Comet Holmes orbits between Mars and Jupiter. It never comes very close to the Sun. Its position is shown here on October 24, 2007, when it suddenly brightened dramatically.
Click on image for full size
Original Windows to the Universe artwork by Randy Russell using data from NASA/JPL.
News story originally written on October 29, 2007
In late October 2007 Comet Holmes suddenly grew dramatically brighter. In just a few hours between October 23rd and 24th, the comet became nearly 500,000 times brighter! Before that time the comet was extremely dim, having a magnitude of about 17, and could only be seen with large telescopes. After its sudden brightening, it became visible to the naked eye and is about as bright as Polaris (the North Star).
The comet now has a coma (the name of the "atmosphere" that forms around a comet when it heats up and emits gases), giving it the appearance of a fuzzy ball when viewed through even small binoculars or a telescope. The comet is still quite far from the Sun beyond the orbit of Mars, and does not have a noticeable tail.
Astronomers are not quite sure why Comet Holmes has brightened so suddenly. Perhaps some unusual event caused a large amount of ice in the comet's interior to be exposed to the warming effects of the Sun, turning the ice to gas and forming the suddenly large coma.
Comet Holmes was first discovered in 1892 by the British astronomer Edwin Holmes. It orbits the Sun once every 6.9 years, keeping between the orbits of Mars and Jupiter. It is usually very dim because it stays quite far from both Earth and from the Sun, so it is not heated much and therefore doesn't usually emit much gas and dust to form an easily visible tail. It went through a brightening phase around the time of its discovery in 1892 similar to the 2007 outburst. In 1892 it brightened to about magnitude 4 or 5, similar in brightness to some of the dimmer stars visible without a telescope.
The links below provide photos of Comet Holmes and sky charts to help you find it in the sky. It is currently (as of this writing in October 2007) in the constellation Perseus.
Shop Windows to the Universe Science Store!
Our online store
includes issues of NESTA's quarterly journal, The Earth Scientist
, full of classroom activities on different topics in Earth and space science, as well as books
on science education!
You might also be interested in:
How did life evolve on Earth? The answer to this question can help us understand our past and prepare for our future. Although evolution provides credible and reliable answers, polls show that many people turn away from science, seeking other explanations with which they are more comfortable....more
Not long ago, many people thought that comets were a portent that something bad was about to happen to them. Since people did not yet understand about the objects in the solar system and how they moved,...more
What's in a Name: So named because it is the closest star to the celestial north pole. Claim to Fame: It's the famous North Star! (actually a triple star system) Type of Star: Yellow-white Supergiant...more
A comet generally has two tails, not one. Some pictures accurately show this phenomena. One tail is due to the comet's dust particles, the other is due to ionized gas from the comet coma. Dust particles...more
The pinpoints of light that you see in the night sky are stars. Your ability to see the stars depends on their magnitude as seen from Earth. Stars are giant balls of gas in space that shine through the...more
Perseus, the Hero, can be found in the sky during the winter in the Northern Hemisphere. With a little imagination, you can see the image of a man in the stars. He has a sort of triangular body, with...more
In late October 2007 Comet Holmes suddenly grew dramatically brighter. In just a few hours between October 23rd and 24th, the comet became nearly 500,000 times brighter! Before that time the comet was...more
1998 was a very full year when it came to space exploration and history making. In the blast-from-the-past department, John Glenn received another go for a launch aboard Space Shuttle Discovery. After...more