‘Demon’ asteroid the size of the Eiffel Tower to zoom past Earth Friday


Apophis the asteroid will return in 2029.

This 3D rendering shows what asteroid Apophis might look like as it passes near the Earth. (Image credit: Stephane Masclaux/Shutterstock)

An asteroid the size of the Eiffel Tower will zip past Earth Friday (March 5) and be out of our planetary neighborhood until 2029.

The space rock, dubbed Apophis (an ancient Egyptian demon), was first spotted in 2004 and won’t pose any danger to Earth during this week’s flyby; it will travel past the planet at a little more than 40 times the distance from Earth to the moon. But scientists are using this week as a dress rehearsal for the asteroid’s next pass, on April 13, 2029, when Apophis will get as close to Earth as some of the highest-orbit satellites.

Related: Top 10 ways to destroy Earth

“Apophis in 2029 is going to be a really incredible observing opportunity for us,” Marina Brozović, a radar scientist at NASA’s Jet Propulsion Laboratory in California, told Live Science’s sister site Space.com. “But before we get to 2029, we are preparing.”

A brief flyby

Apophis is 1,120 feet (340-meter-wide) wide and made of rock, iron and nickel. It is probably shaped roughly like a peanut, though astronomers will have a better idea of its form when it passes by Earth this week, according to NASA.

The asteroid takes a full orbit around the sun about every 11 months. On March 5, it will come within 10,471,577 miles (16,852,369 km) of Earth at 8:15 p.m. EST (0115 GMT on March 6). That’s too far to be seen with the naked eye, but scientists will use planetary radar to image Apophis as it flies by using NASA’s Goldstone Deep Space Communications Complex in California and the Green Bank Telescope in West Virginia. They hope to determine the asteroid’s shape and learn more about the way it rotates.

“We know Apophis is in a very complicated spin state, it’s sort of spinning and tumbling at the same time,” Richard Binzel, a planetary scientist at the Massachusetts Institute of Technology, told Space.com.

An animation shows Apophis’ 2029 path compared to the swarm of satellites orbiting Earth. (Image credit: NASA/JPL-Caltech)

This planetary radar study will provide researchers a baseline for the much closer fly-by in 2029, when Apophis will get as close as 19,800 miles (31,900 kilometers) to Earth. That’s close enough that Earth’s gravity might change the shape of the asteroid or scatter the boulders on its surface. How and if the asteroid changes as it flies by will help reveal details about the asteroid’s inner structure, Binzel said.

At its closest approach in 2029, Apophis will be briefly visible to the naked eye over western Australia, growing as bright as the stars in the Big Dipper. It will be closest to Earth at 6 p.m. EDT on April 13, 2029, when it will be over the Atlantic — an ocean it will cross in only an hour. The asteroid will cross over the United States by 7 p.m. EDT.

Apophis is named after an ancient Egyptian demon who personified chaos and evil, largely because astronomers initially calculated that there was a 3% chance the asteroid could impact Earth on its 2029 flyby. They’ve now shown that the asteroid won’t collide with Earth in 2029, nor on its next pass in 2036. There’s still a slight chance that the asteroid could hit Earth in 2068, but the 2021 and 2029 flybys should give astronomers more information with which to calculate Apophis’ future.

Originally published on Live Science.
By Stephanie Pappas – Live Science Contributor

Editor’s note: This article was updated to correct how close Apophis will get to Earth during its flyby.

5116: Scientists prepare for their last good look at asteroid Apophis before 2029 flyby

Chaos is coming.

An animation shows Apophis’ 2029 path compared to the swarm of satellites orbiting Earth. (Image: © NASA/JPL-Caltech)

On March 5, wave hello to the most infamous asteroid that won’t slam into Earth in 2029. Scientists sure will.

Astronomers first spotted the space rock now known as Apophis in 2004. It’s precisely the sort of object that most humans probably want to know about: It’s awfully big and occasionally comes uncomfortably close to Earth. April 13, 2029, is one such occasion, when Apophis will skim so close to Earth that it will pass through the realm of particularly high-altitude satellites.

(It will not hit Earth. Do not panic. Carry on.)

Scientists are excited. They’ve calculated just how rarely an object this large passes this close to Earth. “This something that occurs about once every 1,000 years, so obviously, it is generating a lot of interest,” Marina Brozović, a radar scientist at NASA’s Jet Propulsion Laboratory in California, told Space.com.

Related: Huge asteroid Apophis flies by Earth on Friday the 13th in 2029, a lucky day for scientists

The March flyby won’t be nearly as stunning as the 2029 close approach; Apophis will come only one-tenth of the average distance between the Earth and the sun, more than 40 times as distant as the moon is from Earth. But scientists have big goals for Apophis’ 2029 flyby, and in order to get the most out of that opportunity, they need to know as much as possible about the space rock.

And next month is their last real chance to study Apophis before the big day.

“Apophis in 2029 is going to be a really incredibly observing opportunity for us,” Brozović said. “But before we get to 2029, we are preparing.”

Meet Apophis

Like all near-Earth asteroids, Apophis has been rattling around the inner solar system for millennia, unnoticed by humans. Scientists believe it is more than 1,000 feet (300 meters) wide, around the height of the Eiffel Tower. It’s a mix of rock and metal, according to NASA, and may be shaped a bit like a peanut, two uneven lumps smooshed together.

Astronomers spotted Apophis for the first time in 2004. The asteroid’s discovery is a perfect example of planetary defense, the task dedicated to spotting asteroids around Earth, tracing their precise orbits, and determining whether they pose any risk of hitting Earth. Forewarned is forearmed, so the theory goes, and scientists hope that if they can identify a large future impactor with enough warning, humans can find a way to defend themselves.

Related: Defending Earth against dangerous asteroids: Q&A with NASA’s Lindley Johnson

And for a brief moment, Apophis seemed to run nearly 3% odds of colliding with Earth on April 13, 2029. (Even the best observations have some uncertainty, and the farther ahead in time an orbit is plotted, the more that uncertainty piles up.) That early concern inspired its name, which refers to an Egyptian “demon serpent who personified evil and chaos,” as NASA puts it.

Some of Apophis’ flybys are perfectly mundane, others quite close. But more precise observations pushed any collision fears first to 2036, then to 2068, when scientists can’t quite positively rule out a collision yet.

If Apophis and Earth ever do collide, hope you aren’t around to see the day. Two asteroids of note have hit Earth in the past century or so. One flattened the Siberian forests of Tunguska in 1908, the other shattered in the skies above Chelyabinsk, Russia, in 2013.

They’re nothing compared to Apophis. “Apophis is 300 times more massive than Tunguska, 5,000 times more massive than Chelyabinsk, so this is an object that certainly gets your attention,” Richard Binzel, a planetary scientist at the Massachusetts Institute of Technology, told Space.com.

A natural experiment

Right now, Apophis is minding its own business like thousands of other pieces of cosmic rubble, trekking around the sun every 323.6 Earth days. Hurtling through space, the asteroid’s existence is utterly uneventful.

That will change.

Nine or so more loops around the sun for Apophis and eight more for Earth will bring the objects just within about 19,800 miles (31,900 kilometers). Scientists know that Apophis will not hit Earth this time. But depending on precisely how the two rocks whiz past each other, Apophis may never look the same.

The same gravity that keeps our mundane lives anchored to Earth’s surface will tug at Apophis throughout the close encounter. Scientists think there’s a chance Earth’s gravity will be strong enough to scatter boulders on the surface of Apophis, or perhaps even stretch the asteroid, as if it were saltwater taffy instead of rock.

How dramatic the stretch will be depends on a host of factors. First, the precise shape of Apophis. Then, its orientation during the flyby: If a broad side faces Earth, each patch feels less gravity; if a narrow head does, the asteroid is set up for a game of tug-of-war. Then, what’s inside: Solid, dense rock would resist Earth’s gravity more, a loose cluster of smaller boulders would give more.

Some of those characteristics scientists can study from Earth. But the interior of Apophis is impenetrable at a distance — except, perhaps, through the 2029 flyby.

“How Apophis itself responds, that’s physically about how Apophis is put together. And that’s something we don’t know — we don’t know how asteroids are put together, we’ve never been able to peer inside an asteroid,” Binzel said. “We see the asteroid outside looking in. This is a chance where we could have the asteroid inside looking out. In other words, is the inside of the asteroid revealing itself by some measurement we can make on the outside?”

It’s an incredible experiment arranged purely by the coincidences of orbits.

Related: Comet Shoemaker-Levy 9’s epic crash with Jupiter in pictures

Scientists have been here once before. In 1993, astronomers spotted a new comet, dubbed Shoemaker-Levy 9 — only to realize the discovery was in fact a clutch of comet fragments, the debris of a comet that passed too close to massive Jupiter to survive the experience. But the real highlight? Those fragments were on course to slam into the planet the next year.

“The predictions for the impact of Shoemaker-Levy 9 ranged from nothing will happen — it’ll be a dud, a flop — to pretty much parallel to what we actually observed,” Binzel said. “There was enormous uncertainty as to what the outcome of the Shoemaker-Levy 9 impact was going to be simply because it challenged the state of our knowledge. And so the parallel with Apophis is that there is a wide range of predictions for what will happen physically to Apophis itself during the encounter: Apophis might go by the Earth and not care, or Apophis might go by the Earth and be tugged on so significantly that it seismically shakes.”

But in the 1990s, astronomers rallied spacecraft and telescopes alike to gawk at a week of collisions that scarred Jupiter’s clouds for a few weeks. All told, the Shoemaker-Levy 9 observations taught scientists about not just those comet fragments and the icy lump they once made up, but also about Jupiter and its atmosphere.

“I think Apophis is a lot like Comet Shoemaker-Levy 9: It’s an extremely rare natural experiment that we discovered with a short lead time,” Binzel said. “This is something that rarely happens. Nature is doing something amazing for us as a natural experiment, and the challenge is how do we take advantage of that natural experiment.”

And Apophis observations would tell scientists about a different flavor of close encounter than Shoemaker-Levy 9, since Earth’s gravity won’t be strong enough to tear the rock apart.

“It won’t cause this kind of big event but it is still meaningful to understand how the object can be affected by this a-little-bit-distant close flyby,” Yaeji Kim, a doctoral student in aerospace engineering at the University of Auburn in Alabama, told Space.com. “There is no object which has been observed in this kind of phenomenon. From that kind of view, Apophis is a really rare case.”

Related: Radar views show big asteroid 1998 OR2 tumbling in space ahead of Earth flyby (video)

Preparing for 2029

Making the most of the 2029 flyby will rely on baseline data: what scientists know about Apophis before its dramatic encounter with Earth. That means the observations gathered this year matter. Apophis will be at its closest to Earth this year on March 5 at 8:15 p.m. EST (0115 GMT on March 6).

“Closest” here is a relative term: the asteroid will remain a healthy 0.11 astronomical units (the average distance between the Earth and the sun, or about 93 million miles or 150 million km). That’s nearly 44 times the distance between Earth and the moon.

But that’s close enough for scientists’ most powerful tool for studying asteroids from Earth: planetary radar. Take a powerful radar beam, point it at a mysterious object, then wait. Use a sensitive radio telescope to catch the echo that bounces back, run it through some complicated processing, and the result is a sonogram-like image.

“We like asteroids that come close but, you know, just enough so that we can get a really good signal and we can get really great images,” Brozović said.

Related: Scientists just watched a newfound asteroid zoom by Earth. Then they saw its moon.

With good radar images, scientists can tell, for example what shape an asteroid is: potato, peanut, or even a pair of cherries bound only by gravity. Under particularly friendly circumstances, radar can detect boulders on the surface of a space rock. It also hones scientists’ ability to track an asteroid’s orbit.

Scientists’ top priority while preparing for the 2029 Apophis flyby is sharpening their view of the rock’s shape and its intricate rotations, Binzel said. “We know Apophis is in a very complicated spin state, it’s sort of spinning and tumbling at the same time,” he said. “The 2021 encounter gives us an epoch in time.”

When scientists look to make predictions about what precisely will happen to Apophis during the 2029 encounter, they’ll feed the current best wisdom of the object’s shape and twisted rotation into models — but the resulting predictions will only be as robust as the data.

Related: Losing Arecibo’s giant dish leaves humans more vulnerable to space rocks, scientists say

Inconveniently, Earth lost its most powerful planetary radar system in December, when Arecibo Observatory’s radio telescope in Puerto Rico collapsed. Each radar system has its strengths and weaknesses, and Arecibo would have shone during this preparatory close approach. Without it, scientists aren’t sure how much they’ll be able to improve existing radar observations of Apophis.

But they’ll try, thanks to the planetary radar system at NASA’s Goldstone Deep Space Communications Complex in California, which is due to study Apophis from March 3 to March 14 to cover this flyby. Researchers also hope to use the Green Bank Telescope in West Virginia to catch the echos, rather than having to switch Goldstone’s settings back and forth between send and receive; if they can use two telescopes, the data will be sharper.

“Arecibo was really a powerhouse, the most powerful radar on the planet, so we just can’t make that up,” Brozović said. “But we’re still going to get good data.”

Email Meghan Bartels at mbartels@space.com or follow her on Twitter @meghanbartels. Follow us on Twitter @Spacedotcom and on Facebook.

Live Science
By Meghan Bartels – Space.com Senior Writer

4563: “Asteróide do caos”. Novos dados confirmam que Apophis pode impactar com a Terra em 2068


(dr) Detlev van Ravenswaay

Um astrónomo do Instituto de Astronomia da Universidade do Havai revelou novas descobertas críticas relacionadas com um grande asteróide que deverá passar muito perto da Terra.

Dave Tholen e os seus colaboradores anunciaram a detecção da aceleração Yarkovsky no Apophis, o “asteróide do caos”. Esta aceleração surge de uma força extremamente fraca num objecto devido à radiação térmica não uniforme.

Esta força é particularmente importante para o asteróide Apophis, uma vez que afeta a  probabilidade de um impacto na Terra em 2068.

Todos os asteróides precisam de irradiar novamente como calor a energia que absorvem da luz solar para manter o equilíbrio térmico, um processo que altera ligeiramente a órbita do asteróide.

Antes da detecção da aceleração Yarkovsky no Apophis, os astrónomos concluíram que um impacto potencial com a Terra em 2068 era impossível. Porém, segundo um comunicado da Universidade do Havai, a detecção desse efeito a actuar no Apophis significa que o cenário de impacto de 2068 ainda é uma possibilidade.

O asteróide Apophis é digno de nota por causa da sua abordagem extremamente próxima da Terra na sexta-feira, 13 de Abril de 2029, quando o asteróide de 300 metros se tornará visível a olho nu enquanto passa dentro do cinturão de satélites de comunicação que orbitam a Terra.

“Já sabemos há algum tempo que um impacto com a Terra não é possível durante a aproximação de 2029”, disse Tholen, que rastreou com precisão o movimento do Apophis no céu desde que a sua equipa o descobriu em 2004.

“As novas observações que obtivemos com o telescópio Subaru no início deste ano foram suficientemente bons para revelar a aceleração Yarkovsky de Apophis e mostram que o asteróide está a afastar-se de uma órbita puramente gravitacional em cerca de 170 metros por ano, o que é suficiente para manter o cenário de impacto de 2068 em jogo.”

Já há preparativos para a aproximação do asteróide Apophis em 2029

Os cientistas já revelaram algumas das observações que vão levar a cabo durante a aproximação do asteróide Apophis à Terra,…

Ler mais

Outras observações para refinar a amplitude do efeito Yarkovksy e como afecta a órbita de Apophis estão em andamento. Os astrónomos saberão antes de 2068 se há alguma probabilidade de impacto.

Os cálculos da órbita foram realizados por Davide Farnocchia, do Jet Propulsion Laboratory, que é co-autor do artigo apresentado no encontro virtual de 2020 da Divisão de Ciências Planetárias da Sociedade Astronómica Americana.

ZAP //

29 Outubro, 2020


3673: Já há preparativos para a aproximação do asteróide Apophis em 2029


Os cientistas já revelaram algumas das observações que vão levar a cabo durante a aproximação do asteróide Apophis à Terra, que atingirá a sua distância mais próxima do nosso planeta em meados de Abril de 2029.

A 13 de Abril de 2029 uma mancha perfurará o céu, tornando-se mais brilhante e mais rápida. Será o asteróide 99942 Apophis, vulgarmente conhecimento como Deus do Caos, a aproximar-se da Terra, conta a agência espanhola Europa Press.

Este corpo rochoso de enormes dimensões (340 metros de largura) passará muito “perto” da Terra, ficando no ponto máximo da sua aproximação a 31.000 quilómetros do nosso planeta – estará mais perto do que qualquer nave espacial já esteve.

Apesar de este corpo passar a uma distância considerada curta a nível astronómico, a probabilidade de o Apophis impactar com a Terra é quase nula (menos de 1 em 100.000).

Na habitual Conferência de Defesa Planetária de 2019, que decorreu em Maryland, nos Estados Unidos, vários cientistas discutiram planos de observação para este evento celestial que está ainda a uma década de distância.

“A aproximação de Apophis em 2019 será uma incrível oportunidade para a Ciência”, disse Marina Brozovic, cientista do Laboratório de Propulsão a Jacto da NASA. “Observaremos este asteróide com telescópios ópticos e de radar. Com observações de radar, poderemos conseguir ver com detalhe a sua superfície a alguns metros de distância”.

O asteróide, que se verá sob a forma de um ponto de luz em movimento, começará a ser visível a olho nu no céu nocturno sobre o hemisfério sul, sobrevoando a Terra da costa leste até à costa oeste da Austrália. Depois, atravessará o Oceano Índico e, mais tarde, cruzará o equador, movendo-se ainda para oeste, sobre África.

No seu ponto mais próximo da Terra, por volta das 12 horas em Lisboa, Apophis estará sobre o Oceano Atlântico, atravessando-o em apenas uma hora.

Boa “janela” para a Ciência

Desde que foi descoberto, em Junho de 2004, vários telescópios têm acompanhado este asteróide enquanto este continua a sua órbita em torno do Sol.

Os cientistas conhecem bem a sua trajectória futura deste corpo, mas o ano de 2029 será o ano das grandes observações. Com a aproximação deste corpo, os cientistas esperam descobrir mais sobre a sua forma, composição e até sobre o seu interior.

“Já sabemos que um encontro próximo com a Terra mudará a órbita de Apophis, mas os nossos modelos mostram também que o foco próximo pode mudar a forma como este asteróide gira, e pode haver algumas mudanças na superfície, como pequenas avalanches”. disse Davide Farnocchia, astrónomo do Centro de Estudos de Objectos Próximo à Terra (CNEOS) do Laboratório de Propulsão a Jato da NASA.

“O Apophis é um representante de aproximadamente 2.000 asteróides potencialmente perigosos actualmente conhecidos”, completou Paul Chodas, director do CNEOS.

“Ao observar Apophis durante seu sobrevoo em 2029, obteremos informações científicas importantes que poderão um dia ser usadas para a defesa planetária”.

Apesar de ser muito pouco provável que um asteróide venha a colidir com a Terra nos próximos anos – a probabilidade é de 1 em 300.000, segundo a NASA -, as agências espaciais têm reunido esforços para melhorar os programas destinados para o acompanhamento e desvio destes corpos em rota de colisão com a Terra.

Nem Asteróide do Apocalipse, nem Deus do Caos. Nenhum asteróide (conhecido) vai colidir com a Terra nos próximos 100 anos

A NASA continua a afirmar que nenhum asteróide conhecido representa um risco significativo de impacto com a Terra nos próximos…

ZAP //

12 Maio, 2020



1508: Apophis, o asteróide do caos, poderá colidir com a Terra em 2068

(CC0) RafaelMousob / Pixabay

Em 2004, os astrónomos descobriram o Apophis 99942. Em 2068, este asteróide poderá vir a colidir com o nosso planeta.

O asteróide Apophis 99942, descoberto em 2004, poderá atingir a Terra em 2068. Mas, antes disso, este corpo celeste deverá aproximar-se do nosso planeta em 2029, a uma distância dez vezes menor do que a existente entre a Terra e a Lua. A informação é avançada por cientistas da Universidade Estatal de São Petersburgo, na Rússia.

Baptizado em homenagem ao antigo Deus egípcio do mal, da escuridão e da destruição, Apophis 99942 deverá ficar a apenas 37.800 quilómetros da Terra, ou seja, cerca de um décimo da distância entre o nosso planeta e a Lua – que é de 384 mil quilómetros.

Os cientistas alertaram que esta rocha espacial, que tem um diâmetro de 325 metros, poderá atingir o nosso planeta em 2068 a uma velocidade de 7,43 quilómetros por segundo.

“A aproximação do Apophis 99942 com a Terra causa um aumento significativo de trajectórias possíveis, entre elas as que preveem uma aproximação maior em 2051”, informam os astrónomos no relatório citado pela SputnikNews. Os dados científicos referentes ao asteróide revelam ainda cerca de 100 “possíveis colisões do Apophis com a Terra, sendo a mais perigosa em 2068“, adianta o documento recém divulgado.

Antes da aproximação em 2068, o asteróide aproximar-se-á da Terra em 2044 a uma distância de 16 milhões de quilómetros e, em 2051 e 2060, a uma distância de 760 mil quilómetros e de cinco milhões de quilómetros, respectivamente.

Cientistas da NASA já tinham alertado para a possível colisão entre o Apophis e a Terra, mas adiantaram que a probabilidade de colisão seria extremamente pequena.

Os cientistas estimaram também que havia uma probabilidade de 2,7% de este corpo celeste vir a atingir a Terra em 2029. No entanto, os analistas excluíram esta ameaça, estimando que, a 13 de Abril de 2029, o Apophis irá aproximar-se do nosso planeta a uma distância de 37.800 quilómetros do centro da Terra.

Segundo a RT, as descobertas da equipa russa serão apresentadas no Korolev Readings on Cosmonautics, um evento que se realizará em Moscovo no final deste mês.

Os cientistas admitem que não conseguem calcular com precisão o comportamento do asteróide devido à sua órbita irregular que mudará de forma no futuro.

Boris Shushtov, director do Instituto de Astronomia da Academia Russa de Ciências, assegura que Apophis 99942 não está entre os corpos mais ameaçadores para o Sistema Solar e acrescenta que sua probabilidade de colisão com nosso planeta é muito baixa.

ZAP // SputnikNews

22 Janeiro, 2019