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<p><strong>Apophis</strong> (nome astronômico <b>99942 Apophis</b>, previamente catalogado como <b>2004 MN<sub>4</sub></b> ) é um <a title="Asteroide" href="http://pt.wikipedia.org/wiki/Asteroide">asteroide</a> que causou um breve período de preocupação em dezembro de 2004 porque as observações iniciais indicavam uma probabilidade pequena (até 2,7%) de que ele iria atingir a <a title="Terra" href="http://pt.wikipedia.org/wiki/Terra">Terra</a> em 2029.</p>
<p>Após o anúncio do possível impacto pelo Sentry e NEODyS, observações adicionais diminuíram a incerteza sobre a trajetória do Apophis. E, conforme diminuía a incerteza, a probabilidade de um impacto temporariamente cresceu, chegando ao pico de 2,7% (1 chance em 37). Combinado com seu tamanho, isto fez com que o asteroide fosse classificado no nível 4 da <a title="Escala de Turim" href="http://pt.wikipedia.org/wiki/Escala_de_Turim">Escala de Turim</a> e 1,10 na <a class="new" title="Escala Técncia de Risco de Impacto Palermo (página não existe)" href="http://pt.wikipedia.org/w/index.php?title=Escala_T%C3%A9cncia_de_Risco_de_Impacto_Palermo&action=edit&redlink=1">escala Palermo</a>, escalas usadas pelos cientistas para representar o perigo de um asteroide atingir a Terra. Estes são os valores mais altos que qualquer objeto já recebeu nas duas escalas.</p>
<p><font color="#ff0000">Na sexta-feira, 13 de abril de 2029, o Apophis irá passar pela Terra entre as órbitas de </font><a title="Satélite de comunicação" href="http://pt.wikipedia.org/wiki/Sat%C3%A9lite_de_comunica%C3%A7%C3%A3o"><font color="#ff0000">satélite de comunicação</font></a><font color="#ff0000"> </font><a title="Órbita geossíncrona" href="http://pt.wikipedia.org/wiki/%C3%93rbita_geoss%C3%ADncrona"><font color="#ff0000">geosíncronos</font></a><font color="#ff0000">.</font><sup id="cite_ref-4" class="reference"><a href="http://pt.wikipedia.org/wiki/Apophis#cite_note-4"><font color="#ff0000">[</font>5]</a></sup> Depois desta passagem ele irá retornar para outra passagem próxima à Terra em 2036.</p>
<p>Observações de "<a title="Precovery" href="http://pt.wikipedia.org/wiki/Precovery">precovery</a>" de 15 de março de 2004 foram identificadas em 27 de dezembro, e um cálculo mais preciso da órbita foi feito.<sup id="cite_ref-5" class="reference"><a href="http://pt.wikipedia.org/wiki/Apophis#cite_note-5">[6]</a></sup> Astrometria feita com <a title="Astronomia de radar" href="http://pt.wikipedia.org/wiki/Astronomia_de_radar">radar</a> ajudou a refinar a órbita. </p>
<p>A passagem de 2029 será mais próxima que as primeiras predições, mas a incerteza baixou a ponto de permitir descartar a possibilidade de impacto. De forma semelhante, a passagem de 13 de abril de 2036 tem pouco risco de impacto.</p>
Fonte: Wikipedia</div>
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<div>Russian beacon to track menacing asteroid Apophis</div>
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<div><img alt="AFP Photo / NASA " src="http://rt.com/files/news/apophis-radio-beacon-mission-908/afp-nasa-photo.n.jpg" width="370" height="277"> </div></div>
<p>AFP Photo / NASA </p></div>
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<p>Russia’s space agency wants to send a mission to Apophis, the notorious asteroid which may change its course and eventually collide with Earth. It will plant a radio beacon, which will help track the celestial body and assess the risks it poses.</p>
<p>The 300-meter-wide asteroid first made headlines in 2004, when NASA reported that it has 1 chance in 223 of impacting on our planet in 2029. It was even named after the Ancient Egyptian evil god, archenemy of the sun god Ra.</p>
<p>But additional observations proved that it will pass by at the small, but safe, distance of some 36,000 kilometers from Earth. The close approach however may result in an unpredictable gravitational pull on Apophis, which would change its course and pose a danger in 2036, when it comes back.</p>
<p>To better assess the risks it poses to the civilization the Roscosmos plans a robotic mission to the asteroid, chief Vladimir Popovkin announced on Monday.</p>
<p>The plan is <em>“to land a module on the surface of Apophis and set up a radio beacon there, which will work after the spaceship’s lifetime expires,”</em> he said at the Space Research Institute in Moscow.</p>
<p>The beacon signal will allow astronomers to better calculate Apophis’ movement and the effect of the 2029 Earth flyby. The mission would not be launched before 2020.</p>
<p>Popovkin, who was speaking at a solar system exploration conference, outlined other mid-term plans Roscosmos has. These include a Venus orbiter between 2020 and 2025, which will study the planet’s hot and dense atmosphere. The mission may include a descending probe, although due to the harsh environment it would only work for about one day on the surface.</p>
<p>Another target is Jupiter’s moon Ganymede. Roscosmos plans to send a spacecraft there in 2022 and is currently negotiating with its European counterpart ESA, which has a similar project, over a possible closer collaboration.</p>
<p>Russia also plans a new Mars mission. Popovkin said launching such a spacecraft is no less important after the embarrassing failure of Fobos-Grunt in November 2011. Now engineers will be able to learn from the mistakes of the original attempt to reach the Martian moon.</p>
<p>A more immediate plan is the Luna Glob mission to the Moon scheduled for late 2015. It would include returning a soil sample to Earth and studying it from an orbiter, which would change its altitude from the initial 100 kilometers down to 50 kilometers and later to 500 kilometers. The soil would later be studied for possible extraction of water from it.<br>
<em><br>“We will allocate our main effort and majority of resources to the moon,”</em> Popovkin said.</p>
<p>Fonte: RT - "TV-Novosti"<br></p></div>