You never know what hidden treasures can be uncovered in the archives.

And this was certainly the case at Carnegie Observatories’ collection when research for an article led to the unexpected discovery of a 1917 glass plate showing the first-ever evidence of a planetary system beyond our own Sun.

It all started last year when UCL astrophysicist Dr Jay Farihi contacted Carnegie Observatories’ Director, John Mulchaey, whilst researching an article on planetary systems surrounding white dwarf stars. Farihi was searching for a glass plate that contained a stellar spectrum of van Maanen’s star – a white dwarf discovered by Dutch-American astronomer Adriaan van Maanen.

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Last night saw both a supermoon (the Moon’s closest approach to Earth, in which it appears about 14% bigger than it does at its most distant), and a lunar eclipse, in which the full Moon passes through the Earth’s shadow.

During a lunar eclipse, the disc of the Moon progressively goes from bright white to a deep red: when in the Earth’s shadow, the only light illuminating its surface is the light that is bent through Earth’s atmosphere. This light – effectively, the light of all the sunrises and sunsets on Earth – is red because blue light is scattered in Earth’s atmosphere.

This sequence of photos was produced by Theo Schlichter, Computing and Instrumentation Officer at UCL’s observatory, using a Canon EOS450D camera and a 200mm lens. The composite was produced by Dr Steve Fossey.

This tiny device, developed by researchers at the London Centre for Nanotechnology, could soon help carry out difficult medical diagnoses.

The tiny rods, or ‘cantilevers’, are coated with molecules similar to those in our cells, which have been made sensitive to various diseases. In their work, the team have successfully made coatings which react with molecules that are part of HIV, the antibiotic Vancomycin, and blood anti-clotting factors (for haemophilia).

When in the presence of one of these molecules, the cantilever bends (as seen above), revealing the diagnosis.

• Read more about the research

The blurred, faint, orange speck at the centre of this image may look unremarkable, but it is the most distant galaxy ever to have been confirmed by scientists. Called EGSY8p7, the galaxy was identified by UCL PhD student Guido Roberts-Borsani in the Hubble image above, based on its unusually reddened colour profile.

Followup observations using the WM Keck observatory by a team including Roberts-Borsani and UCL astrophysicist Richard Ellis have confirmed the find. Splitting the light into its component colours, the spectrograph at the observatory showed that the galaxy’s spectrum was shifted far towards the red end of the spectrum by the expansion of the cosmos. This ‘redshift’ is an unmistakeable sign of an extremely distant object.

It is at a redshift of 8.68, meaning we see it as it was when the Universe was only about 4% of its current age. Its light has been travelling for over 13 billion years on its long journey to us.

Read more about the research.

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.

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.

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).

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:

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:

 Links

• Centre for Planetary Sciences
• UCL Regional Planetary Image Facility
• Snapshots from Space History (online exhibition of images from the Centre for Planetary Sciences)
• UCL Physics & Astronomy
• UCL Earth Sciences
• UCL Museums & Collections

 

 

 

 

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)

Positronium is an exotic atom made up of an electron and a positron in orbit around each other. Positrons are the antimatter equivalent of electrons, so these particles are highly unstable composite particles made up of both matter and antimatter.

Because of this, positronium atoms only last a few nanoseconds before the matter and antimatter annihilate each other.

Despite their short lives, these peculiar particles have interesting features – including being able to form compounds despite not actually being an element.

UCL is home to the only positronium beam in the world. In this device, positrons created by a radioactive source pass through a chamber of hydrogen gas, where they pick up electrons, before being guided towards a target.

Standing by the Positronium Beam in this photo are UCL PhD students Andrea Loretti (left) and Sam Fayer (right), both from the Department of Physics & Astronomy.

High resolution images

• High resolution photos of UCL’s Positronium Beam are available on Flickr

Links

• UCL Physics & Astronomy
• UCL Positronium group

 

The Cassini probe launched in October 1997 and arrived in the Saturn system in July 2004. Its Huygens lander touched down on Titan, Saturn’s largest moon, in December 2004. The photo above shows the spacecraft shortly before launch.

More than a decade on, the probe is still sending back data, teaching us about Saturn and its moons.

One of the instruments on board, the Cassini Plasma Spectrometer (CAPS) was designed in part by Prof Andrew Coates at UCL’s Mullard Space Science Laboratory. This week, he has published new research based on data from his instrument.

He has found that the interaction between the Sun, magnetic field lines and the atmosphere of Titan – Saturn’s oddly Earth-like moon – behaves similarly to what we observe here on Earth.

• Read more about the research

After two years of repairs and upgrades, the Large Hadron Collider (LHC) is back in operation – and UCL scientists are at the heart of the action. Engineers at CERN confirmed today that the beams of protons that circle in the 27km tunnel near Geneva are stable, and scientific data is once again being collected.

UCL scientists have been closely involved in the design, construction and operation of ATLAS, one of the giant detectors that track the high-energy particle collisions in the LHC, so this is an important milestone for the university’s High Energy Physics group.

Until now, the LHC has not been operating at full power. The faults that led to its shutdown shortly after it was inaugurated in 2008 meant that it could only be used to accelerate particles to around half the energy it was designed for.

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Einstein’s equation E=mc² states that energy and matter are interchangeable.

Atom bombs, famously, create vast amounts of energy by destroying small amounts of matter.

Particle accelerators like the LHC do the opposite, pumping vast amounts of energy into tiny particles, making them move at close to the speed of light. When they collide together, some of that energy is converted into extra matter, in the form of new particles flung out from the site of the collision. The greater that energy, the heavier the particles that can be generated.

Physicists describe the world around us using the ‘standard model’ of particle physics, a set of a handful of particles which can explain the properties and makeup of all the matter and energy we see around us.

The last of those particles to be detected in the lab was the Higgs boson, discovered at CERN in 2012 shortly before the upgrade began.

This doesn’t mean there is nothing left to discover, though. Scientists, including CERN’s director, have begun speaking of a tantalising ‘new physics’ – whole new uncharted areas of science that are currently totally unknown, but which might be explored with higher-energy collisions and heavier particles generated.

One of these areas could be a solution to the riddle of dark matter.

Dark matter has been detected in distant galaxies, thanks to its gravitational effects, but astronomers have determined that it cannot be made of any of the particles described in the standard model.

ATLAS, the building-sized instrument that UCL participates in, played a key role in the Higgs boson discovery, and will play a starring role in the future work of the LHC, and could help explain how dark matter relates to the standard model of particle physics.

* * *

The LHC consists of two 27km-long pipes that use powerful magnets to accelerate beams of protons in opposite directions.

Inside ATLAS, the two beams are brought together on a collision course. The beams are not continuous: the protons come in pulses (“bunches”) about 10cm long and the width of a human hair, each containing around a hundred billion particles. When these bunches cross each other, protons collide and new particles cascade out through the concentric rings of detectors that make up the ATLAS experiment.

Scientists can then trace the path that the particles took – and determine their energy, mass and electrical charges. And from those, they can infer the process that take places in each proton-proton collision.

During the two-year LHC shutdown, the ATLAS scientists also made several improvements to their detector, most notably with the installation of an extra ring of detectors close to the beam pipe, making it more precise than ever before, and part of the team’s work now that the LHC is running again is to ensure that this is all properly calibrated and working as expected.

When it runs at full capacity, ATLAS detects 40 million particle collisions every second, far more than could ever be studied.

Part of the challenge is to discard the unimportant data so that scientists can focus on what’s important. One of the major contributions UCL scientists have made to ATLAS is to the design and operation of the hardware and software algorithms used to discard trivial events in real time and select only the interesting ones – reducing 40 million collisions per second down to a far more manageable 1,000 that are recorded offline.

Another challenge is the simple matter of timing and synchronisation.

With millions of events per second, and everything moving at close to the speed of light, untangling the data from different collisions is challenging. ATLAS is still detecting particles ejected by one collision while another is already taking place.

UCL scientists played key roles in developing the electronics that ensure that the data is accurately recorded and readouts from the different components of ATLAS are all kept properly synchronised.

* * *

So what’s next for the LHC?

It’s very hard to say – and that’s what is so exciting about particle physics today.

The standard model is complete. There could be a radical departure, revealing areas of physics never explained before.

Equally, there might just be further confirmation of the dramatic discoveries of the past few decades, giving more precision and certainty to the standard model.

In either case, there is now a chance to explore physics without the constraint of theoretical preconceptions – an unusual and liberating place for a physicist to be.

With thanks to Prof Nikos Konstantinidis for help with this article

 

 

 

 

This photo shows a specialised refrigerator, used for cooling objects to within a fraction of absolute zero, located in the Physics building on UCL’s main campus.

When in operation, the refrigerator is entirely enclosed in a sealed and insulated housing, which has been removed here for maintenance.

As with a household fridge, the temperature drops as you go down – with the highest of the four shelves being at a temperature of about 50 Kelvins (-223 Celsius) and the bottom one at just 0.03 K (-273 C).

The refrigerator is used to cool small objects, such as transistors, down to levels where thermal effects (such as the vibration of the atoms in them) are eliminated, allowing quantum effects to be observed.

Samples can be raised or lowered through each shelf via a circular hole in the centre of the refrigerator.

The refrigerator is cooled by a mixture of liquid Helium-3 and Helium-4. The lowest shelf of this refrigerator has a strong claim to being the coldest place in London (alongside a handful of similar facilities at other London universities).

High resolution images

• High resolution images of the equipment are available on Flickr

Related links

• UCL Physics & Astronomy
• UCL Quantum