BepiColombo captured images of Earth during its recent flyby

Farewell! Even though the BepiColombo mission launched for Mercury in 2018, it’s still hanging around the Earth – at least, briefly, as shown in this stunning image recently released by the European Space Agency.

In the image, the Earth hangs serenely in between BepiColumbo’s magnetometer boom (on the right) and its medium-gain antenna (on the left).

But the Earth flyby wasn’t without its tense moments. The spacecraft relies on solar power, and during the loop around Earth it had to spend some time in our planet’s shadow – and out of the sun. To prepare, the mission scientists made sure that BepiColombo was fully charged and nice and warm before the maneuver.

And on April 10, the date of the flyby, it all went swimmingly.

The spacecraft is on a long, winding journey sunwards towards the smallest planet in the solar system, making loop after loop first around Earth, then Venus a couple times, then Mercury itself half a dozen times before parking itself in orbit. The frequent loops are necessary because at launch BepiColombo was traveling at the same speed as the Earth in its orbit (29.78 km/s), and needs to match that of Mercury (47.36 km/s), and it does so by borrowing some energy from the planets themselves.

Once BepiColombo reaches Mercury, it will separate into two individual probes: the Mercury Planetary Orbiter and the Mercury Magnetospheric Orbiter. The twin orbiters will attempt to answer several challenging riddles about the planet nearest to the sun, like the origins of Mercury’s faint-but-still-there magnetic field and atmosphere, and the craters pitting its surface.

But it will take a long time to get there. BepiColombo’s final arrival at Mercury isn’t scheduled until December of 2025, showing how reaching the inner planets of our system can be sometimes more difficult than journeys outward – it turns out that doing planetary dances is more challenging than you might think.

The Intense Heat from the Sun Helps Ice Form on Mercury. Wait… What?

While the scorching planet Mercury might not be the first place you’d think to look for ice, the MESSENGER mission confirmed in 2012 that the planet closest to the Sun does indeed hold water ice in the permanently-shadowed craters around its poles.  But now a new study regarding Mercury’s ice provides even more counter-intuitive details about how this ice is formed. Scientists say heat likely helps create some of the ice.

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Satellites Watched Mercury’s Transit From Space, Confirming That Yes, the Sun Has At Least One Planet

Do you wonder how astronomers find all those exoplanets orbiting stars in distant solar systems?

Mostly they use the transit method. When a planet travels in between its star and an observer, the light from the star dims. That’s called a transit. If astronomers watch a planet transit its star a few times, they can confirm its orbital period. They can also start to understand other things about the planet, like its mass and density.

The planet Mercury just transited the Sun, giving us all an up close look at transits.

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Mercury has Magnetic Poles that Drift Like Earth’s

Earth’s magnetic poles drift over time. This is something that every airplane pilot or navigator knows. They have to account for it when they plan their flights.

They drift so much, in fact, that the magnetic poles are in different locations than the geographic poles, or the axis of Earth’s rotation. Today, Earth’s magnetic north pole is 965 kilometres (600 mi) away from its geographic pole. Now a new study says the same pole drifting is occurring on Mercury too.

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There May be Thick Ice Deposits on the Moon and Mercury

In addition to being the only solvent that is capable of supporting life, water is essential to life as we know it here on Earth. Because of this, finding deposits of water – whether in liquid form or as ice – on other planets is always exciting. Even where is not seen as a potential indication of life, the presence of water offers opportunities for exploration, scientific study, and even the creation of human outposts.

This has certainly been the case as far as the Moon and Mercury are concerned, where water ice was discovered in the permanently-shadowed cratered regions around the poles. But according to a new analysis of the data from the Lunar Reconnaissance Orbiter and the MESSENGER spacecraft, the Moon and Mercury may have significantly more water ice than previously thought.

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Mercury-Bound BepiColombo is About to Start Using the Most Powerful Ion Engines Ever Sent to Space

An artist's impression of the BepiColombo spacecraft as it approaches Mercury at the end of its 7 year journey. Image: spacecraft: ESA/ATG medialab; Mercury: NASA/JPL

A handful of spacecraft have used ion engines to reach their destinations, but none have been as powerful as the engines on the BepiColombo spacecraft. BepiColombo is a joint mission between the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA.) It was launched on October 20, 2018, and has gone through weeks of in-flight commissioning. On Sunday it turned on its powerful ion thrusters for the first time.

“We put our trust in the thrusters and they have not let us down.” – Günther Hasinger, ESA Director of Science.

BepiColombo is a three-part spacecraft. It has two orbiters, the Mercury Planet Orbiter (MPO) built by the ESA, and the Mercury Magnetospheric Orbiter (MMO) built by JAXA. The third part is the Mercury Transfer Module (MTM), built by ESA. The MTM is the propulsion part of the spacecraft and contains the spacecraft’s four ion engines.

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How Science Journalism Helped Me Become a Better Sci-Fi Writer

Hello all. I hope our readers don’t mind that I’m taking a bit of a diversion here today to engage in a little shameless self-promotion. Basically, I wanted to talk about my recently-published novel – The Jovian Manifesto. This book is the sequel to The Cronian Incident, which was published last year (and was a little  shamelessly promoted at the time).

However, I also wanted to take this opportunity to talk about hard science fiction and how writing for a science publication helped me grow as a writer. By definition, hard sci-fi refers to stories where scientific accuracy is emphasized. This essentially means that the technology in the story conforms to established science and/or what is believed to be feasible in the future.

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Forming Dense Metal Planets like Mercury is Probably Pretty Difficult and Rare in the Universe

The planet Mercury, the closet planet to our Sun, is something of an exercise in extremes. Its days last longer than its years and at any given time, its sun-facing side is scorching hot while its dark side is freezing cold. It is also one of the least understood planets in our Solar System. While it is a terrestrial (i.e. rocky) planet like Earth, Venus and Mars, it has a significantly higher iron-to-rock ratio than the others.
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A New Extrasolar Planet Has The Composition of Mercury, but 2.5 Times the Mass of Earth

In the course of searching for planets beyond our Solar System – aka. extra-solar planets – some truly interesting cases have been discovered. In addition to planets that are several times the size of the Solar System’s largest planet (Super-Jupiters), astronomers have also found a plethora of terrestrial (i.e rocky) planets that are several times the size of Earth (Super-Earths).

This is certainly true of K2-229b, a rocky planet that was recently discovered by an international team of astronomers. Located 339 light years away, this hot, metallic planet is an exercise in extremes. Not only is it 20% larger than Earth, it is 2.6 times Earth mass and has a composition similar to Mercury. On top of that, its orbits its star so closely that it is several times hotter than Mercury.

The study which details their discovery recently appeared in the journal Nature under the title “An Earth-sized exoplanet with a Mercury-like composition“. The study was led by Alexandre Santerne, a researcher from the Laboratoire d’Astrophysique de Marseille (LAM) at the Aix-Marseille Université, and included members from the the European Southern Observatory (ESO), the University of Warwick, the Universidade do Porto, and multiple universities and research institutions.

The newly-discovered exoplanet K2-229b is 20% larger than Earth, but has a composition like Mercury. Credits: NASA/JHUAPL/Carnegie Institution of Washington/USGS/Arizona State University

Using data from the Kepler space telescopes K2 mission, the team was able to identify K2-229b, a Super-Earth that orbits a medium-sized K dwarf (orange dwarf) star in the Virgo Constellation. Using the Radial Velocity Method – aka. Doppler Spectroscopy –  the team was able to determine the planet’s size and mass, which indicated that it is similar in composition to Mercury – i.e. metallic and rocky.

They were also able to determine that it orbits its star at a distance of 0.012 AU with an orbital period of just 14 days. At this distance, K2-229b is roughly one one-hundredth as far from its star as the Earth is from the Sun and experiences surface temperature that are several times higher than those on Mercury – reaching a day side temperature 2000 °C (3632 °F), or hot enough to melt iron and silicon.

As Dr. David Armstrong, a researcher from the University of Warwick and a co-author on the study, explained:

“Mercury stands out from the other Solar System terrestrial planets, showing a very high fraction of iron and implying it formed in a different way. We were surprised to see an exoplanet with the same high density, showing that Mercury-like planets are perhaps not as rare as we thought. Interestingly K2-229b is also the innermost planet in a system of at least 3 planets, though all three orbit much closer to their star than Mercury. More discoveries like this will help us shed light on the formation of these unusual planets, as well as Mercury itself.”

Artist’s concept of a collision between two large astronomical objects, which may have been how K2-229b formed. Credit: NASA/JPL-Caltech

Given its dense, metallic nature, it is something of a mystery of how this planet formed. One theory is that the planet’s atmosphere could have been eroded by intense stellar wind and flares, given that the planet is so close to its star. Another possibility is that it was formed from a huge impact between two giant bodies billions of years ago – similar to the theory of how the Moon formed after Earth collided with a Mars-sized body (named Theia).

As with many recent discoveries, this latest exoplanet is giving astronomers the opportunity to see just what is possible. By studying how them, we are able to learn more about how the Solar System formed and evolved. Given the similarities between K2-229b and Mercury, the study of this exoplanet could teach us much about how Mercury became a dense, metallic planet that orbits closely to our Sun.

Further Reading: Warwick