Four things everyone should know about space

Why does space need cleaning? What does the study of black holes help uncover? Researchers have the answers.

Space may seem vast and far away, but the things taking place there affect our daily lives. The significance of space on Earth continues to grow along with technological advances, also in terms of commerce: in total, the annual scope of the space economy is already roughly €370 billion. This number is rising rapidly, and businesses are increasingly interested in exploiting space.

Here, we list four space-related topics you should be familiar with.

1. Space debris must be cleaned up to ensure orbital safety

Smartphone navigation, GPS signals and many other everyday applications rely on satellites. However, the useful life of satellites is not limitless, and if they remain in orbit, the amount of debris will increase. Orbits congested by debris are a threat to other satellites.

– As with climate change, the situation will be difficult to remedy if things get too bad, says Markus Battarbee, a university researcher specialising in space physics.

The problem is that satellites at the end of their service life must be directed either to the Earth’s atmosphere to burn up or to a ‘graveyard orbit’ for satellites, which usually requires fuel. The Centre of Excellence in Research of Sustainable Space investigates, among other things, easier ways to deal with the problem.

– The FORESAIL-1 satellite launched in the early summer is being used to test an electrically charged tether that serves as a sail. This is revolutionary as an invention, as the sail eliminates the need for any fuel to change the orbit of the satellite, Battarbee says.

Getting satellites down safely is important, because Earth has a limited number of orbit paths and the number of satellites is growing rapidly. Space businesses and international space operators must assume responsibility for satellites by not leaving them in place at the end of their useful life and being aware of the risks caused by debris.

– By clearing the debris, we ensure the continued utilisation of technology, says Battarbee.

2. Solar flares affect technology

Even though life on Earth is dependent on the Sun, few people realise that our closest star can also influence technology from electric grids to GPS satellites. Recently, the potential damage caused by a major solar flare has become an increasingly discussed topic.

– Intensified particle radiation during a geomagnetic storm can damage the sensitive instruments of satellites in many ways, necessitating corrections to their paths, says Professor of Space Science Emilia Kilpua.

Rapid changes in the electromagnetic fields surrounding Earth can cause harmful surges in electrical grids and natural gas pipelines, disrupt the flow of radio signals and make it necessary to adjust aircraft routes crossing the polar regions. We should be considering how well we are prepared for space weather disturbances and how accurately they can be predicted.

– The problem is the short notice. Data on direct observations arrive only 30 to 60 minutes before a solar flare hits Earth, Kilpua says.

In fact, Kilpua’s research group has developed a range of means for modelling and predicting the behaviour of solar flares on the basis of remote sensing observations, which can help in preparing for problems.

The topic is current.

– The Sun’s sunspot numbers are growing at a significant pace, making it possible that larger flares will be seen in the autumn, Kilpua says.

Good news for spotters of celestial light phenomena: this is likely to result in an active winter in terms of northern lights.

3. The history of the solar system can be investigated by studying asteroid properties

In June, the third observational dataset produced by the Gaia space mission was announced. Gaia is surveying the stars of the Milky Way and, among other things, the asteroids of the solar system. Once supercomputers have analysed the data now released, the number of asteroids whose mass is known precisely may rise from dozens to hundreds.

– There are many reasons for studying asteroids. The first is, of course, to determine their orbits to find out whether any of them pose a collision risk to Earth. At the same time, it’s important to investigate their composition as well as their density derived from mass and volume. These details help us determine, for example, how the solar system was born and has evolved, says Associate Professor of Planetary Astrophysics Mikael Granvik.

The mass of asteroids can be estimated on the basis of how they alter the orbits of other asteroids in close encounters. Volume is assessed based on the asteroid’s brightness and its variation. Composition is investigated particularly through spectral analysis.

– The properties of asteroids vary considerably depending on the substances they are made of and their porousness, says Granvik.

This autumn also offers a significant event in asteroid research, more specifically in a field known as planetary defence, as NASA will collide its DART probe into the moon of an asteroid with the aim of altering the path of the moon. If the mission succeeds, the method could also be used to change the paths of asteroids threatening the Earth.

– Everything is going according to plan, and the collision is expected to take place on Tuesday, 27 September at 2.14 at night EEST. The DART probe will provide data on the object of the impact only just before the collision, but the body has already been observed using telescopes and modelling for more than 26 years, says Granvik.

4. Black holes can help refine key theories in physics

There are no black holes near Earth. Instead, all of them are located much further away in space. Unlike the other topics listed here, they pose no threat to Earth. However, their study provides a lot of important information.

– A black hole can be created when a massive star with a mass of at least 15 to 20 solar masses goes supernova. As a result of the explosion, the core of the star may collapse into a black hole, creating an area of such enormous gravitational pull that even light cannot escape, says Professor of Astrophysics Peter Johansson.

In May 2022, researchers succeeded in capturing an image of the shadow of a black hole in the centre of the Milky Way.

– The imaged object is known as a supermassive black hole. Most black holes are much smaller, stellar-mass black holes, and these smaller ones have also been observed by measuring gravitational waves, Johansson says.

The mass of the supermassive black hole in the Milky Way is only roughly four million solar masses, while the largest supermassive black holes can have the mass of more than 10 billion Suns.

For the past five years, the study of black holes has undergone a renaissance of sorts thanks to new observations and, in particular, gravitational wave measurements.

– Among other things, black holes can help us refine the fundamental theories of physics. Researchers are investigating whether there are differences in the validity of the general theory of relativity close to black holes. So far, the theory has been very accurate, Johansson says.

Other matters to investigate include the effects of supermassive black holes on galaxies, and whether they affect the formation of stars and, consequently, the number of stars in the universe. There is plenty to explore.

– There are an estimated 100 million stellar-mass black holes in our Milky Way and one supermassive black hole in its centre.

Look up! Space in 10 minutes

What happens in space and orbits is reflected in our everyday lives.

Join us at Think Corner on 13–23 September to learn what is being explored and done in space right now – and how it affects life on Earth.

In the 'Avaruus 10 minuutissa' ('Space in 10 minutes') event at Think Corner on 13 September from 17.00 to 18.15, researchers from the University of Helsinki will present four current perspectives on space. These are the things that we should all be keeping up with right now.

The presentations will be given by space physicist Markus Battarbee, astronomer Mikael Granvik, theoretical astrophysicist Peter Johansson and space physicist Emilia Kilpua. The event is hosted by Liisa Mayow.

The event is part of Think Corner’s Look up series, which takes attendees sky high to the cutting edge of the development of space operations. Follow events on location, stream them live, or view recordings later. 

Join us on a journey to space!