A A A

Vintage space: Venus in 1991

By Oli Usher, on 28 July 2015

On 5 May 1989, the Space Shuttle Atlantis released the Magellan probe into low Earth orbit.

A short while later, Magellan’s rockets fired, sending it towards the sun.

Magellan being deployed from the Space Shuttle Atlantis on 5 May 1990. Photo: NASA (public domain)

Magellan being deployed from the Space Shuttle Atlantis on 5 May 1989. Credit: NASA

Swinging around our star, it arrived at its destination 15 months later: the planet Venus.

Venus is in some respects the most Earth-like planet in the Solar System. It is a similar size to our planet, has a rocky surface and a thick cloudy atmosphere. However, it is much closer to the sun, and thanks to its atmosphere, experiences a powerful greenhouse effect.

The planet Venus, seen by Mariner 10. Credit: NASA (processing by Ricardo Nunes)

The planet Venus, seen by Mariner 10. Credit: NASA (processing by Ricardo Nunes)

Surface temperatures there are well over 400 degrees Celsius, atmospheric pressure is similar to what submersibles experience a kilometre down into Earth’s oceans, and the ‘air’ of Venus’ atmosphere is full of sulphuric acid.

Exploration of Venus’ surface has been in the form of brief snapshots, taken in the few tens of minutes that landers survive the harsh conditions there. All the landers so far have been Soviet; UCL has a number of their photos in its Centre for Planetary Sciences’ image archive (with a selection available online in high resolution).

The surface of Venus seen by the Venera 13 probe. Credit: UCL RPIF

The surface of Venus seen by the Venera 13 probe. Credit: UCL RPIF

Observing Venus from space is less challenging – and less rushed.

Between 1990 and 1994, Magellan was able to study the planet’s surface at leisure from its position high above the atmosphere. Because of the thick clouds, its images had to be produced by radar rather than optical photography, so they are not in colour. But they are extremely sharp.

Here is one of these images, held in UCL’s archives:

magellan-synthetic-aperture-radar

One of Magellan’s radar images of Venus’ surface. (The image is squint in the original!). Credit: UCL RPIF

Most of the highly processed images from Magellan are produced by multiple passes of the spacecraft over the planet’s surface, building up a complete image of the surface. This particular picture, however, is incomplete, revealing how Magellan’s images are put together. The black stripes show the gaps between the strips observed during different orbits of the planet.

Also in UCL’s archives are some of the planning documents NASA produced as part of the mission, including this full map of the planet’s surface:

magellan-planning-chart-cc

Planning chart for the Magellan mission. Click here for labelled image showing the location of the above radar map. Credit: UCL RPIF

 Links

 

 

 

 

Five years of Arctic ice

By Oli Usher, on 21 July 2015

Five_years_ice-thickness_change

Five years of sea ice changes in the Arctic. (Click picture to start animation)

New research from scientists at UCL and the University of Leeds shows an unusually cool summer in the Arctic in 2013 led to a boost in sea ice. The research, carried out with the European Space Agency’s CryoSat-2, gives researchers of the fluctuations in ice between years, and suggests that pack ice in the northern hemisphere is more sensitive to changes in summer melting than it is to winter cooling.

The image above (click to animate it) shows the variation recorded by CryoSat-2 from 2010 to 2014.

Photo credit: ESA/CPOM (free for most uses – see conditions)

Soapbox science: bringing science to the people

By Amy L Edgington, on 22 May 2015

amy-tak4
The planet Mercury is approximately 48 million miles away, but this summer I’m bringing Mercury to the SouthBank!

My name is Amy Edgington, I am a PhD student in the Earth Sciences department here at UCL, and I have been lucky enough to be selected as one of the speakers for Soapbox Science in London on 30 May.

Soapbox Science is a series of public outreach events happening all over the country this summer, promoting female scientists and the incredible work they are doing. It’s a great opportunity to share my research with the general public, answer questions, and engage in exciting debate!

Soapbox Science in London, sponsored by L’Oreal, ZSL, STFC and NERC, will transform the SouthBank into an arena for scientific discussion and learning. The variety of topics on show is massive- so there will definitely be something for everyone!

I will be taking to the soapbox to discuss my PhD research so far, investigating the interior of the planet Mercury. The large uncompressed density of the innermost planet suggests it is highly enriched in metallic iron, however, there are ground based measurements1 that imply a liquid layer remains in its interior.

amy-take3

Even just these two clues start to build an intriguing picture of the structure and dynamics hidden deep beneath Mercury’s cratered surface. As part of the Earth Sciences department here at UCL I use ab initio molecular dynamics to study the behaviour and thermodynamics properties of the materials that might form Mercury’s core, namely liquid iron and liquid iron alloys on the atomic scale.

A better knowledge of these materials may lead to a greater understanding of the interior of the solar systems smallest planet, and hopefully unlock insights into its evolution. I will be discussing all of this and more with the help of some iron bolts and a giant polystyrene Mercury on 30 May, from 2-5pm on the Southbank.

Follow @SoapboxScience and @ES_UCL to keep updated with this event, plus visit  soapscience.org for more information on all the SoapBox Science events this summer, and to read some of the amazing Women in Science blogs.

Related Links:

Not waving

By Kat F Austen, on 19 January 2015

By 2050, London is likely to be severely in drought. The cause is a combination of growing population, the way we use water and pipe it around our cities and towns, and climate change. If we carry on as we are, there will be a deficit amounting to the water use of 2 million people in a short few decades. On the other hand, risks of water related natural disasters are set to increase, particularly the likelihood of large parts of the UK submerging if all Arctic ice melts. It’s the same story around the globe.

We know all this, and yet as a species we are doing little to address the problem. We protest, we raise awareness, but overall we are still heading for a vastly altered world.

This week, I’m exhibiting my sculpture Not Waving at The Crystal in East London, as part of New Atlantis, an immersive theatre production from LAStheatre. Consisting of 100 miniature people atop 3 miniature icebergs in a bath, an urn and a lot of clever electronics, this interactive installation determines the micro-people’s fate dependent on how much we are chattering about #water on Twitter. Tweet enough and they may survive the show, but if there isn’t enough chatter, water is released from the urn above them – they are drenched and doomed.

The icebergs are made of between 3 and 6 litres of water, which takes quite a while to freeze. Preparations for the sculpture began back in late November, when I started making the moulds for the icebergs with the help of prop-maker Ben Palmer. Once the moulds were ready, I brought them to UCL’s Ice Physics lab where the icebergs were frozen over the course of the last 2 months by Ben Lishman, of UCL’s Institute for Risk and Disaster Reduction, who’s also appearing in the show.

Ben Lishman

Next came the electronics – a Raspberry Pi and servo hacked into a water urn. This rig talks to the internet and controls the urn’s tap, releasing water when there has been insufficient tweeting about #water. What’s insufficient? Well, I worked out an average number of tweets per 10 minutes across an evening, and set it at just above that mark – 50 per 10 minutes. This is all connected up to a screen, programmed with the help of Jun Matsushita to look like this:

photo 1Of course, the secret is that the fate of our 100 micro-people is sealed: the urn will empty into the bath at the end of the show. Because it turns out social media chatter doesn’t change our fate – we need to act here in the physical, real world. The one in which the water is wet, the ice is melting, and the little people are struggling to stay dry.

photo 2That’s the reason the drowning is staged in a bath, with a hot-water urn above it, and tweets scrolling on a screen above that. All these activites – heating and processing water, and our endless online activity – they have a carbon footprint. They are all contributing to climate change.

photo 3

Happily, we aren’t at the end of the show yet – and New Atlantis gives the audience the opportunity to learn about how we might deal with water stress in the future – and make decisions within the world of New Atlantis about how we might move forward.

Lots of the details of production are on my blog, and if you’re thinking of doing something similar I’d be very happy to tell you more of what I’ve learned. I also explain a bit more about it in this interview for iScience.

If you’d like to check it out, New Atlantis runs until the 25th January at The Crystal.

Kat Austen is Artist in Residence at UCL Faculty of Mathematical & Physical Sciences

Related links

Fossil crab

By Oli Usher, on 17 November 2014

Fossilised crab. Credit: UCL Geology Collections

Fossilised crab. Credit: UCL Geology Collections

This specimen, from UCL’s Geology Collections, shows a well-preserved fossilised crab. Its legs are largely intact and even the texture of its abdomen can be made out. The claws, however, are missing.

Crabs’ claws are one way to tell male and female specimens apart (males’ claws are generally larger). Interestingly, the shape of a crab’s underside also hints at its sex in most species.

(Any amateur or expert determinations of this crab’s sex are most welcome in the comments below.)

Crabs have existed since the Jurassic period, 145-200 million years ago.

Links

High resolution images

Marvellous maps

By Oli Usher, on 20 October 2014

Part of George Greenough’s 1819 geological map of England & Wales, showing modern-day Cumbria (then Cumberland and Westmoreland)

Part of George Greenough’s 1819 geological map of England & Wales, showing modern-day Cumbria (then Cumberland and Westmoreland)

This picture shows part of George Bellas Greenough’s 1819 geological map of England and Wales – the first to comprehensively map what lies beneath England’s countryside. This page shows the counties of Cumberland and Westmoreland (modern Cumbria).

Greenough was a pioneering geologist of the 19th century who left his collections to UCL when he died in 1855. (His name is commemorated in UCL’s Earth Sciences student society, the Greenough Society.)

Some of Greenough’s maps, along with other historic items from UCL’s Geology Collections, were publicly displayed on Friday as part of Earth Sciences week.

 

Links

High resolution images

 

Mapping the Apollo landing sites

By Oli Usher, on 29 September 2014

Lunar Orbiter Photographic DataApollo 11, which touched down in the Sea of Tranquility on 20 July 1969 was the first manned landing on the Moon. But prior to the human spaceflight project, NASA explored the Moon with robotic probes. One key element of this endeavour was the Lunar Orbiter programme, which included five spacecraft that mapped almost the entire lunar surface in 1966 and 1967. This was in part in order to identify landing sites for Apollo, but the missions also had broader scientific goals.

Shortly before the first manned landing, NASA published a catalogue of all their data from the Lunar Orbiter programme, entitled Lunar Orbiter Photographic Data. This features maps of the entire Moon, with the locations, sizes and shapes of all Lunar Orbiter photos marked on them, along with extensive technical information.

Today, missions like this work entirely online, but in those pre-internet days, the data had to exist in hard copy.

A copy of this book exists in UCL’s planetary science archives, the NASA Regional Planetary Imaging Facility. Among its pages is the mapping of the area Apollo 11 landed in, the Sea of Tranquility (Mare Tranquilitas here). This is located towards the right of this sheet, where the imaging (marked in red) is densest.

Lunar Orbiter V - Sea of Tranquility

Links

High resolution images

 

Close encounters with fear and dread

By Oli Usher, on 8 September 2014

Cover of Phobos: Close Encounter Imaging from the Viking Orbiters

Cover of Phobos: Close Encounter Imaging from the Viking Orbiters

This week’s Picture of the Week comes from UCL’s planetary science archives, and their rich collection of early NASA space images. Many of these are not available anywhere online, and some of them are hidden behind rather unpromising covers (see above).

The Viking missions to Mars, two identical spacecraft launched a few weeks apart in 1975, are well known for making the first successful landings on the surface of the red planet. But the Viking orbiters were important too, mapping the surface of the planet and observing its moons, Phobos (fear) and Deimos (dread).

This NASA book from 1984, entitled Phobos: Close Encounter Imaging from the Viking Orbiters is a comprehensive album of the observations the programme made of Phobos, the larger of the two moons.

This picture shows a typical spread, produced during the flyby of Phobos on May 26, 1977 by Voyager Orbiter 1.

Phobos from Viking 1

Phobos from Viking 1

Although it is the larger of the two moons of Mars, Phobos is still very small, and seems likely to be an asteroid captured by Mars’ gravity, rather than a moon formed at the same time as its parent planet.

A fraction of the size of Earth’s Moon, its gravity is not strong enough to have pulled it into a sphere, leaving the irregularly-shaped object visible here.

A Russian mission to land on Phobos and return a sample to Earth, Fobos-Grunt, malfunctioned shortly after launch in November 2011 and never left Earth orbit.

Links

High resolution image

The oldest rocks on Earth

By Oli Usher, on 31 July 2014

A crystal of zircon (zirconium oxide). Credit: Denniss/Wikimedia Commons (CC-BY-SA 3.0)

A crystal of zircon (zirconium oxide). Credit: Denniss/Wikimedia Commons (CC-BY-SA 3.0)

The Earth is about 4.5 billion years old, but almost everything on its surface is much, much younger. Mountain ranges are formed and erode, oceans rise and fall, and the tectonic plates of our planet’s crust are constantly being subducted and renewed.

But there are still some surprisingly old rocks on the surface of the Earth.

In the Jack Hills region of Australia, geologists have found small crystals of zircon that can be dated to about 4.4 billion years ago – a period in which the young Earth was totally different to how it is now (it even had a partially molten still). These tiny minerals have survived largely unchanged for almost the entire history of the Earth, despite the total renewal of the rest of our planet’s surface in that time.

The Namib Sand Sea, a desert in south-west Africa, is another case in which geologists find surprisingly old minerals: in this case, grains of sand which have been sitting in the desert for over a million years. By comparison, many far more solid-looking features of Northern European landscapes, such as the rugged terrain of the Scottish Highlands, are less than 20,000 years old, having formed in the last glaciation.

In this video, Dr Pieter Vermeesch (UCL Earth Sciences) explains how geologists in the London Geochronology Centre at UCL are able to use cosmic rays from distant supernovae to calculate the age of the sand in the Namib Sand Sea.

Update – 06.08.14 – The Department of Earth Sciences has just published three further videos featuring Pieter Vermeesch talking about geochronology.