The Times Australia
The Times World News

.

Are there any planets outside of our solar system?

  • Written by Jean-Luc Margot, Professor of Earth, Planetary, and Space Sciences, University of California, Los Angeles
Are there any planets outside of our solar system? Curious Kids[1] is a series for children of all ages. If you have a question you’d like an expert to answer, send it to curiouskidsus@theconversation.com[2]. Are there any planets outside of our solar system? - Eli W., age 8, Baton Rouge, Louisiana This is a question that human beings have wondered about for thousands of years. Here’s how the ancient Greek mathematician Metrodorus[3] (400-350 B.C.) put it: A universe where Earth is “the only world,” he said, is about as believable as a “large field containing a single stalk.” About 2,000 years later, in the 16th century, the Italian philosopher Giordano Bruno[4] suggested something similar. “Countless suns and countless earths” existed elsewhere, he said, all rotating “round their suns in exactly the same way as the planets of our system.” Scientists now know that both Metrodorus and Bruno were essentially correct. Today, astronomers like me[5] are still exploring this question, using new tools. An exoplanet orbiting a red dwarf star. An exoplanet orbiting a red dwarf, a star that is dimmer than our Sun and about half the size. Mark Garlick/Science Photo Library via Getty Images[6] The exoplanets There is now evidence that demonstrates the existence of “exoplanets” – that is, planets orbiting stars other than our Sun. That evidence is based on the discoveries made by the Kepler space telescope[7], launched by NASA in 2009. For four years, the telescope stared continuously at a single region of space within the constellation Cygnus[8]. Looking from Earth, it’s an area that takes up less than 1% of your view of the sky. Are there any planets outside of our solar system? Artist illustration of NASA’s Kepler space telescope. NASA Images[9] How the telescope worked Kepler had 42 cameras on board, similar to the kind of smartphone camera that you use to take pictures. In that one region, the telescope detected more than 150,000 stars. About every half-hour it observed the amount of light radiating from each star. Back here on Earth, a team of Kepler scientists analyzed the data. For most stars, the amount of light stayed pretty much the same. But for about 3,000 stars, the amount of light repeatedly decreased, by small amounts and for several hours. These drops in brightness happened at regular intervals, like clockwork. The drops, astronomers concluded, were caused by a planet orbiting its star, periodically blocking some of the light that Kepler’s cameras would otherwise detect. This event – when a planet passes between a star and its observer – is known as a transit[10]. And that means that in that one speck of space the Kepler telescope found 3,000 planets. NASA Video: Animation of a exoplanet transiting its star.That’s only the beginning Although 3,000 planets sounds like a lot, it’s certain many others within that area remain undetected. That’s because their orbits never blocked the light as seen by Kepler. After all, planetary orbits aren’t all the same; they’re randomly oriented. But because of the number of transits observed by Kepler, and astronomers’ knowledge of geometry, we can make a good guess on the total number of exoplanets out there. And after making those calculations, scientists now think, on average, that every star has at least one planet[11]. This discovery has revolutionized astronomy and our view of the universe. NASA Video: Weird and Wondrous Worlds.100 billion stars, 100 billion planets For instance, our Milky Way galaxy has at least 100 billion stars; that means it has at least 100 billion planets too. But remember: The universe holds up to 2 trillion galaxies. That’s 2,000,000,000,000! And each galaxy contains tens or even hundreds of billions of stars. So the number of planets in the universe is truly astronomical, roughly equivalent to the number of grains of dry sand[12] on every beach on Earth. Some of those planets are gas giants, like Jupiter[13] in our solar system. Others are boiling hot, like Venus[14]. Others may be water worlds[15] or ice planets[16]. And some are Earth-like. In fact, the Kepler team calculated the abundance of Earth-like planets in the “habitable zone,” a sector of space around each star where a world might have moderate temperatures and liquid water. They found approximately 50% of Sun-like stars in the Milky Way[17] host an Earth-like planet in the habitable zone. That adds up to billions of potentially habitable worlds[18] just in our galaxy. NASA/JPL-Caltech Video: What is the “Habitable Zone”?Could life exist elsewhere? Although scientists haven’t found proof yet, many – including me[19] – now think it’s unlikely that Earth is the only planet where life evolved. That would be as surprising as a large field containing a single stalk. When will humans detect life elsewhere? Will it be intelligent life? Will people ever receive a message from another civilization? Today, hundreds of scientists around the world are trying to answer those questions. Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to CuriousKidsUS@theconversation.com[20]. Please tell us your name, age and the city where you live. And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.

References

  1. ^ Curious Kids (theconversation.com)
  2. ^ curiouskidsus@theconversation.com (theconversation.com)
  3. ^ Metrodorus (en.wikipedia.org)
  4. ^ Giordano Bruno (www.britannica.com)
  5. ^ astronomers like me (scholar.google.com)
  6. ^ Mark Garlick/Science Photo Library via Getty Images (www.gettyimages.com)
  7. ^ Kepler space telescope (kidsdiscover.com)
  8. ^ constellation Cygnus (kids.kiddle.co)
  9. ^ NASA Images (exoplanets.nasa.gov)
  10. ^ transit (exoplanets.nasa.gov)
  11. ^ that every star has at least one planet (www.popsci.com)
  12. ^ number of grains of dry sand (www.universetoday.com)
  13. ^ Jupiter (spaceplace.nasa.gov)
  14. ^ Venus (spaceplace.nasa.gov)
  15. ^ water worlds (www.nasa.gov)
  16. ^ ice planets (spaceplace.nasa.gov)
  17. ^ 50% of Sun-like stars in the Milky Way (www.nasa.gov)
  18. ^ billions of potentially habitable worlds (www.space.com)
  19. ^ including me (seti.ucla.edu)
  20. ^ CuriousKidsUS@theconversation.com (theconversation.com)

Read more https://theconversation.com/are-there-any-planets-outside-of-our-solar-system-164062

Times Magazine

Building a Strong Online Presence with Katoomba Web Design

Katoomba web design is more than just creating a website that looks good—it’s about building an online presence that reflects your brand, engages your audience, and drives results. For local businesses in the Blue Mountains, a well-designed website a...

September Sunset Polo

International Polo Tour To Bridge Historic Sport, Life-Changing Philanthropy, and Breath-Taking Beauty On Saturday, September 6th, history will be made as the International Polo Tour (IPT), a sports leader headquartered here in South Florida...

5 Ways Microsoft Fabric Simplifies Your Data Analytics Workflow

In today's data-driven world, businesses are constantly seeking ways to streamline their data analytics processes. The sheer volume and complexity of data can be overwhelming, often leading to bottlenecks and inefficiencies. Enter the innovative da...

7 Questions to Ask Before You Sign IT Support Companies in Sydney

Choosing an IT partner can feel like buying an insurance policy you hope you never need. The right choice keeps your team productive, your data safe, and your budget predictable. The wrong choice shows up as slow tickets, surprise bills, and risky sh...

Choosing the Right Legal Aid Lawyer in Sutherland Shire: Key Considerations

Legal aid services play an essential role in ensuring access to justice for all. For people in the Sutherland Shire who may not have the financial means to pay for private legal assistance, legal aid ensures that everyone has access to representa...

Watercolor vs. Oil vs. Digital: Which Medium Fits Your Pet's Personality?

When it comes to immortalizing your pet’s unique personality in art, choosing the right medium is essential. Each artistic medium, whether watercolor, oil, or digital, has distinct qualities that can bring out the spirit of your furry friend in dif...

The Times Features

NSW has a new fashion sector strategy – but a sustainable industry needs a federally legislated response

The New South Wales government recently announced the launch of the NSW Fashion Sector Strategy, 2025–28[1]. The strategy, developed in partnership with the Australian Fashion ...

From Garden to Gift: Why Roses Make the Perfect Present

Think back to the last time you gave or received flowers. Chances are, roses were part of the bunch, or maybe they were the whole bunch.   Roses tend to leave an impression. Even ...

Do I have insomnia? 5 reasons why you might not

Even a single night of sleep trouble can feel distressing and lonely. You toss and turn, stare at the ceiling, and wonder how you’ll cope tomorrow. No wonder many people star...

Wedding Photography Trends You Need to Know (Before You Regret Your Album)

Your wedding album should be a timeless keepsake, not something you cringe at years later. Trends may come and go, but choosing the right wedding photography approach ensures your ...

Can you say no to your doctor using an AI scribe?

Doctors’ offices were once private. But increasingly, artificial intelligence (AI) scribes (also known as digital scribes) are listening in. These tools can record and trans...

There’s a new vaccine for pneumococcal disease in Australia. Here’s what to know

The Australian government announced last week there’s a new vaccine[1] for pneumococcal disease on the National Immunisation Program for all children. This vaccine replaces pr...