The Solar System

Hi Natali, The term "Dwarf Planet" is a definition created by the International Astronomical Union. From their website: A "dwarf planet" is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite. There are currently five recognised dwarf planets, as listed here.

Hi Sophie, check out this page for information about why Pluto is no longer considered a planet: http://museumvictoria.com.au/planetarium/discoverycentre/faqs/why-pluto-is-not-a-planet/

 

Hi Maddie, your first & second questions can be answered by reading the first paragraph of the infosheet above. For your third question, the sun will keep getting hotter and expand, eventually swallowing the inner planets. A great explanation can be found on the ABC's Meet the Neighbours site. There are probably no more planets in our solar system to discover but out in the universe there are billions, which we call exoplanets (extrasolar planets). As for information about the rotation and orbit of all the planets, the answers can be found under each planet's link on the NASA Worldbook site. We hope this helps!

Hi Abraham, in answer to your question from a few weeks ago, good views of the Milky Way can be seen every night of the year at our latitude although it’s always best to be well away from city lights in a dark location to see it well. Overall the best time in the year would be midwinter at around midnight as by then it stretches high overhead from north east to south west horizons showing us the most expanse of the galaxy. Winter is also better than other seasons as the air is usually clearer and more stable when it’s a clear night all of which improves observing whether by naked eye, binoculars or telescope.

Hi Alana,

We have two separate factors in this excellent question but they are not connected. Jupiter’s spin or speed of rotation is simply how fast it turns on its axis (its “day”), and orbital speed is how long it takes to travel around the Sun (its “year”).

Hi Jessica, sorry for the delay. With the new definition for “planet” a body would need to; (1) orbit the Sun (not another body), (2) be massive enough to have formed into a spherical shape, and (3) to have cleared its orbit of other objects. Pluto satisfies the first two requirements but not the third as there are other objects sharing its orbit around the Sun. However, Pluto has the honour to be one of the first in the new class of dwarf planets which are all significant objects telling us much about the early formation of the solar system. The discovery of so many bodies similar to Pluto has opened up a new chapter in our understanding our the solar system.

Gracie, as indicated above the Solar System developed from elements that later made life possible. But there of course may have been forms of life in other solar systems. You can read more about this on the website for NASA’s Exobiology and Evolutionary Biology Program.

Lollypop, you can find out how to research your question by reading our reply to Maddie on 20 November.

Tegan, the Lunar & Planetary Institute has some great ideas for making model solar systems that would be great for demonstrations.

Hi Clyde Primary School, thanks for all of your questions!  If you take a look around the Museum Victoria Discovery Centre page, under the Astronomy link, you will find the answers to many of your questions.  Maybe also look at the NASA website, http://www.nasa.gov/ and try searching particular phrases or keywords on the internet. 

Jayden - 

There are frequently stories about the end of the world.  The next date making its rounds on the internet is 21^st December 2012  Taken from the NASA web site http://www.nasa.gov/topics/earth/features/2012.html is the following:

There is no credible evidence for any of the assertions made in support of unusual events taking place in December 2012.

Another common misconception is that when there is a planetary alignment, calamities occur.  Planetary alignments actually occur about every 50 or 60 years so over the last 4.3 billion years since the Earth formed we are still here. The next big planetary alignment is on September 8^th 2040 when most of the planets will cluster together, this should give spectacular viewing (if you are still around.!)

Hi Connor,

If the star was twenty light years away, we would see the explosion in twenty years time! We will see the light of the explosion but not feel the shock waves as it too far away. Light waves travel faster and further than any other form of waves. So no, you would not die.

Hi Isra,

The first animal in space was a dog named Laika - she was launched into orbit around the Earth in 1957 in the Russian satellite Sputnik II.

Hey JB & Connor, complex question! Basically, it's always hard to predict what will happen in the future. There are so many factors and variables that influence social and technological development. These sites should give a idea of current ideas and plans in space colonisation ...

http://settlement.arc.nasa.gov/

http://science.nationalgeographic.com/science/space/space-exploration/

http://www.solarviews.com/eng/history.htm

http://www.hq.nasa.gov/office/hqlibrary/pathfinders/colony.htm

http://space.oosa.thinkun.net/space-colonisation

Peter - according to the information provided by NASA at http://solarsystem.nasa.gov/planets/profile.cfm?Object=Sun&Display=Facts, the Effective Temperature of the Sun is 5504 °C

Riley - Mercury can't 'burn to ashes' as the surface is essentially rock, and rock doesn't behave this way when it is hot - althought the surface of Mercury is made of exceptionally hot and inhospitable rock dotted with impact craters, it is essentially similar to the moon in many ways. You can learn more at http://museumvictoria.com.au/discoverycentre/infosheets/planets/mercury/

Benn - Pluto wasn't really 'demoted', just reclassified; it probably shouldn't have been classified as a planet in the first place. You can read the full story at http://museumvictoria.com.au/about/mv-news/2006/problem-of-pluto/

Isaac - scientifically there's no direct evidence of life inhabiting any other planets yet, but given the size of the universe and the liklihood of habitable planets, it seems like a reasonable guess that there is life elsewhere in the universe. NASA has its own research department dedicated to searching for evidence of life elsewhere in the universe, called the NASA Astrobiology Institute; you can learn about their research at http://astrobiology.nasa.gov/about-astrobiology/

Hi Jayne,

The Moon appears inverted, or upside down, when viewed from one hemisphere compared to the other. It’s the result of the different angle viewers have from locations south or north or the equator. The effect is to make the sunlit portion appear to increase from the left side of the Moon during the month as seen from Australia (southern hemisphere) while from the right side as seen from America (northern hemisphere).

Hi Robert, this website from NASA addresses the questions and myths that have built up around this fictional planet. 

Hi Vanessa, all employment positions at the Museum are listed on our website. Good Luck.

 

 

Hi Connor, great question! Although it does sound a bit frightening, the earth is constantly being bombarded by meteorites - because the earth's surface is mostly sea, we don't have many of the records of these impacts, but rest assured, they happen costantly. Thankfully, these are all pretty small and pose a low threat, nothing large enough to trigger an extinction.

There is a research unit of NASA that examines 'Near Earth Objects', asteroids,comets and meteorites that have potential to strike the earth. The website is at http://neo.jpl.nasa.gov/; we mention this to assure you that there are many experts monitoring this, and that doesn't appear to be a significant threat from an extinction caused by a large meteorite strike any time soon.

Hi Lachlan, please see our Glossary of Astronomical Terms for your answer about light years.

The declassification of Pluto apparently produced heated debate among astrologers particularly on blogs. It seems that just because it's not a planet anymore doesn't mean that it is not considered significant by the astrological community. Just like for astronomers, Pluto's re/declassification does not detract from its interest and, possibly, only increases that interest.

Hi Milka! It's great that you've got such an interest in astronomy. We'd suggest that you have a look at the other infosheets available on this site (lots of your questions are answered there), and if you'd like to learn more, have a look at Australian Astronomy's "Learning More" page for some fun and useful links!

Achim, the mass of Jupiter is an incredible 318 times that of earth, and is generally calculated to be, in kilograms, 1.9 times 10 to the power of 27!  More info here.

Hi Alan - our Planetarium staff think that the bright star you are seeing is the second brightest star in the night sky - Canopus.  It is low in the south west in the early morning, just before sunrise.

Hi Skye - Whilst we are not affiliated with any Queensland astronomy site in particular, there are several astronomy groups with websites that may interest you! Try the Astronomical Association of Queensland, and the South East Queensland Astronomical Society to begin with.

As can be seen from our Skynotes, http://museumvictoria.com.au/planetarium/discoverycentre/skynotes/skynotes-december-2009/ Mercury can be seen in the evening sky just after the Sun sets in the west. Venus is much too close to the Sun at the moment to really see it, but you may just be able to pick it out in the morning in the east just before sunrise.

Hi Alex - the sun is a significant contributing factor to conditions on each of the planets in our solar system. You can find detailed information about individual planets at this website.

A "light year" is a measurement of distance that corresponds to the distance travelled by light in a year, so if a star is 321 light years from the sun, then that star's light will take 321 years to reach the sun.

Hi Christie,

That does sound confusing - perhaps if you combine the information provided in the three Infosheets on the Solar System, the Sun and Jupiter, the answer might present itself.

If a solution is still not forthcoming, you can log an enquiry with the Discovery Centre and we can check with the museum astronomer.

Space is a pretty big topic but this website is a good place to learn about it. We have lots of great information including sky maps,  moon phases, Skynotes and infosheets. You might also want to visit the Planetarium to see one of our shows. The NASA website also has a vast amount of information on space and should keep you busy for ages!

Hi Janie, Within Australia you could try contacting the CSIRO Astronomy & Space division, or you could even try contacting NASA to see if they hold any material that might be of use.

Hi David, here is a link to the Centre for Stellar and Planetary Astrophysics. The website gives you the names of some of the researchers doing this work. http://www.cspa.monash.edu.au/research/clique.html

Hi Mark, you're probably seeing Venus, which is slightly brighter than Jupiter at the moment, even though Jupiter is as close to Earth as it ever gets (it won't be this close again until 2022). Venus is in the western sky and Jupiter is in the east. Saturn cannot be seen at the moment as it is too close to the sun. Hope this helps.

Jupiter is visible from both the city and the country, although there is much better seeing conditions in the country due to there being less light pollution. Check the Skynotes September 2010 for instructions about where to find Jupiter in the night sky this month.

Hi Rhys, we are in the process of updating the information on the Melbourne Planetarium webpage’s, some information about the Dwarf planets can be found here:http://museumvictoria.com.au/about/mv-news/2008/new-dwarf-planets/ Keep checking the websites for updates.

Hi Josh have a read of our Mars infosheet for information that should help with your research. NASA also has some very good resources that you might want to have a look at also.

Hi Shashank, NASA commenced a mission to Pluto in 2006. The unmanned spacecraft, named New Horizons, will reach its closest point to Pluto in 2015.The spacecraft is fitted with scientific instruments which will enable NASA to study the atmospheres, surfaces, interiors and environments of Pluto and its distant neighbours. You can read more about this mission, and others here.

Hi Marleen, the Planetarium staff believe the star referred to is Canopus, the second brightest star in the night sky.  Sirius, the brightest star in the night sky rises just before dawn, but unlikely to be seen, being too low to the horizon.  The brightest object to be seen in the morning night sky is in fact Jupiter.  This can still be seen high in the northern sky even as the sky lightens and turns blue.

Hi Margaret, the Scienceworks Shop has lots of merchandise that may be of interest to you.  You can contact them on 03 9392 4806.

Hi Pasquale, the planets do indeed rotate around the sun as it says in the article above. The apparent 'movement' of the sun across the sky is actually caused by the rotation of the earth - one rotation equals one earth day. You can find further information and links on our website here and here.

Yes, Emma, Mercury is often visible in the night sky. For up-to-date information about where and when to catch a glimpse of the planet, check out Melbourne Planetarium's monthly Skynotes newsletter.

Hi Peter. Who knows what future technologies will allow in regards to space travel but, at the moment, travel to extra-solar objects such as other galaxies and planets does look a little unlikely! As to the expanding universe and reactions, there is no definitive answer to the expanding and accelerating Universe at this time but some recent hypotheses include theories involving Dark Matter or Dark Energy. Take a look at the information on the Museum website regarding the ‘Big Bang’ and also NASA’s website regarding the ‘Big Bang’ and Dark Energy. 

Hi Jacob,

Earth’s gravity is a direct result of its mass and volume, so even if its orbit changed, its mass would not. So, no, the gravity would not change.

Hope this helps!

Hi Graeme, this is a hoax that's been around for a few years and comes around every July/August. You can find further information about it at the Sydney Observatory blog and the Astronomical Society of South Australia site. For reliable information about the night sky you can go to the Planetarium's monthly Skynotes, the August edition of which should be out soon. You can find further information about Mars on this infosheet.

Hi Ashutosh!

When Planets align when viewed from the Earth we call it a planetary conjunction, and these are not too infrequent.  On the morning of the 3rd December, just before sunrise,  Mercury will be low in the sky, then Venus and higher in the sky will be Saturn.  These will be visible no matter where you are on the Earth.

The planets of our solar system frequently “line up” in one way or another as they orbit the Sun at different speeds and distances from the Sun (inner planets more quickly than outer planets slower).  The alignments as seen from Earth, or from an imaginary viewpoint above the solar system looking down, are interesting but have no effect on us in any observable sense. Gravity of the Sun and of the planets, and the speed of the planets around the Sun, hold the solar system together but the vast distances between the planets means this force is very weak.

An interesting site can be seen at :  http://www.solarsystemscope.com/ (not a Museum Victoria site).

Hi Kev,

You've  raised one of the hottest and controversial topics in cosmology; the multi-verse, branes, the big bang, repeated or cycling of the universe etc.. etc.. The short answer is that astronomers, cosmologists, physicists, and philosophers just don’t know for certain although they are using the best mathematics, rigorous modelling and extensive measurements. As far as travelling between supposed universes is concerned, there are no answers either as we have no certainty whether “borders” exist, how objects might cross over if they do, what mechanism might be involved. It is all very much hypothetical and speculative but grounded in the strongest research possible. It really is “cutting edge” but that’s what makes science and inquiry so exciting!

There is an excellent BBC Horizon documentary from 2010 called “What Happened Before the Big Bang”  it really covers everything you are asking about.