Tim Peak Event

The James Webb Space Telescope – why do we need it?

The James Webb Space Telescope (JWST) is the successor to the Hubble Space Telescope and is due to be launched on an Ariane 5 rocket in Spring 2019. The JWST will be the premier space observatory of the next decade, supporting thousands of astronomers worldwide.

The telescope will study every phase in the history of our Universe, ranging from the first luminous glows after the Big Bang, to the formation of solar systems capable of supporting life on planets like Earth, to the evolution of our own Solar System.

JWST is a large infrared telescope with a huge primary mirror that has a diameter of 6.5 meters (see image below). The sunshade, which is the largest structure of JWST – the size of a tennis court, will act as a shield to the deployed primary mirror.

The Successor to Hubble
JWST is designed not as a replacement, but as a successor that will expand on the scientific success of the Hubble Space Telescope. JWST is designed to operate at very low temperatures (around -230° C) and will primarily look at the Universe in the infrared, looking deeper into space to see the earliest stars and galaxies that formed in the Universe and to look deep into nearby dust clouds to study the formation of stars and planets. It is planned that the mission will last around 10 years, where the mission lifetime will depend on the amount of fuel that is used for maintaining the orbit of the spacecraft and instruments.

Following Launch
Thirty minutes after launch JWST will deploy from the Ariane 5 Rocket and will immediately deploy the solar array. In the following days and weeks after launch there will be several trajectory correction manoeuvres followed by the commencement of the major deployment, firstly the sunshield pallets and then the telescope.

During the first couple of months of the mission the four instruments will be turned on with the final instrument MIRI becoming operational. At the end of the third month the first science-quality images will be taken and JWST will complete its initial orbit around L2 (see image below), its home for the next decade.

(The five Lagrangian points for the Sun-Earth system are shown here. An object placed at any one of these 5 points will stay in place relative to the other two. The L2 point, where the JWST will be is 1.5 million km from Earth. Credit: NASA)

JWST has four mission science goals:

1) To search for the first galaxies and stars that formed after the Big Bang, and to learn how they evolved throughout the history of the universe.

2) Determine how galaxies evolved from their formation until the present day looking inside stellar nurseries and at planets forming in dusty disks around young stars.

3) Observe the formation of stars from the first stages to the formation of planetary systems.

4) Measure the physical and chemical properties of planetary systems and investigate the potential for life in those systems.

UK Involvement
The Mid-Infrared Instrument (MIRI) was developed in a collaborative effort between scientists and engineers from ten European countries, led by the UK and the Jet Propulsion Laboratory (JPL), with the support of ESA and NASA. The UK team is made up of a partnership between the Science and Technology Facilities Council (STFC), University of Leicester and Airbus Defence and Space with funding from the UK Space Agency.

In addition to MIRI, University College London’s Mullard Space Science Laboratory is contributing NIRSpec’s on board calibration system and ground support equipment.

Want to know more about the James Webb Space Telescope? Click here

Interesting images: Gaia detects proton storm

The European Space Agency’s Gaia mission has been in orbit since December 2013. Its purpose is to observe more than a thousand million stars in our Galaxy, monitoring each target star about 70 times over a five-year period and precisely charting their positions, distances, movements and brightness.

Although Gaia is not equipped with a dedicated radiation monitor, it can provide information about space weather (and the solar particles and radiation) that it encounters at its unique orbital position, 1.5 million km from Earth towards the Sun.

In September, Gaia unexpectedly detected a large quantity of subatomic particles, called protons, that make up each and every one of us, emitted by a solar flare.

(In this image, captured by Gaia’s Wave Front Sensor – a sort of ‘camera within a camera’ in its main star-sensing instrument – the streaks of ‘snow’ are trails of individual protons. During normal space weather conditions, the image would only include one or two proton trails. The long trail running horizontally across the image indicates a particularly energetic proton. Image Credit: ESA / E. Serpell)

Read the full story here.

ESA Space news: The colour sphere of the Sun

This colourful image, released earlier today as ESA’s Space Science Image of the Week is a chromosphere flash spectrum captured during the total solar eclipse that could be seen across the United States on 21 August 2017.

The image was taken by ESA’s expedition team who monitored the eclipse from Casper, Wyoming (Copyright ESA/M. Castillo-Fraile).

During an eclipse, when the Moon temporarily partially blocks the light from the Sun, astronomers can make unique measurements. This includes looking at and analysing the normally invisible red hue of the chromosphere.

What is the Sun’s chromosphere?
The sun is made up of different layers (see image below)

(Image Credit: NASA)

The chromosphere is a layer in the Sun between about 250 miles (400 km) and 1300 miles (2100 km) above the solar surface. The technical name for the surface of the sun that we can see, where sun spots and solar flares are sometimes visible, is called the photosphere.

The chromosphere sits above the photosphere and emits a reddish glow as super-heated hydrogen burns off. But the red rim can only be seen during a total solar eclipse. At other times, light from the chromosphere is usually too weak to be seen against the brighter photosphere.

Just before and after the eclipse totality, the Sun’s emission can be split into a spectrum of colours, showing the fingerprint of different chemical elements.

(The colour sphere of the Sun. An image of the eclipsed Sun is produced to the left, and the spectrum of each point of the Sun superposed at the right. Credit: ESA/M. Castillo-Fraile)

The strongest emission is due to hydrogen. The bright yellow corresponds to helium, an element only discovered in a flash spectrum captured during the 18 August 1868 total eclipse, although it was then unknown what it was. Nearly three decades later the element was discovered on Earth and helium is now known to be the second most abundant element in the Universe, after hydrogen.

The image was taken by astronomers from the Cesar science educational project based at ESA’s European Space Astronomy Centre near Madrid in Spain. For more eclipse images and technical information visit the Cesar eclipse website.

Read the full article here