We’ve sent numerous missions into space to study the Sun; past and present solar explorers include ESA’s Proba-2 (PRoject for OnBoard Autonomy 2) and SOHO (SOlar Heliospheric Observatory) probes, NASA’s SDO and STEREO missions (the Solar Dynamics Observatory and Solar Terrestrial Relations Observatory, respectively), and the joint NASA/ESA Ulysses mission. However, most of these spacecraft have focused mainly on the equatorial regions of the Sun, with the notable exception of Ulysses – this probe observed our star at a wide range of latitudes for nearly two decades, until the mission came to an end in 2009.
Despite Ulysses’ insights, this focus on low solar latitudes has left the Sun’s poles relatively unexplored. A lack of imaging data means that scientists must get creative in piecing together pictures of the Sun’s polar regions – as seen here in this artificial image of the solar north pole.
This image extrapolates low-latitude Proba-2 observations of the Sun to reconstruct a view of the star’s pole. While the poles cannot be seen directly, when spacecraft observe the solar atmosphere they gather data on everything along their line of sight, also viewing the atmosphere extending around the disc of the Sun (the apparent glow around the main disc of the Sun, which also extends over the poles). Scientists can use this to infer the appearance of the polar regions. In order to estimate the properties of the solar atmosphere over the poles, they continuously image the main disc of the Sun and take small slivers of data from the outer and upper regions of the star as it rotates, compensating for the fact that the Sun does not rotate at constant speeds at all latitudes. Over time, these small arrays of data can be combined to approximate a view of the pole, as shown in this view. More in-depth information on the process used to create this image can be found here.
Signs of this patchwork approach can be seen in this image, which comprises data from Proba-2’s extreme-ultraviolet SWAP imager. The line across the middle is created due to small changes in the solar atmosphere that occurred over the timeframe of creating this image. This image also shows a bright bulge on the upper-right side of the Sun; this is created by a low-latitude coronal hole rotating around the solar disc. The polar coronal hole region, which can be seen as the dark patch in the centre of the solar disc, is a source of fast solar wind. It is seen here to contain a subtle network of light and dark structures, which may cause variations in solar wind speed.
While such views go a way towards revealing the secrets of the Sun’s poles – such as how waves propagate across our star, and how it may create phenomena such as coronal holes and ejections that go on to influence space weather around the Earth – direct observations of these regions are needed in order to build on past data gathered by Ulysses. ESA’s Solar Orbiter aims to plug this knowledge gap when it launches in 2020. This mission will study the Sun in detail from latitudes high enough to explore its polar regions, also revealing how its magnetic field and particle emissions impact its cosmic environment – including the area of space that we call home.
Representatives from almost 200 countries have gathered in Katowice, Poland for the 24th conference of the Parties (COP24) of the UN Framework Convention on Climate Change. This Copernicus Sentinel-2 image of Katowice was captured on 20 September 2018. The mission is based on a constellation of two identical satellites in the same orbit, 180° apart for optimal coverage and data delivery. Together they cover all Earth’s land surfaces, large islands, inland and coastal waters every five days at the equator. The mission mainly provides information for agricultural and forestry practices and for helping manage food security. Satellite images can be used to determine various plant indices such as leaf area chlorophyll and water content indexes.
One frame in a sequence of images capturing the rotation of the Mercury Planetary Orbiter’s high-gain antenna. The images show the main reflector dish, with the three struts holding the sub-reflector and the antenna feed at the centre of the main reflector dish clearly visible. The side of the Mercury Planetary Orbiter with the low-gain antenna, which protrudes from the side of the module, is also visible, together with some detail of the spacecraft’s multi-layered insulation.
The image was taken on 28 November 2018 by one of the Mercury Transfer Module’s monitoring cameras, M-CAM 3. The image combines two pictures with different exposure times to account for the different brightness levels of different parts of the spacecraft.
The full crew of expedition 57 arrived to the International Space Station on 3 December 2018.
ESA astronaut, Alexander Gerst shared this image on his social media channels saying "Expedition 57 is at full count now. Welcome to the International Space Station, Soyuz MS-11 crew! And congrats to all international partners for preserving continuous human presence on Earth's embassy in space, for more than 18 years now."
Spaceflight affects not only the body but also the mind. Viewing Earth from space day in and out for six months is bound to change a human’s perspective on Earth’s future in our Galaxy.
Living on Earth it is easy to find it rich, vast, and powerful. However, seeing Earth suspended in the void of space with just a thin protective layer shielding all its inhabitants from cosmic radiation, extreme temperatures, and flying projectiles, our mothership suddenly seems so fragile.
This cognitive shift is known as the overview effect that many astronauts report during and after spaceflight. It is an awareness brought on by countless hours of Earth viewing and the photographs taken, like this image captured by ESA astronaut Alexander Gerst from the International Space Station in November 2018, that shows just how thin Earth’s shield, our atmosphere, really is.
It is hard to measure the thickness of our atmosphere, as it becomes thinner with increasing altitude. Though there is no definitive boundary line between it and outer space, atmospheric effects become noticeable when spacecraft reenter Earth at an altitude of 120 km.
Regardless, it is the product of billions of years of biochemical change by the countless organisms able to survive on Earth thanks to this protective layer.
However, should life on Earth continue in its industrial-era tracks, the threats to our planet are internal. Unchecked human consumption of natural resources is causing global temperatures to rise. The resulting change in climate is wreaking havoc on natural habitats and leading to major weather events.
ESA’s Earth observation satellites, along with astronauts from the International Space Station, are witnesses to this global crisis and continue to provide us with data and imagery to inspire action.
This week representatives from almost 200 countries have gathered in Katowice, Poland for the 24th conference of the Parties (COP24) of the United Nations Framework Convention on Climate Change.
One of the most important tasks at the summit is to agree the course of action to implement the 2015 Paris Agreement – and, with the 2°C target now deemed not enough, to coordinate an international effort to halt warming at 1.5°C.
The meeting focuses on a triangle of nature, man and technology, and will investigate how they can be used to reduce climate change and mitigate its effects.
This will take determined and coordinated international effort to help protect our planet. In the meantime, astronauts will continue to share this overview to inspire action.
The first ESA-funded space weather monitoring instrument was launched on 4 December 2018, hitching a ride on South Korea’s new geostationary satellite, GEO-KOMPSAT-2A – the Geostationary Korea Multi-Purpose Satellite-2A.
The satellite, seen in this image, was lofted into orbit on an Ariane rocket from Europe’s Spaceport in Kourou, French Guiana, and will provide meteorological monitoring over the Asia-Pacific region as well as data on space weather.
‘Space weather’ describes the constantly changing conditions in space as a result of the unpredictable behaviour of our active Sun.
This dynamic solar activity changes the space environment, causing variations in magnetic and electric fields, and levels of high-energy particles and radiation around our planet. Such changes can cause impair satellites, disturb telecommunication and satellite navigation, and damage with crucial infrastructure on Earth, such as power grids.
ESA’s Service Oriented Spacecraft Magnetometer (SOSMAG) instrument has four tiny sensors that will measure Earth’s magnetic field and provide data on how space weather affects it.
The SOSMAG kit is designed ultimately to be mounted on a variety of different spacecraft, in an array of orbits, which together will give a fuller picture of Earth’s space weather environment. These ‘hosted payloads’ boost efficiency and reduce cost, while providing critical data to be fed into ESA’s Space Weather Services Network.
Find out more about the network, ESA’s future Distributed Space Weather Sensor System, and the upcoming Lagrange mission to monitor the Sun, all part of the Agency’s plan to monitor hazards in space and one day to mitigate them.
The SOSMAG instrument is funded by ESA’s Space Situational Awareness programme, and was built by an industrial consortium consisting of the Austrian Academy of Sciences, the Space Research Institute (IWF), Magson GmbH, the Institut für Geophysik und Extraterrestrische Physik of TU Braunschweig and the Blackett Laboratory of Imperial College London (ICL).
The Copernicus Sentinel-2 mission takes us over the Chachani mountain in Peru. Standing at over 6000 m, Chachani is the tallest of the mountains near the Peruvian city of Arequipa. The outskirts of the city and part of the airport runway are just visible in the centre bottom of the image. The city is home to around 900 000 people and is renowned for its dramatic cityscape, surrounded by three volcanoes. Chachani is shown in the centre of the image.
Arequipa is also known as la Ciudad Blanca or the White City thanks to the prevalence of baroque buildings carved from white volcanic sillar stone in its centre. The volcanoes, overlooking the city, naturally form an important part of the city’s identity.
Heavy shades of red, showing vegetated areas, dominate this false-colour image. The varying tones represent different vegetation types, at different stages in the annual vegetation cycle. The near-infrared channel of Copernicus Sentinel-2 has been used to achieve this false-colour effect. A number of crops are grown in this area, including maize, asparagus and hot peppers (rocotos), which feature in many local dishes, such as the region’s signature dish of rocoto relleno.
In the centre-right of the image we can see a body of water called Aguada Blanca. This is part of a protected natural area, covering 360 000 hectares. Llamas and alpacas live here, as well as flamingos which have made the surrounding lagoons and wetlands of the Andean plains their home. Wool trade is a huge industry for the region, with artisan crafts also booming in recent years.
Sentinel-2 is a two-satellite mission to supply the coverage and data delivery needed for Europe’s Copernicus environmental monitoring programme. Sentinel-2’s main instrument has 13 spectral bands, and is designed to provide images that can be used to distinguish different types of vegetation and monitor plant growth.
This image, which was captured on 14 July 2017, is also featured on the Earth from Space video programme.
ESA astronaut Alexander Gerst captured this image of the Earth and the Moon from the International Space Station on shared it on his social media channels saying: "The toughest thing for me in space is knowing that only a few humans will ever see our planet like this. It will be essential for our species to eventually to change that."
This image, from the NASA/ESA Hubble Space Telescope’s Advanced Camera for Surveys (ACS), reveals thousands of globular clusters lying at the core of a galaxy cluster. It was created by a Hubble survey that drew on data from three of the telescope’s separate observing programmes to explore the centre of the Coma cluster, a huge gathering of over 1000 galaxies, about 320 million light-years away, all bound together by gravity.
Astronomers spotted over 22 000 globular clusters, some of which had formed a bridge connecting a pair of well-known interacting galaxies (NGC 4889 and NGC 4874). A globular cluster is a spherical group of stars that usually orbits a galaxy as a self-contained satellite. However, the globular clusters studied here are of a different type, intracluster globular clusters. Specifically, these are globular clusters that are not bound to an individual galaxy, but to a galaxy cluster — in this case, Coma.
While globular clusters orbiting our Milky Way reveal themselves as sparkling spherical assemblies of densely packed stars, at the distance of the Comla cluster, they only appear as tiny dots of light, even to Hubble's advanced vision. However, a characteristic feature of globular clusters is their colour; since the stars in any given cluster all formed at around the same time and from the same “stuff”, they usually have a consistent colour. In this way, the astronomers were able to identify the clusters — and rule out background galaxies lying in the same region of sky — by analysing their colour and size, painting a beautiful family portrait of Coma and its clusters.
With the help of the identified globular clusters astronomers can map the distribution of matter and — even more important — of dark matter in the Coma cluster. The Coma Cluster was one of the first places where observed gravitational anomalies indicated the existence of dark matter.
Week in images
3 - 7 December 2018