids, but SpaceX’s Starlink constellation was reportedly impacted.

Why are geomagnetic storms hard to predict?

Last weekend’s geomagnetic storm was caused by a large and complex region of sunspots that launched a series of solar flares and a train of coronal mass ejections.

Space weather prediction is challenging, and the physics is complex. Even when we see an eruption on the Sun, it’s not clear if or when it will hit Earth, or how strong the effects might be.

Predicted arrival times can be off by up to 12 hours, and it is only when the eruption arrives at monitoring spacecraft close to our planet that can we can gauge the strength of an impending geomagnetic storm.

As a result, aurora hunters really only have up to a few hours advanced notice to decide whether venturing outside is worthwhile or not.

Can we expect more auroras soon?

At the time of writing, the sunspot region responsible for the recent display is still spitting out X-class flares and eruptions, but it’s no longer facing Earth directly. It is possible this region will still be active when it faces Earth again, but this remains to be seen.

However, as we approach solar cycle maximum, other large complex sunspot regions are likely to form and, if the conditions are right, produce more spectacular aurora displays.

Aurora australis captured from Joyce’s Creek, Victoria on May 11. Patrick Kavanagh/Flickr, CC BY

How to check for aurora forecasts?

Thousands of Australians lined the beaches looking towards the horizon on Sunday night hoping for a second show, only to be disappointed. Official space weather and aurora forecasts provide a wide range of possibilities that must be communicated with the appropriate nuance.

The most reliable sources of information about space weather and aurora are agencies such as the Bureau of Meteorology’s Australian Space Weather Forecasting Centre or the United States NOAA Space Weather Prediction Center.

Not only do they provide aurora forecasts, but they also play a vital role in safeguarding infrastructure from the negative impacts of space weather.

Space weather research

Looking ahead, scientists in Australia and around the world are working hard to improve our understanding and prediction of space weather events.

By studying the Sun’s magnetic activity and developing advanced forecasting models of the complex processes that happen between the Sun and Earth, we can better predict and prepare for future space weather events.

A better understanding will help protect important technologies that we rely upon. It will also alert people to step outside and witness a phenomenon that not only lights up the sky, but ignites a profound sense of wonder.

Anthropic on Monday announced that its artificial intelligence assistant "Claude" is available in Europe after launching in the United States earlier this year.

"We’re excited to announce that Claude, Anthropic's trusted AI assistant, is now available for people and businesses across Europe to enhance their productivity and creativity," the San Francisco-based tech startup said in a blog post.

Roman dodecahedra are something of an enigma: there is no known mention of these 12-sided, hollow objects in ancient Roman texts or images. First discovered in the 18th century, around 130 dodecahedra have been found across the Roman Empire, although it is interesting that the majority have been found in northern Europe and Britain, and none have been found in Italy.

Dodecahedra are quite intricate, featuring a number of round holes, with knobs framing the holes. It would have taken a very skilled craftsman to make them. They are made out of a copper alloy and would have been quite expensive, due to the amount of time and metal that was used to create them, which adds to their intrigue.

Fifty countries are meeting in France on Tuesday to discuss the lack of access to clean cooking methods worldwide which causes millions of deaths every year and fuels global warming.

Some 2.3 billion people across 128 countries breathe in harmful smoke when they cook on basic stoves or over open fires, according to an International Energy Agency (IEA)-African Development Bank (ADB) report that sounded the alarm last year.