Posts Tagged ‘comet’

2015: The Year of Dwarf Planets and Small Solar System Bodies

We’re currently living through a very exciting time in space exploration, with a small armada of robot space probes visiting previously unexplored corners of our solar system. Here’s just a few of the amazing discoveries we’ve made in the past few weeks.

New Horizons

New Horizons

This year sees us make close encounters with two of the largest dwarf planets, as New Horizons flies past Pluto for the first time, and Dawn continues to orbit the giant asteroid Ceres. All this as the Philae Lander continues to try to make contact with us from the surface of Comet 67P/Churyumov-Gerasimenko as its parent spacecraft Rosetta follows the comet around the Sun.

Each of these missions is very exciting in its own right, but to have all three happening at once is incredible.

Rosetta and Philae Latest

The Rosetta Orbiter arrived at Comet 67P/Churyumov-Gerasimenko in August last year, and the Philae lander descended onto the comet’s surface in November, carrying out its science mission for 60 hours before its batteries died. Rosetta has continued to produce great science since then; its latest scoop was the discovery of what appear to be sink-holes on the comet’s surface.

Sink Holes on Comet 67P

Sink Holes on Comet 67P

All this while Philae tries to make contact with us, and Comet 67P begins the outgassing that will eventually form its tail as the comet makes its closest approach to the Sun on 12 August 2015.

Comet 67P/Churyumov-Gerasimenko begins outgassing

Comet 67P/Churyumov-Gerasimenko begins outgassing

Dawn Latest

The Dawn spacecraft arrived at Ceres in March 2015, after having spent over a year orbiting the smaller asteroid Vesta. Ceres is the largest of the asteroids, so large in fact that it’s considered a dwarf planet, its gravity having pulled it into a spherical shape.

More and more mysteries are arising as a result of Dawn’s asteroid mission including: what are these bright patches inside craters on Ceres’ surface?

Bright spots in the surface of the Dwarf Planet Ceres

Bright spots in the surface of the Dwarf Planet Ceres

and: what’s a mountain doing on an asteroid?

A mountain on an asteroid

A mountain on an asteroid

New Horizons Latest

Stay tuned for even better images of Pluto as New Horizons speeds towards its 14 July flyby at close to 60000kph. For now the best images we have of Pluto and its moon Charon are from New Horizons’ Long-Range Reconnaissance Imager, which shows features on the surface of the distant Dwarf Planet, which we’ll see in better detail in the next couple of weeks.

Pluto and Charon, real colour

Pluto and Charon, real colour

Other Missions

This is on top of all of the other missions going on up in space right now: Cassini continues to send back breath-taking images and data from the ringed planet Saturn and its moons; no fewer than five spacecraft are currently in orbit around Mars – NASA’s 2001 Mars Odyssey, , Mars Reconnaissance Orbiter, and MAVEN, ESA’s Mars Express, and India’s Mangalyaan – while two intrepid rovers – Opportunity and Curiosity – explore Mars’ surface; and our own Moon is orbited by the Lunar Reconnaissance Orbiter.

We’ll add to this over the next few years, as the Juno probe reaches Jupiter in summer 2016, and as the Japanese mission Hayabusa 2 enters into orbit around an asteroid in 2018 and returns a sample to Earth on 2020.

A New Meteor Shower for 2014: The Camelopardalids

January 9, 2014 Leave a comment

UPDATE: See below

This year sees a brand new meteor shower possibly gracing our night skies, on 24 May 2014.

Meteor showers occur when the Earth passes through a cloud of dust left behind by a comet. These clouds hang in space in the same place, and so meteor showers occur at the same time every year as the Earth revisits them.

But every so often a new comet comes along and creates a cloud of dust where none existed before. In the case of this anticipated shower the comet that left the cloud behind goes by the name of 209P/Linear. It was discovered in 2004 and passed near the sun in 2009, and will do so again this year in early May.

Current predictions are that the Earth will pass through the cloud of dust left by 209P/Linear on 24 May 2014. Quite how many shooting stars will be visible is unknown, but given that this is a fresh cloud of dust that hasn’t been “used up” before in previous meteor showers, we might expect a good display.

Stargazers in North America are probably best suited to see it, but in the UK it’s still worth looking out for. More accurate information regarding timings will become available nearer the time, but regardless of when exactly the Earth passes through the dust stargazers in the UK will have to wait until the sky is dark. It never gets truly dark in the UK in late May except in the south, and the Channel Islands, but the best time is between 0000 and 0200.

And where to look in the sky? As with all meteor showers it doesn’t matter where you look; the shooting stars streak across the sky in all directions. However if you trace the trails back they will all converge at the same part of the sky, called the radiant. Meteor showers are named after their radiants (e.g. the Perseids emerge from Perseus, and the Geminids from Gemini) and this new shower will appear to emanate from the dim constellation of Camelopardalis*, so they’ll be known as the Camelopardalids! Just flows off the tongue…

* Camelopard comes from the romanised Greek words for “camel” and “leopard”, and is the name for a giraffe, which the Greeks thought were part camel, part leopard!

UPDATE: The International Meteor Organisation repeats the need for caution in predicting how good this meteor shower might be:

[M]uch is unknown about this comet, including its dust productivity and even its precise orbit. Consequently, while tentative proposals have been made that ZHRs at best could reach 100+, perhaps up to storm proportions… these are far from certain. The strongest activity could be short lived too, lasting perhaps between a few minutes to a fraction of an hour only. In addition, the number of dust trails involved means there may be more than one peak, and that others could happen outside the “key hour” period, so observers at suitable locations are urged to be vigilant for as long as possible to either side of the predicted event to record whatever takes place. Remember, there are no guarantees in meteor astronomy!

They suggest that independent calculations show that the peak of activity (which might be very narrow, see above) will fall some time around 0700-0740UT (0800-0840BST) Saturday 24 May which obviously means that UK observers will miss the peak (US meteorwatchers will be perfectly placed).

However it is still worthwhile keeping an eye out during the darkest part of the night on the nights of 23/24 and 24/25 May in case there are multiple peaks, or the main peak is broad.

We just don’t know yet what is going to happen with this meteor shower: it might fizzle out to nothing, or it might reach storm levels, meaning hundreds of shooting stars per hour. Good luck!

Comet ISON Finally A Naked-Eye Object

November 15, 2013 Leave a comment

Yesterday Comet ISON (C/2012 S1) brightened suddenly, meaning that it’s now visible to the naked eye – just.

Comet ISON,  imaged by Nick Howes, Ernesto Guido and Martino Nicolini

Comet ISON, imaged by Nick Howes, Ernesto Guido and Martino Nicolini

According to astronomer John Bortle Comet ISON brightened from magnitude +8.5 on Monday and +7.3 on Wednesday,  to +5.4 on Thursday, meaning that it is now visible to stargazers without the aid of binoculars or telescopes – although those devices will help!

You’ll have to be determined to see it, as it rises in the east just before dawn, so an early start is required. At the moment it’s not spectacular, although some astronomers are still holding out hope that it might become the Comet of the Century as was predicted earlier this year. We’ll need to wait and see whether it continues to dramatically brighten. If it does then it may be visible high in the night sky in December.

How Best to See Comet ISON

Here are three simple steps you can take to maximise you chances of seeing this comet.

1. Find somewhere dark with a clear eastern horizon

Although it is now a naked-eye object, any light pollution in the sky will make it next to impossible to see, so head to your local dark sky site. If you don’t know how to find one then have a look at this light pollution map of the UK to give you an idea. In general you want to make sure that any nearby town or city is behind you, so head to the east of any populated are. You’ll need a flat horizon too – east coast is ideal – as hills and trees will block your view. At the moment the comet is still low in the sky when twilight brightens the sky making it impossible to see.

2. Keep an eye on the weather forecast

There’s no point heading out if it’s cloudy towards the east, but just because it’s raining when you go to bed doesn’t mean that it will still be raining at 6am. Check local weather forecasts for predicted cloud cover before dawn.

3. Find Mercury and Spica

The planet Mercury rises around 6am, and at that point the star Spica, in the constellation of Virgo, will be only a few degrees above the horizon. Comet ISON lies above and to the right of, approx. 10° higher than Mercury in the sky. Here’s a simple finder chart for approx. 6am.


Comet ISON marked with a red cross, approx. ESE in the pre-dawn sky mid November. Image via Stellarium

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